This is probably the best explanation of this phenomenon that I've seen. I'm going to refer to this in a future video for sure. One of the most frustrating "objections" when it comes to alternatives to driving is that many people need to drive, and (today at least) there may be few people who can take advantage of these alternatives in a car-dependent city. It's annoying that this "objection" ignores future travel demand, but it's even more frustrating because you actually only need to take a small number of cars off of the road to make a hugely positive difference to congestion. You didn't quite say it in this language in this video, but you hinted at it: the difference between free-flowing traffic and stop-and-go traffic can literally be just a few cars. Which means that even if, say, a dozen rush hour drivers cycle instead, it can have a massive contribution to better traffic flow. I recently made a video about how driving is awesome in the Netherlands, but I have a feeling that most suburbanites are never going to understand this. Edit: by the way I searched for lazer dix on my channel and he's a car enthusiast who was triggered by my noise video. Some of these people do not appreciate being reminded of what the damage their "hobby" causes to society, and when somebody does, they try to paint them as irrational car-haters. There will always be selfish people who want to stand in the way of progress, but that's why we need to keep fighting for better cities.
There's really three dimensions to changing car-brain: buildings, streets, and vehicles. We need to show them how all three work together to make a new living space. Zoning, street design, and new vehicles they may not have heard of like e-bikes, cargo bikes, trams, light rail, and others are part of a great urban landscape.
@@lazerdx Wow. Keep your shirt on pal. Maybe 'Not Just Bikes' is not professional enough for you but he's often humorous and gets his point across in a non-conflicting manner. Which is more than can be said for those who fly off the handle (bars). 😆
@@pappy9473 The quality of his content is not what I was complaining about in the slightest, and for the record his passive aggressiveness in comments makes me look like Mother Theresa (the idealized version, not the real one).
This is your best one yet, by far. I'm sure these kinds of videos take significantly more effort than the top 10 lists, but this is the one that made me subscribe. Keep it up!
@@CityNerd I would love to see a video on how commute time affects lower income families as they get pushed out of the city centers. It's a serious problem in cities like SF
I used to take an exit in Mountain View (101 N to Shoreline N) that would back up at the light from 8 am to 11 am, and let through ~30 cars a cycle. I once (while siting in the traffic) figured out that every car that decided to use the exit caused a car after them to miss a light at EVERY traffic cycle, which was about 2 minutes long. If a car showed up at 8:02, the next 90 cycles would each have one car shifted to the next cycle, and therefore be delayed by 2 minutes. That works out to 180 minutes of delay PER CAR!!! Congestion is non-intuitive... I usually showed up around 10:30, so I was only delaying a few cycles after me, but this realization strongly encouraged me to take my bike.
When I was a kid in the 90s my central Mexico hometown started building more road infrastructure like overpasses and interchanges, when the city was about 500K inhabitants. My relatives joked that all those new bridges were excessive for our "small" city. Now, 25 years later, the city is over 1M inhabitants, lots and lots of viaducts and underpasses have been built, most of them on the access roads to the city and the ring roads, however when a new underpass is under construction it always gets messy. Public transport was and still is lackluster, so even working class people bought cars to move around. It has just gotten worse. I recall my childhood years of empty roads, they're gone. I don't know if the civil engineers are in bed with the local government or the fact we have the largest Nissan plant on Latin America has fed the car culture.
I happened to go visit Aguascalientes twice in 2007 -8. I liked the idea of the city rings, but even then, traffic congestion was almost the same as here in Mexico City. I blamed then the climate, since there was in the raining season and wrre a couple of stoms that made a real mess in downtown... Three blocks walking along a flooded road to cross it to walk back to downtown Steren...
That's the story pretty much everywhere: build roads and there will be cars and traffic and chaos. Build active/public transport, and people will move quietly and efficiently.
That first possible solution is more or less the one everyone think will work: "1 more lane will do the trick!" It just makes the cities even worse for pedestrians with massive stroads and these intersections so large that even with pedestrian traffic on crossing it is basically suicide.
And the adding one more lane also runs into the issue of induced demand. The easier it is to make a particular journey, the more people make that journey. So you add one more lane, then find that a couple of years later the congestion is just as bad as it was before because the extra lane means that more people are driving on that particular stroad.
This is also kind of why airport security lines (for example) appear either empty or backed up significantly. When the system is at or just below capacity, all is empty. When it's just 20-30% over capacity, it's 100% lined up.
It has been my experience that cities which have successfully eliminated or seriously reduced traffic congestion have used none of the solutions mentioned in the video. Instead they have implemented measures that make walking, cycling or public transit the fastest, easiest and most convenient way of safely going from A to B. I will give three examples. The first is Groningen in The Netherlands. This uses a neighbourhood zone strategy. This means that people walking, cycling and using public transit can go straight from A to B. But concrete and steel barriers prevent private automobile drivers from going directly from one zone to an adjacent zone. For private automobile drivers to go from one zone to the next, they must drive out of the zone to the surrounding ring road. Then drive around the ring road to the outer edge of the zone in which their destination lies. Then drive in through the zone to their destination. This has the effect of making walking, cycling or public transit the fastest, easiest and most convenient way of going safely from A to B for a very large percentage of trips in Groningen. The second example is Ghent, Belgium. The introduction of its Traffic Circulation Plan put affected streets into three categories. Category 1 Car-free. Category 2: Motor vehicles are restricted to local residents, local merchants and their suppliers, public transit vehicles, taxis and emergency vehicles. Category 3: A neighbourhood zone strategy, similar to the above one for Groningen. Ghent's Traffic Circulation Plan resulted in rmaking walking, cycling or public transit the fastest, easiest and most convenient way of going safely from A to B for a very large percentage of trips in Ghent. The third example is the city of Utrecht in The Netherlands. It has an extensive car-free downtown. The motorway that was built upon the city moat was removed and the moat restored. And on other streets, there has been a steady shift in use that took away space that was previously used by motor vehicles in order to create fantastic cycling infrastructure. Once again, the effect has been to make walking, cycling or public transit the fastest, easiest and most convenient way of going safely from A to B for a very large percentage of trips in Groningen. I strongly disagree with the statement: "Every city has problems with growing traffic congestion." These three cities do not, and neither do many other cities around the world. The one thing that they tend to have in common are measures that make walking, cycling or public transit the fastest, easiest and most convenient way of safely going from A to B. I highly recommend Mark Wagonbuur's blog, "Dutch Cycling." It provides an excellent description of Utrecht and many other places in The Netherlands.
True! You can't just make driving less accessible with congestion pricing without delivering better infrastructure for the alternatives. Also, cars are just an extremely space-inefficient mode of transportation that's not suitable for cities because of the limited space available. Every city where the main mode of transportation is cars will have congestion issues. The solution is using more space efficient modes of transportation.
@@lb2791 Very true. In cities where the main mode of transportation is the bicycle, it would be impossible to start using automobiles for transportation. The laws of geometry dictate that there just is not enough space to put that many large metal boxes on the street. It is annoying that RUclips no longer allows me to post links. Mark Wagonbuur has produced an excellent video of Vredenburg in Utrecht for his "Bicycle Dutch" blog. This street is used by 32,000 people on bicycles each day. It would be impossible for them to start using automobiles. Just not enough street space. Or space for automobile parking. One of the most fascinating parts of the video is the "before and after" shots. Before the street went car-free, it was a nightmare of congestion. Now traffic flows freely. Please search with RUclips's search function on "Bicycle Vredenburg."
I’d be interested in a video on Carmel, IN which is a suburb of Indianapolis that is known for its roundabout obsession. Ironically, it is home to the nation’s first stoplight.
Carmel, IN is super interesting. Check out Bend, OR too! Roundabout analysis is a lot different, but it tends to break down later for a lot of movements. Tradeoffs with amount of land consumed and bike/ped integration, too, of course.
Roundabouts are interesting when considering their failure modes. Roundabout evangelists often insist that roundabouts are the solution to everything, but there are cases where they fail hard, particularly in asymmetric traffic volume scenarios. If a roundabout has signals, it has probably reached failure point, at least during some portion of the day. An analysis of the situation would certainly be interesting. Also compared with an all way stop, which seem to be everywhere in my neck of the world. (No, all way stops are not the solution to everything, either. They're used around here in many cases where a roundabout would be better.)
Would love to see a video detailing “smart” traffic lights in the US. The one for my street seems incredibly dumb, like it is only programmed to ever save time on the busier cross street rather than consider the actual traffic conditions at the time.
@Zaydan Naufal is it that much more expensive? If traffic flows better there is less stress from it, people will be less tempted to drive through a red light, and people have more time to spend wherever they are going. If the costs of a smart traffic light are higher than the returns from it I would wonder if a traffic light is the smartest thing to have in that place.
Yeah, my theoretical traffic signal here is slightly dumb -- you would hope that there would be an algorithm behind it that occasionally allocates additional time (recovery time) to over-capacity movements.
This is a great explanation, but as a math/cs professor, I have a quibble: this shouldn't be described as exponential growth. The effect is clearly super-linear, but would be better described as quadratic (x^2) than exponential (2^x). The effect here is quadratic because each additional car ADDS time that grows with the number of cars; exponential growth would mean that each additional car MULTIPLIES the time by a constant factor, which would have a much, much bigger cumulative effect. In this context, either quadratic or exponential would be bad, but in other contexts (like disease spread) there's an enormous difference between these growth rates!
I would love to hear more about congestion pricing! I live in San Diego, and our grand transportation plan just lost its mileage tax provision because the city council cut it due to public opinion/messaging. Now the city's big goals on many things--including multi-modal transportation upgrades--are possibly not paid for in the long run... developing story!
I'm no expert but it seems like tolls and the like mostly serve the wealthy. Any additional pricing on drivers is going to push more people into poverty, which is already at crisis levels. Maybe use it to help push middle class folks to bike & rail networks once you've made those viable choices, but at that point it's probably not necessary.
@@NickCombs Exactly. These kinds of schemes are regressive and hurt the poor the most. The well off don't care about having to pay more to drive to work (or more for gas in the form of a "carbon tax") but it can be a severe burden on those on the margins who just want to go to work.
@@CityNerd Here in New York City, the CP plan hasn't yet been developed, but I suspect that nobody trusts that whatever money is raised via the fee will go to where it is supposed to go and also that whatever money does get to its destination, it will be spent inefficiently. I await your video on CP. BTW, you've gotten another sub as a result of this video.
@@NickCombs That is why you have to make sure that there are good and reliable alternatives (mass transit for instance) before you do this, which is why this can't be a measure on its own, but has to be part of a larger plan. And also the price doesn't have be massive. See what Stockholm did for instance. I don't know the exact numbers, but the price was not high and it had a massive effect.
Traffic congestion, like other issues related to city/community life, requires a unified, system based approach. Number of car trips is related to number of dwellings and to work/school/shopping locations and is closely linked with income. (not everyone can afford to own a car) Part of our challenge is that all these factors are viewed/managed by separate agencies/interest groups. Lack of unity is an overall limiting factor as regards mitigation of problems or improvement of the quality of life.
The number of car trips is also related to where people live in a city. For example, those who live in the downtown car-free zone are unlikely to own a car.
@@kevinlove4356 Wish this were true. Desire for route, Increases directly compared to number of people involved. Regardless of where, these numbers follow similar patterns. -- Have you ever tried to park, downtown ? Obtain twor forms of grid-lock ! -- Numbers of vehicles, -- Numbers of people wishing to use the mass transit system.
Interested to see if this compounding effect is apparent for freeway lane closures, and the effect that more lanes of traffic get better or worse with the same number of lanes closed
Interestingly the opposite was observed during the viadoom “carmageddon” in Seattle when the closed the viaduct but wouldn’t open the tunnel for another 3 weeks. The city added a bunch of transit options, including more water taxis, encourage people to work from home etc. and it worked. Traffic did not increase significantly during the closure. Ironically the missing carmageddon following the viadoom was used to demonstrate that Seattle doesn’t really need a waterfront highway. You can literally close a major highway and enact policies which eliminates the traffic. Sadly policy makers have yet to learn from this in Seattle. The tunnel is now open and they are in the process of building a major arterial road above it (see also West Seattle bridge fiasco).
It does. It's also the reason some freeways use signalized entrances to slow the introduction of cars to the freeway. By stopping just a few cars you can make the congestion go away.
Analysis of "interrupted flow" (signals, stop signs) facilities and "uninterrupted flow" (freeways) facilities is completely different -- different enough that they warrant totally separate volumes of the Highway Capacity Manual! I may do another version of this video in the future looking at freeways instead.
@@CityNerd Here is a video idea: “Top 10 carmageddons that never were”, a list of high profile highway closures which predicted a bunch of extra traffic, bu only a fraction of-if any-increased congestion was realized.
As a delivery driver: I can assure same teaffic congestion for any temporary route changes. Avoiding the peak congestion times, Quickly reduces delivery times. Because of this: I refuse to do deliveries during peak times. ( 2 hours in a.m. AND 2 hours in p.m. )
Since I only derive utility from sitting in traffic, this is the best news I have ever gotten. I will watch the rest of your videos while driving around my F150. *I* am the congestion.
Been driving for 40+ years, professionally for 13+ of those years, and I would argue that 60%-80% of traffic problems (particularly on freeways) are due to a small percentage of 'oddballs' - people who don't (usually won't) conform to surrounding traffic. While they're halfway tolerable when congestion is minimal, a single oddball can potentially shut down an entire freeway if traffic is at least half of the design capacity. The first mantra of professional drivers is "go with the flow". It's almost hilarious when some looney flies past me going ±15 MPH faster than the rest of traffic, weaving between lanes (usually without a single turn signal), only for me to pull up alongside them at the next traffic light. The same happens in the opposite direction when someone insists on driving slower than the rest of traffic, particularly when they do so anywhere other than the rightmost lane. Even then, it doesn't take long before other drivers become more prone to take undue risks in order to switch lanes and get around the oddball. When traffic is light, the impact of either extreme is negligible - there are plenty of opportunities to change lanes at minimal risk. But as soon as congestion begins to build, changing lanes (especially if going a different speed than prevailing traffic) becomes exponentially more dangerous. Furthermore, drivers who are overtaken at speed have a tendency to panic and reflexively hit their brakes; seeing brake lights ahead, the next driver hits their brakes (likely harder than the person ahead of them had), etc. You very quickly have people slamming to a complete stop in the middle of the freeway for no reason whatsoever. Which means that someone is likely to switch lanes suddenly, bringing adjacent lanes to a screeching halt as well, expanding to include the entire roadway - sometime even ensnaring oncoming traffic in the process. And all because ONE driver insisted on going 10 MPH slower than everyone else on the freeway.
As someone who lives in Fort Myers and has taken the intersection shown in the video hundreds of times, the solution shown does not work even though it looks nice. That intersection does not get congested often, but the left turn wait times are heinous for all turn lanes. Usually 3 minutes or more between cycles and so when it does get congested during our tourist season people are left waiting 7 or 10 minutes to turn left onto 41. And therefore it’s my most despised intersection in the city. Funny to see it on here, your best video yet!
I actually included it because I stayed at a hotel like a block away from there and that intersection (and land use context) just blew my mind. The cycle lengths are atrocious. Exhibit 1A when you value volume/capacity ratio as your performance metric over everything else. I still had a good time in Fort Myers, though! Baseball and beach time in Feb/Mar can't be beat.
Could you do a video talking about how citizens can help influence public policy in their own cities around issues such as this? Congestion pricing sounds like a great idea, but given how the recent attempt to implement a parking management systems (paid parking) in my own city was received by the population, it sounds like it would be a really hard sell. Not saying specifically to do a video talking about how to get congestion pricing implemented in a city, but how to advocate for positive change in regard to urban transportation. Maybe a top 10 examples of times urbanist advocacy groups made stuff happen in cities in North America and how they did it?
Conventional advocacy is not my wheelhouse (my background is consulting), but I have massive respect for the people who are good at advocacy and navigating the political system -- and I know a few of them. Let me give this some thought.
Raising costs is only going to punish the poor, and create a road class system, like we have a housing class system. We already have enough toll roads. There are many other things to try first. Sure public transport is a good option for some people, but how about incentives for people to ride a motorbike or scooter?
@@tubester4567 my city tried to incorporate congestion pricing too but it immediately got labeled as a money grab by the government and it hasn't gone through. I would agree that it will def hurt the poor more. Subsidizing their cost based on their income might help but then things get complicated and you have more paperwork and forms to keep track of as a citizen. My other question is how else can we fund public transportation or other modes of trransportation? Any move on trying to collect money for the betterment of the whole community leaves people angry. Americans hate getting taxed. So what's the solution?
@@shreyas9701 I am not an American nor living in America. After watching all these videos, my understanding is, you guys shall fix the city planning and zoning first. Before single family houses reduce to a certain percentage (which may never happen as it is a cultural issue), the immediate traffic fix is NOT congestion pricing. The band-aid is encouraging e-bikes and e-scooters for rush hour job home travel. They are fast enough to ride on the motorway and they are far smaller in size so the same road can pack a lot more of them. Then the next step may be to build railway lines that allow people to ride / bring their bikes / e-bikes / e-scooters onto the train and travel with them. Now the bikes and humans are more closely packed and move even more efficiently.
This is one of the factors, but a really significant one. Other factors contributing to exponential growth of traffic also include these: - Land use: as cities sprawl more and more, the average trip length grows. Each trip then contributes to congestion along more portions of the road network. Suppose you have an arterial with signalized intersections every kilometer. Someone living in the inner suburbs 5km away would likely affect up to 5 intersections; but someone living in outer suburbs 10km away would affect up to 10 intersections, if they're heading to the same city center. All of the congestion-causing phenomena effects mentioned in this video manifest at more places, generating gridlock. - Induced traffic demand: believe it or not, people have a surprisingly high tolerance and flexibility for congestion. If a major route has its capacity increased through geometrics (ex. more through lanes, more turning lanes at intersections, grade separations) this reduces travel time in the short-term. The effect of this is people who were using strategies to avoid congestion (alternate routes, alternate trip times, carpooling, alternate destinations, trip avoidance transit as a back-up option when they'd rather drive) will pour into the main route, and them vacating the alternate route attracts more trips elsewhere. In the long-term, the expanded capacity makes long-distance trips more attractive, encouraging sprawl. - Traffic incidents: situations which obstruct traffic can have an outsize effect on congestion, such as car crashes, disabled vehicles on the roadside (or sometimes in the lane if there's not enough shoulder/berm space available), inclement weather and so on, will create localized disruptions to the traffic network. Add up enough of these, or do just one of them on a busy route, and this will propagate congestion big time. There's also a risk of secondary traffic incidents caused by the initial incidents, which may mean the first incident's effects alone can create a prolonged disruption.
I think that's the thing that really gets me about autocentric transportation planning. The only thing that makes it viable is a roughly static number of drivers driving a roughly static distance, and socioeconomically speaking, the justification for pouring all the resources into that type of transportation development is essentially that the economy will always be growing and more people will always be driving more.
@@GeorgeMonet You're assuming that people are living so far away from their work by choice. Restrictive zoning laws--both against higher-density residential and mixed-use zones--means there's no reason to assume that's true.
Exceptional video! One thing to also keep in mind for perspective on the inefficiency of cars is that each cycle in this example there are ~7 people moving through the intersection.
This is great! I wish I could share this on my local Facebook community group and that people would actually get it... instead of constantly demanding local reps try and make their drive smoother, instead of considering alternatives.
It would be amazing to see you tackle all this issues with Cities Skylines. It would be so interesting to watch you build your own city, with public transport, traffic and motorways. You should try it!
Really enjoyed the video, getting into the math is really interesting and I think you could even cover more advanced or complicated math. The graphics were really helpful, how do you make them? I would love to see a video exploring congestion pricing along with induced demand, and the effect (or lack thereof) of transportation alternatives on congestion!
One other thing that can compound the aforementioned inefficiencies is bad weather/road conditions (especially when you're like me and driving in Canadian winters) Since cars take longer to accelerate and have to be slower in general on ice, road capacity can be temporarily reduced and cause the same exponential traffic jams. It can pretty easily turn an otherwise normal intersection into waiting 20+ minutes for a left turn...
Great video. Also, I want to add to the voices encouraging you to do more along these lines, in terms of video structure. The top 10 lists are entertaining (and possibly useful for somebody considering a move), but stuff like this is way more interesting and rewarding.
Loved the video. I personally have to say I do enjoy these kind of videos more than the top 10s (which are still very interesting) and I really would be delighted to see more theoretical videos in the future. One completely unrelated thing, I was wondering if you could maybe do a video on the public transport system in Karlsruhe (Germany). I find that an very interesting one because 1. The city isnt really big, and it's always interesting to see smaller citys develop public transport systems. 2. It is an early adopter in multy system trains with trains running on the normal tram Tracks and the Deutsche Bahn Tracks even running on the same tracks as the ICE (high speed rail) 3. They just finished a huge infrastructure projects with an downtown city Tunnel which replaces trains running through the pedestrian zone. 4. The network is huge for a city that size with trains running from the city centre to quit remote places in the mountains (Freudenstadt is 80km away) 5. The system grew extremely nicely by using existing tracks which where underused and is completely electrified 6. It kind of shows that quite good service can be given to very remote region's I don't know if you would be interested in this system, but I always found it very interesting especially as an model for city's which may be interested in improving there systems cheaply.
I just recently saw your videos. I love it, it’s way in my interests and I’ve subscribed and talk you up regularly. For me, it’s really eye opening that a very few people making different choices can massively improve things. I’ve taken to doing a fair bit of my work transportation on a commuter train with a scooter or EUC to and from the station, and lots of my local errand trips on an ebike. People really don’t recognize what removing traffic lights from your trip accomplishes. Many of my trips are faster than driving. This is in the DC suburbs. Great work!
Excellent video, I write you from one of the most congested cities in the world, Bogota Colombia. I love your math and technical take on this issue, that is the non trivial explanation we all need for the exponential nature of traffic jams. In what concerns solutions, the main ones are to pay for congestion (i.e. to make one-driver cars a very expensive privilege) and to have massive, humane, accesible transit in particular, metro lines. Greetings from Colombia and excellent content!
Great video as usual! I love it when videos reinforce what I'm learning in my classes, and this works through a lot of what we covered in doing a corridor study (things like modeling queues and the impact of implementing tolls with a transit cross-subsidy).
Wow, this was an awesome video! I really can tell you spent a lot of time on this, especially the graphics. What did you use to make those? I'd love to see more of these style. Exciting to see this channel growing!
My graphics studio is top secret! I have a crack team of underpaid keyboard jockeys sequestered at a Black Site, toiling away with limited food and water on hand. Need-to-know basis!
Couple ideas for future videos: 1) Top 10 (or bottom 10) cities in terms of the condition of infrastructure. As a San Francisco resident, I'm consistently shocked by the condition of the roads here and how the city (and state for that matter) completely shut down any time it rains. I feel like other cities handle much worse weather far better. 2) Does it take longer than it used to build big projects in the US, and if so, why? Again, as a CA resident, it seems like even simple projects, like adding a BRT Lane to Van Ness, take an incredible amount of time to complete.
Good video...but I actually think a better way to illustrate exponential congestion is with on/off ramps as opposed to traffic lights. The problem with a freeway is there is a finite space-time window to enter/exit a freeway via the far right or far left ramp. So a 10 lane freeway doesn't have 5x the capacity of a 2 lane freeway, because the cars can't use the lanes equally. Each lane change creates slowdowns for traffic behind you, and many vehicles have to stay close to the exit lane to get off...which in turn bottlenecks the cars trying to get on. On top of this roads take up a lot of space which results in lower density development and forces longer commutes. A final thought experiment to prove my point...would a 100 lane freeway still suffer traffic jams? I would argue yes, because the ramps and not the lanes are the bottlenecks most often. I actually think a 100 lane freeway would be a good video topic to prove many concepts.
@@stevengordon3271 I think that's accurate. Or, they know, but it is just so, so , so much easier to just do the same thing you did last year, or ten years ago.
@@stevengordon3271 most of us (engineers) do understand the problem. But getting clients (cities/counties) to buy in is tough. They come to us with a single congested road, and want it to handle more traffic. They'll hire another firm for the job if our proposal is to invest in bus route and bike lane expansions.
@@stevengordon3271 in an oversimplification, yes. I wanted to get across that, in general, the project isn't as vague as "improve traffic". By the time it gets to a transportation design consultant, the client has defined the project more narrowly as "come up with ways to add a lane to improve traffic throughout". The most leeway we get is in how we arrange lanes or handle parking. Coming back to the city with a recommendation to improve transit to reduce traffic demand is not addressing their actual project. Now the place where we can make these recommendations is if you get a contract for something like a city masterplan. In that, you can push for investment in transit to mitigate future traffic congestion.
Awesome video! I’ve always had trouble explaining these types of congestion scenarios to friends/colleagues but this is the clearest I’ve ever seen it explained. Will definitely be sharing this video to others instead of trying to explain this myself!
Thanks a ton! I also would love to see studies about how likely people are to be on their phones not paying attention and the like at various levels of cogestion - I feel like observing other drivers anecdotally (and myself) suggests that not only is it more likely for there to be a person doing that, but everyone prone to doing that is more likely to do so the more congested (and thus disengaged/frustrated) drivers are
So glad that I've found your channel; you have lots of interesting videos related to urban planning, especially on transportation! Can't wait to watch your past videos!
Fortunately all of my countrymen understand math, so they are all in with this. The hands down discussion of congestion is a brilliant piece of work. Best math explanation imaginable, concrete and accessible. CGPGrey like brilliance.
Not so sure about congestion pricing, but parking pricing - definetely yes. The ideal situation is where you have a car at home (if you want to own one), but the parking at your destination is expensive enough so that you don't actually use it. Now you might ask why own a car if you wont use it. My experience tells me that public transport is almost impossible in rural areas, forests, minor intercity routes, etc. And I do road trips a lot. At least one kind of lifestyle requres a car even if not using it in the city for everyday transport.
Yeah, to me "congestion pricing" is an umbrella term that includes a lot of potential strategies, cordons, tolling, VMT pricing, and definitely parking. I'll discuss more in a future vid.
I am a Practitioner of Traffic Aikido. At the root of my traffic driving is AVOID RUSH HOUR. SECOND is the MANTRA, FAST IS SLOW AND SLOW IS FAST. MEANING... don't ever exceed the posted speed limit. And...drive closer to the mean speed during Rush Hour including in the calculation the time standing at intersections and or jams and not moving. So, that means in a local road with a 45 mph posted speed limit, I will try to dive NO FASTER than 37 mph and slow down well before Red lights to attempt to avoid complete stop of my vehicle. This directly confronts the prevailing Race to the Next Red Light mentality. Not only do these cars seldom "beat" Yellow cautions indicators, they often run Red lights which is one of the most prevalent causes of car collisions.🎉 And iif they stop, wait the 120 seconds to race off again, often I roll up along side them just as they start to move. It's counterintuitive. But it works except it elevates my chance of being a victim of ROAD RAGE. You know what they say? Lead, follow, or get out of the way. Mostly I choose GET OUT OF THE WAY. I'M NOT AS STUPID AS I LOOK.
I live in London (UK) and the congestion charge definitely helped matters but I don't think it's gone far enough. Congestion is still terrible, despite having a great commuter rail system and the Tube, I still see a lot of single occupancy vehicles driving into the city every day. I think the zone needs to be enlarged and charges increased further. I say this as a driver. I drive into the city (occasionally) for work because I have to (I carry a lot of gear in my car, which I couldn't take on the train or bike), but I see many people who really don't look like they need to be in a car. If the charge was higher, a lot of those would go and things would get better for everyone else who have to use the roads.
I don't know if I'm up to date on the London cordon zone. Has it expanded or contracted recently? Any recent studies on pricing/volume? I think the pricing structure and geography need to be revisited regularly to keep it useful and equitable.
@@CityNerd There was a western extension that was removed about a year after after its introduction. I think it should probably come back. Recently there was a new Ultra Low Emission Zone (ULEZ) introduced (a toll on gas guzzling vehicles) but my anecdotal experience so far is its made no difference. Perhaps time and official data will tell the full story.
I'm curious about the impact on lower income individuals who can't pay the extra fee? My city tried to implement this but it got shut down immediately and was labeled as a cash grab by the government. I should mention I live in America and all Americans hate taxation. But without some sort of tax how can we even start funding for better public transportation or infrastructure for bicicyle lanes etc? Not to mention how car centric and difficult it is to go anywhere without a car. So it's not fair to force people to not use cars when we don't have good alternate modes of transportation but we can't get alternate modes of transportation without a tax. It's like the Catch 22. sigh...
@@shreyas9701 Yeah, the U.S. is a bit screwed in that sense. Over here, if you can't afford it, you just walk, bike or take the train. I think probably the key in the U.S. will be to densify development in certain areas, with mixed use zones and develop walking and biking (and eventually transit) around those areas, and make sure that's where the affordable housing is located.
@@mdhazeldine right- it sounds impossible to try to get any mixed use urban planning done. Everyone loves their car and single family homes too much 😭 I might just move to a different country. Nothing is gonna change in America anytime soon.
Excellent! This is a great micro analysis on how cars on the road effect one intersection. I wonder what kind of study there has been on the macro level of congestion. When each car causes exponential growth of delays, the whole system is going to be strongly effected by the average trip distance. Does 1/2 the number of cars traveling twice the distance cause the same amount of congestion? This has huge implications for suburban growth and development patterns.
Long story short: yes. Cara travelling through lots of intersections will use the capacity of these intersections. Shortening trip length world indeed reduce congedtion. Source: I am not a professional, I just play cities skylines.
Your top 10 videos are good... But I really like these explainer videos even more. I especially like connecting the engineering issues with the policy issues.
I like it too -- they're harder to make, partly because the graphics are more time consuming, but also the amount of time I have to spend thinking through and triple checking all my calculations. I'll definitely make these kinds of vids a regular feature though.
The idea of congestion pricing sounds very interesting. Is there a country that has a similar policy already in place so we could analyze the effects that it has on transit? Also, I might have a video topic suggestion. I noticed you mentioned Montreal in a few videos, like in the city pairs for high speed rails in North America and high speed rail vs air vs car, Canada edition. I was wondering if you would be interested in doing a video on Montreal's city planning/transit, and what are some of the ways it could be made better. I have a hard time finding articles on that topic. Lastly, I want to thank you for creating this channel, I have been enjoying the content a lot and I'm looking forward to your future videos!
@@kevinlove4356 Thanks! Yeah, I was going to say, Reece (@RMTransit) does a great job covering Montreal, especially recently! I'll keep your idea in mind, though.
That was mind-blowing! And with such a simple and graphic explanation! The only thing that was missing IMO, was showing us the car pile-up with >160 cars in the bar diagram, that would have been fun!
Very interesting. It really goes to show how important public transport and bike infrastructure are, when you can just get say 20% of the cars off the road and reduce congestion by half.
This is excellent stuff, as a current resident of one and former resident of four other top 11 metro areas in the US, the key to all of my public transit willingness is how big the difference in time is between driving and other modes of transportation. Of course there are days I drive instead of bus/train if I had other errands that day, but traffic congestion factors like this one are a huge influencer in commuter decision making. This leads right into your content on bus only lanes and why metros or commuter trains that aren’t at the mercy of freight are critical. The real question is how much time is saved or at least roughly equal to take public transit (or carpooling) versus driving and being stuck in intersections like this one.
suggestion: give it a "drop arrow" where they are forced to give way to oncoming traffic in peak times, that will back it up even further, like.. way further then people will need to find alternate routes which in turn reduces the traffic because they are choosing alternate methods. But alas, the engineers decide to extend the green and add another lane, adding to the overwhelming chaos that ensues, construction recently finished on a right turn where they added a lane (Australia) doubling the capacity inside the lanes, how long do you think it will last before it will become congested again? Another example is on the same road, they extended the right turn lane about an extra 50 meters (enough to fit 8 wagons) how long do you think that will last? People used to take alternate routes rather than being stuck in traffic, how long will it be before they are content with being stuck with a lineup that will take 3 cycles to get through when you are at the back of the line? Sometimes it's best to either have a drop arrow as I stated, or say outright "no right turn between X and Y times of the day."
Really shows how car pooling and taking transit makes a difference. Great video. I don't get why all these city planners suggest fees though for driving. That's not really fair as it punishes the poor and those who don't live close to where they need to be.
As a former resident of Southwest Florida, I can confidently say that adding additional lanes in order to alleviate congestion is definitely a cheap and reliable way to make sure there are never any delays and that every driver is happy and calm. **twitches**
@@CityNerd I lived on Sanibel when I was in high school and was able to move back with my family for a few years. Sanibel is really lovely, and they've done a good job of keeping the commercialization to a minimum. I remember the "McStop" campaign of the mid-90s, when McDonald's wanted to build a restaurant on the island and made all these modifications to the plans to adapt it so it would blend in, but the residents kept it from happening. The only chains are Subway and Dairy Queen, and they were there before the city was founded in 1974.
That's why you should plan your route to minimize time consuming left turns during rush hour. Not to mention that making a left turn puts you at higher risk of getting involved in an accident. There's a reason why UPS instructs drivers to avoid left turns like the plague.
Can you do a video comparing Level of Service and Vehicle Miles Traveled? I've heard that they can be used in place of one another when looking at road projects or proposed developments in an area. It seems to me that each metric measures something very different.
They are very different. State of California is the leader, I believe, in moving transportation impact studies from a LOS focus to a VMT focus. I'll add it to my topic list!
I really liked the explanation. Easy to understand but not going into the mind-numbing math behind the scenes. It’s not rocket science but like you said, it’s not linear either.
![Stroads are Ugly, Expensive, and Dangerous (and they're everywhere) [ST05]](http://i.ytimg.com/vi/ORzNZUeUHAM/mqdefault.jpg)
This is probably the best explanation of this phenomenon that I've seen. I'm going to refer to this in a future video for sure.
One of the most frustrating "objections" when it comes to alternatives to driving is that many people need to drive, and (today at least) there may be few people who can take advantage of these alternatives in a car-dependent city. It's annoying that this "objection" ignores future travel demand, but it's even more frustrating because you actually only need to take a small number of cars off of the road to make a hugely positive difference to congestion.
You didn't quite say it in this language in this video, but you hinted at it: the difference between free-flowing traffic and stop-and-go traffic can literally be just a few cars. Which means that even if, say, a dozen rush hour drivers cycle instead, it can have a massive contribution to better traffic flow.
I recently made a video about how driving is awesome in the Netherlands, but I have a feeling that most suburbanites are never going to understand this.
Edit: by the way I searched for lazer dix on my channel and he's a car enthusiast who was triggered by my noise video. Some of these people do not appreciate being reminded of what the damage their "hobby" causes to society, and when somebody does, they try to paint them as irrational car-haters. There will always be selfish people who want to stand in the way of progress, but that's why we need to keep fighting for better cities.
There's really three dimensions to changing car-brain: buildings, streets, and vehicles. We need to show them how all three work together to make a new living space.
Zoning, street design, and new vehicles they may not have heard of like e-bikes, cargo bikes, trams, light rail, and others are part of a great urban landscape.
@@lazerdx wow you really got burned here, lol
@@lazerdx bro, everything is politics. Wake up.
@@lazerdx Wow. Keep your shirt on pal.
Maybe 'Not Just Bikes' is not professional enough for you but he's often humorous and gets his point across in a non-conflicting manner.
Which is more than can be said for those who fly off the handle (bars). 😆
@@pappy9473 The quality of his content is not what I was complaining about in the slightest, and for the record his passive aggressiveness in comments makes me look like Mother Theresa (the idealized version, not the real one).
"You are the congestion." That might be the single biggest eye-opener here.
It's a time-worn phrase in transportation planning circles, but it's true enough to justify big font.
So make the cycle eight seconds. Duh.
This is your best one yet, by far. I'm sure these kinds of videos take significantly more effort than the top 10 lists, but this is the one that made me subscribe. Keep it up!
Thanks, I appreciate it!
Same for me!
agree
@@CityNerd Does it actually require more effort than a top 10 list? With the research you put into those lists, I wasn't sure..
@@CityNerd I would love to see a video on how commute time affects lower income families as they get pushed out of the city centers. It's a serious problem in cities like SF
I used to take an exit in Mountain View (101 N to Shoreline N) that would back up at the light from 8 am to 11 am, and let through ~30 cars a cycle. I once (while siting in the traffic) figured out that every car that decided to use the exit caused a car after them to miss a light at EVERY traffic cycle, which was about 2 minutes long. If a car showed up at 8:02, the next 90 cycles would each have one car shifted to the next cycle, and therefore be delayed by 2 minutes. That works out to 180 minutes of delay PER CAR!!!
Congestion is non-intuitive...
I usually showed up around 10:30, so I was only delaying a few cycles after me, but this realization strongly encouraged me to take my bike.
Excellent point and explanation.
It's amazing and crazy that this is the actual transportation system we rely on, when you really think about it.
When I was a kid in the 90s my central Mexico hometown started building more road infrastructure like overpasses and interchanges, when the city was about 500K inhabitants. My relatives joked that all those new bridges were excessive for our "small" city.
Now, 25 years later, the city is over 1M inhabitants, lots and lots of viaducts and underpasses have been built, most of them on the access roads to the city and the ring roads, however when a new underpass is under construction it always gets messy. Public transport was and still is lackluster, so even working class people bought cars to move around. It has just gotten worse. I recall my childhood years of empty roads, they're gone. I don't know if the civil engineers are in bed with the local government or the fact we have the largest Nissan plant on Latin America has fed the car culture.
I happened to go visit Aguascalientes twice in 2007 -8. I liked the idea of the city rings, but even then, traffic congestion was almost the same as here in Mexico City. I blamed then the climate, since there was in the raining season and wrre a couple of stoms that made a real mess in downtown... Three blocks walking along a flooded road to cross it to walk back to downtown Steren...
That's the story pretty much everywhere: build roads and there will be cars and traffic and chaos. Build active/public transport, and people will move quietly and efficiently.
Whichever country America has a influence it is more car centric except countries who still build public transport
Queretaro?
That first possible solution is more or less the one everyone think will work: "1 more lane will do the trick!"
It just makes the cities even worse for pedestrians with massive stroads and these intersections so large that even with pedestrian traffic on crossing it is basically suicide.
And the adding one more lane also runs into the issue of induced demand. The easier it is to make a particular journey, the more people make that journey. So you add one more lane, then find that a couple of years later the congestion is just as bad as it was before because the extra lane means that more people are driving on that particular stroad.
it must be a bike crossing to not commit suicide
I can agree. I have to cross 8 lane road and it scares me
This is also kind of why airport security lines (for example) appear either empty or backed up significantly. When the system is at or just below capacity, all is empty. When it's just 20-30% over capacity, it's 100% lined up.
Another good example! Someone else mentioned elevator banks at peak demand.
It has been my experience that cities which have successfully eliminated or seriously reduced traffic congestion have used none of the solutions mentioned in the video. Instead they have implemented measures that make walking, cycling or public transit the fastest, easiest and most convenient way of safely going from A to B.
I will give three examples. The first is Groningen in The Netherlands. This uses a neighbourhood zone strategy. This means that people walking, cycling and using public transit can go straight from A to B. But concrete and steel barriers prevent private automobile drivers from going directly from one zone to an adjacent zone. For private automobile drivers to go from one zone to the next, they must drive out of the zone to the surrounding ring road. Then drive around the ring road to the outer edge of the zone in which their destination lies. Then drive in through the zone to their destination.
This has the effect of making walking, cycling or public transit the fastest, easiest and most convenient way of going safely from A to B for a very large percentage of trips in Groningen.
The second example is Ghent, Belgium. The introduction of its Traffic Circulation Plan put affected streets into three categories.
Category 1 Car-free.
Category 2: Motor vehicles are restricted to local residents, local merchants and their suppliers, public transit vehicles, taxis and emergency vehicles.
Category 3: A neighbourhood zone strategy, similar to the above one for Groningen.
Ghent's Traffic Circulation Plan resulted in rmaking walking, cycling or public transit the fastest, easiest and most convenient way of going safely from A to B for a very large percentage of trips in Ghent.
The third example is the city of Utrecht in The Netherlands. It has an extensive car-free downtown. The motorway that was built upon the city moat was removed and the moat restored. And on other streets, there has been a steady shift in use that took away space that was previously used by motor vehicles in order to create fantastic cycling infrastructure. Once again, the effect has been to make walking, cycling or public transit the fastest, easiest and most convenient way of going safely from A to B for a very large percentage of trips in Groningen.
I strongly disagree with the statement: "Every city has problems with growing traffic congestion." These three cities do not, and neither do many other cities around the world. The one thing that they tend to have in common are measures that make walking, cycling or public transit the fastest, easiest and most convenient way of safely going from A to B.
I highly recommend Mark Wagonbuur's blog, "Dutch Cycling." It provides an excellent description of Utrecht and many other places in The Netherlands.
True! You can't just make driving less accessible with congestion pricing without delivering better infrastructure for the alternatives. Also, cars are just an extremely space-inefficient mode of transportation that's not suitable for cities because of the limited space available. Every city where the main mode of transportation is cars will have congestion issues. The solution is using more space efficient modes of transportation.
@@lb2791 Very true. In cities where the main mode of transportation is the bicycle, it would be impossible to start using automobiles for transportation. The laws of geometry dictate that there just is not enough space to put that many large metal boxes on the street.
It is annoying that RUclips no longer allows me to post links. Mark Wagonbuur has produced an excellent video of Vredenburg in Utrecht for his "Bicycle Dutch" blog. This street is used by 32,000 people on bicycles each day. It would be impossible for them to start using automobiles. Just not enough street space. Or space for automobile parking.
One of the most fascinating parts of the video is the "before and after" shots. Before the street went car-free, it was a nightmare of congestion. Now traffic flows freely.
Please search with RUclips's search function on "Bicycle Vredenburg."
ruclips.net/video/gOl5vF8l7Fc/видео.html
Great example! A car lane could move 1/20 of that amount in people.
@@lb2791 Also see:
ruclips.net/video/ynwMN3Z9Og8/видео.html
Hey! My link showed up!
I really appreciated the graphic representation, helps explain something that would otherwise be quite abstract
I didn't think I could do this adequately without some decent visuals. Thanks for the appreciation.
Now I'm curious how a similar analysis for a roundabout intersection plays out.
I’d be interested in a video on Carmel, IN which is a suburb of Indianapolis that is known for its roundabout obsession. Ironically, it is home to the nation’s first stoplight.
Great idea. Would love to see that
Carmel, IN is super interesting. Check out Bend, OR too! Roundabout analysis is a lot different, but it tends to break down later for a lot of movements. Tradeoffs with amount of land consumed and bike/ped integration, too, of course.
Roundabouts are interesting when considering their failure modes. Roundabout evangelists often insist that roundabouts are the solution to everything, but there are cases where they fail hard, particularly in asymmetric traffic volume scenarios. If a roundabout has signals, it has probably reached failure point, at least during some portion of the day.
An analysis of the situation would certainly be interesting. Also compared with an all way stop, which seem to be everywhere in my neck of the world. (No, all way stops are not the solution to everything, either. They're used around here in many cases where a roundabout would be better.)
Roundabouts are worse; when they fail they fail hard.
Would love to see a video detailing “smart” traffic lights in the US. The one for my street seems incredibly dumb, like it is only programmed to ever save time on the busier cross street rather than consider the actual traffic conditions at the time.
My street is the exact same way. I've seen it red for me while green for an endless stream of nothing even though it is "smart"
@Zaydan Naufal is it that much more expensive? If traffic flows better there is less stress from it, people will be less tempted to drive through a red light, and people have more time to spend wherever they are going.
If the costs of a smart traffic light are higher than the returns from it I would wonder if a traffic light is the smartest thing to have in that place.
Yeah, my theoretical traffic signal here is slightly dumb -- you would hope that there would be an algorithm behind it that occasionally allocates additional time (recovery time) to over-capacity movements.
@Zaydan Naufal cctv and speakers? that's not expensive at all
Road Guy Rob does an excellent video on traffic lights and their sensors and cameras.
This is a great explanation, but as a math/cs professor, I have a quibble: this shouldn't be described as exponential growth. The effect is clearly super-linear, but would be better described as quadratic (x^2) than exponential (2^x). The effect here is quadratic because each additional car ADDS time that grows with the number of cars; exponential growth would mean that each additional car MULTIPLIES the time by a constant factor, which would have a much, much bigger cumulative effect. In this context, either quadratic or exponential would be bad, but in other contexts (like disease spread) there's an enormous difference between these growth rates!
I'm with you -- but that terminology doesn't scan on a video thumbnail!
i like how tight you edit your episodes. not a word wasted in 12 minutes. Impeccable!
I would love to hear more about congestion pricing! I live in San Diego, and our grand transportation plan just lost its mileage tax provision because the city council cut it due to public opinion/messaging. Now the city's big goals on many things--including multi-modal transportation upgrades--are possibly not paid for in the long run... developing story!
Congestion pricing is so massively politically fraught. I'll definitely make a video soon, but I just have to figure out what angle to take on it.
I'm no expert but it seems like tolls and the like mostly serve the wealthy. Any additional pricing on drivers is going to push more people into poverty, which is already at crisis levels. Maybe use it to help push middle class folks to bike & rail networks once you've made those viable choices, but at that point it's probably not necessary.
@@NickCombs Exactly. These kinds of schemes are regressive and hurt the poor the most. The well off don't care about having to pay more to drive to work (or more for gas in the form of a "carbon tax") but it can be a severe burden on those on the margins who just want to go to work.
@@CityNerd Here in New York City, the CP plan hasn't yet been developed, but I suspect that nobody trusts that whatever money is raised via the fee will go to where it is supposed to go and also that whatever money does get to its destination, it will be spent inefficiently. I await your video on CP. BTW, you've gotten another sub as a result of this video.
@@NickCombs That is why you have to make sure that there are good and reliable alternatives (mass transit for instance) before you do this, which is why this can't be a measure on its own, but has to be part of a larger plan. And also the price doesn't have be massive. See what Stockholm did for instance. I don't know the exact numbers, but the price was not high and it had a massive effect.
Traffic congestion, like other issues related to city/community life, requires a unified, system based approach. Number of car trips is related to number of dwellings and to work/school/shopping locations and is closely linked with income. (not everyone can afford to own a car) Part of our challenge is that all these factors are viewed/managed by separate agencies/interest groups. Lack of unity is an overall limiting factor as regards mitigation of problems or improvement of the quality of life.
The number of car trips is also related to where people live in a city. For example, those who live in the downtown car-free zone are unlikely to own a car.
@@kevinlove4356
Wish this were true.
Desire for route,
Increases directly compared to
number of people involved.
Regardless of where, these numbers follow similar patterns.
-- Have you ever tried to park, downtown ?
Obtain twor forms of grid-lock !
-- Numbers of vehicles,
-- Numbers of people wishing to use the mass transit system.
Interested to see if this compounding effect is apparent for freeway lane closures, and the effect that more lanes of traffic get better or worse with the same number of lanes closed
Interestingly the opposite was observed during the viadoom “carmageddon” in Seattle when the closed the viaduct but wouldn’t open the tunnel for another 3 weeks. The city added a bunch of transit options, including more water taxis, encourage people to work from home etc. and it worked. Traffic did not increase significantly during the closure.
Ironically the missing carmageddon following the viadoom was used to demonstrate that Seattle doesn’t really need a waterfront highway. You can literally close a major highway and enact policies which eliminates the traffic. Sadly policy makers have yet to learn from this in Seattle. The tunnel is now open and they are in the process of building a major arterial road above it (see also West Seattle bridge fiasco).
It does. It's also the reason some freeways use signalized entrances to slow the introduction of cars to the freeway. By stopping just a few cars you can make the congestion go away.
Analysis of "interrupted flow" (signals, stop signs) facilities and "uninterrupted flow" (freeways) facilities is completely different -- different enough that they warrant totally separate volumes of the Highway Capacity Manual! I may do another version of this video in the future looking at freeways instead.
@@CityNerd Here is a video idea: “Top 10 carmageddons that never were”, a list of high profile highway closures which predicted a bunch of extra traffic, bu only a fraction of-if any-increased congestion was realized.
As a delivery driver:
I can assure same teaffic congestion for any temporary route changes.
Avoiding the peak congestion times,
Quickly reduces delivery times.
Because of this: I refuse to do deliveries during peak times.
( 2 hours in a.m. AND 2 hours in p.m. )
Since I only derive utility from sitting in traffic, this is the best news I have ever gotten.
I will watch the rest of your videos while driving around my F150.
*I* am the congestion.
Thank you for normalizing that it's OK to be an advocate for active transportation and transit while also thinking that congestion is bad.
Transit and cycling are the way to eliminate congestion. Look at what is happening in Paris, France.
That's my new channel catchphrase: "Normalize Normalcy"
Been driving for 40+ years, professionally for 13+ of those years, and I would argue that 60%-80% of traffic problems (particularly on freeways) are due to a small percentage of 'oddballs' - people who don't (usually won't) conform to surrounding traffic. While they're halfway tolerable when congestion is minimal, a single oddball can potentially shut down an entire freeway if traffic is at least half of the design capacity.
The first mantra of professional drivers is "go with the flow". It's almost hilarious when some looney flies past me going ±15 MPH faster than the rest of traffic, weaving between lanes (usually without a single turn signal), only for me to pull up alongside them at the next traffic light. The same happens in the opposite direction when someone insists on driving slower than the rest of traffic, particularly when they do so anywhere other than the rightmost lane. Even then, it doesn't take long before other drivers become more prone to take undue risks in order to switch lanes and get around the oddball.
When traffic is light, the impact of either extreme is negligible - there are plenty of opportunities to change lanes at minimal risk. But as soon as congestion begins to build, changing lanes (especially if going a different speed than prevailing traffic) becomes exponentially more dangerous. Furthermore, drivers who are overtaken at speed have a tendency to panic and reflexively hit their brakes; seeing brake lights ahead, the next driver hits their brakes (likely harder than the person ahead of them had), etc. You very quickly have people slamming to a complete stop in the middle of the freeway for no reason whatsoever. Which means that someone is likely to switch lanes suddenly, bringing adjacent lanes to a screeching halt as well, expanding to include the entire roadway - sometime even ensnaring oncoming traffic in the process.
And all because ONE driver insisted on going 10 MPH slower than everyone else on the freeway.
As someone who lives in Fort Myers and has taken the intersection shown in the video hundreds of times, the solution shown does not work even though it looks nice.
That intersection does not get congested often, but the left turn wait times are heinous for all turn lanes. Usually 3 minutes or more between cycles and so when it does get congested during our tourist season people are left waiting 7 or 10 minutes to turn left onto 41. And therefore it’s my most despised intersection in the city.
Funny to see it on here, your best video yet!
I actually included it because I stayed at a hotel like a block away from there and that intersection (and land use context) just blew my mind. The cycle lengths are atrocious. Exhibit 1A when you value volume/capacity ratio as your performance metric over everything else. I still had a good time in Fort Myers, though! Baseball and beach time in Feb/Mar can't be beat.
Could you do a video talking about how citizens can help influence public policy in their own cities around issues such as this? Congestion pricing sounds like a great idea, but given how the recent attempt to implement a parking management systems (paid parking) in my own city was received by the population, it sounds like it would be a really hard sell. Not saying specifically to do a video talking about how to get congestion pricing implemented in a city, but how to advocate for positive change in regard to urban transportation. Maybe a top 10 examples of times urbanist advocacy groups made stuff happen in cities in North America and how they did it?
Conventional advocacy is not my wheelhouse (my background is consulting), but I have massive respect for the people who are good at advocacy and navigating the political system -- and I know a few of them. Let me give this some thought.
This would actually be extremely helpful.
Raising costs is only going to punish the poor, and create a road class system, like we have a housing class system. We already have enough toll roads. There are many other things to try first. Sure public transport is a good option for some people, but how about incentives for people to ride a motorbike or scooter?
@@tubester4567 my city tried to incorporate congestion pricing too but it immediately got labeled as a money grab by the government and it hasn't gone through. I would agree that it will def hurt the poor more. Subsidizing their cost based on their income might help but then things get complicated and you have more paperwork and forms to keep track of as a citizen. My other question is how else can we fund public transportation or other modes of trransportation? Any move on trying to collect money for the betterment of the whole community leaves people angry. Americans hate getting taxed. So what's the solution?
@@shreyas9701 I am not an American nor living in America. After watching all these videos, my understanding is, you guys shall fix the city planning and zoning first. Before single family houses reduce to a certain percentage (which may never happen as it is a cultural issue), the immediate traffic fix is NOT congestion pricing. The band-aid is encouraging e-bikes and e-scooters for rush hour job home travel. They are fast enough to ride on the motorway and they are far smaller in size so the same road can pack a lot more of them. Then the next step may be to build railway lines that allow people to ride / bring their bikes / e-bikes / e-scooters onto the train and travel with them. Now the bikes and humans are more closely packed and move even more efficiently.
I work as Vertical transportation consultant (read elevator guy) and I can relate to this 100%
OOOhhhhhh, elevators are such a good analogy. Corporate office building elevators at the lunch hour!
This is one of the factors, but a really significant one. Other factors contributing to exponential growth of traffic also include these:
- Land use: as cities sprawl more and more, the average trip length grows. Each trip then contributes to congestion along more portions of the road network. Suppose you have an arterial with signalized intersections every kilometer. Someone living in the inner suburbs 5km away would likely affect up to 5 intersections; but someone living in outer suburbs 10km away would affect up to 10 intersections, if they're heading to the same city center. All of the congestion-causing phenomena effects mentioned in this video manifest at more places, generating gridlock.
- Induced traffic demand: believe it or not, people have a surprisingly high tolerance and flexibility for congestion. If a major route has its capacity increased through geometrics (ex. more through lanes, more turning lanes at intersections, grade separations) this reduces travel time in the short-term. The effect of this is people who were using strategies to avoid congestion (alternate routes, alternate trip times, carpooling, alternate destinations, trip avoidance transit as a back-up option when they'd rather drive) will pour into the main route, and them vacating the alternate route attracts more trips elsewhere. In the long-term, the expanded capacity makes long-distance trips more attractive, encouraging sprawl.
- Traffic incidents: situations which obstruct traffic can have an outsize effect on congestion, such as car crashes, disabled vehicles on the roadside (or sometimes in the lane if there's not enough shoulder/berm space available), inclement weather and so on, will create localized disruptions to the traffic network. Add up enough of these, or do just one of them on a busy route, and this will propagate congestion big time. There's also a risk of secondary traffic incidents caused by the initial incidents, which may mean the first incident's effects alone can create a prolonged disruption.
All great points. Thanks!
I'd love to see a video on how to make congestion pricing work on surface streets.
I think that's the thing that really gets me about autocentric transportation planning. The only thing that makes it viable is a roughly static number of drivers driving a roughly static distance, and socioeconomically speaking, the justification for pouring all the resources into that type of transportation development is essentially that the economy will always be growing and more people will always be driving more.
No. The justification is that people are traveling to work by car of their own choice. Usually from a distance several towns over or longer.
@@GeorgeMonet You're assuming that people are living so far away from their work by choice. Restrictive zoning laws--both against higher-density residential and mixed-use zones--means there's no reason to assume that's true.
Exceptional video! One thing to also keep in mind for perspective on the inefficiency of cars is that each cycle in this example there are ~7 people moving through the intersection.
Most likely -- unless it's on a bus route!
This is great! I wish I could share this on my local Facebook community group and that people would actually get it... instead of constantly demanding local reps try and make their drive smoother, instead of considering alternatives.
It would be amazing to see you tackle all this issues with Cities Skylines. It would be so interesting to watch you build your own city, with public transport, traffic and motorways. You should try it!
Oh man, I'm a recovering gamer. Don't make me backslide!
You can balance it out. Doesn’t have to consume your life lol
Really enjoyed the video, getting into the math is really interesting and I think you could even cover more advanced or complicated math. The graphics were really helpful, how do you make them?
I would love to see a video exploring congestion pricing along with induced demand, and the effect (or lack thereof) of transportation alternatives on congestion!
I'll definitely do a video that goes deeper on congestion pricing at some point.
One other thing that can compound the aforementioned inefficiencies is bad weather/road conditions (especially when you're like me and driving in Canadian winters)
Since cars take longer to accelerate and have to be slower in general on ice, road capacity can be temporarily reduced and cause the same exponential traffic jams.
It can pretty easily turn an otherwise normal intersection into waiting 20+ minutes for a left turn...
Great point.
Great video. Also, I want to add to the voices encouraging you to do more along these lines, in terms of video structure. The top 10 lists are entertaining (and possibly useful for somebody considering a move), but stuff like this is way more interesting and rewarding.
Loved the video. I personally have to say I do enjoy these kind of videos more than the top 10s (which are still very interesting) and I really would be delighted to see more theoretical videos in the future. One completely unrelated thing, I was wondering if you could maybe do a video on the public transport system in Karlsruhe (Germany). I find that an very interesting one because
1. The city isnt really big, and it's always interesting to see smaller citys develop public transport systems.
2. It is an early adopter in multy system trains with trains running on the normal tram Tracks and the Deutsche Bahn Tracks even running on the same tracks as the ICE (high speed rail)
3. They just finished a huge infrastructure projects with an downtown city Tunnel which replaces trains running through the pedestrian zone.
4. The network is huge for a city that size with trains running from the city centre to quit remote places in the mountains (Freudenstadt is 80km away)
5. The system grew extremely nicely by using existing tracks which where underused and is completely electrified
6. It kind of shows that quite good service can be given to very remote region's
I don't know if you would be interested in this system, but I always found it very interesting especially as an model for city's which may be interested in improving there systems cheaply.
I definitely want to do videos that explore German transportation systems and ideas. Lots to learn from there!
@@CityNerd
Btw. If you need help with translations, feel free to ask.
Great video and I loved all of your visuals!! Super helpful explanation
Wow! What a great video.
Keep it up man!
I just recently saw your videos. I love it, it’s way in my interests and I’ve subscribed and talk you up regularly. For me, it’s really eye opening that a very few people making different choices can massively improve things. I’ve taken to doing a fair bit of my work transportation on a commuter train with a scooter or EUC to and from the station, and lots of my local errand trips on an ebike. People really don’t recognize what removing traffic lights from your trip accomplishes. Many of my trips are faster than driving. This is in the DC suburbs. Great work!
Excellent video, I write you from one of the most congested cities in the world, Bogota Colombia. I love your math and technical take on this issue, that is the non trivial explanation we all need for the exponential nature of traffic jams. In what concerns solutions, the main ones are to pay for congestion (i.e. to make one-driver cars a very expensive privilege) and to have massive, humane, accesible transit in particular, metro lines. Greetings from Colombia and excellent content!
Please keep making these videos this is more addicting then car-centric development in North America.
I was randomly thinking about that yesterday, and here is the answer. Thank you!
Great video as usual! I love it when videos reinforce what I'm learning in my classes, and this works through a lot of what we covered in doing a corridor study (things like modeling queues and the impact of implementing tolls with a transit cross-subsidy).
Good to hear!
Wow, this was an awesome video! I really can tell you spent a lot of time on this, especially the graphics. What did you use to make those?
I'd love to see more of these style.
Exciting to see this channel growing!
My graphics studio is top secret! I have a crack team of underpaid keyboard jockeys sequestered at a Black Site, toiling away with limited food and water on hand. Need-to-know basis!
@@CityNerd is it perhaps your own children being put to work? 😂
I always value that you respond to comments, it adds a lot to these videos.
Couple ideas for future videos:
1) Top 10 (or bottom 10) cities in terms of the condition of infrastructure. As a San Francisco resident, I'm consistently shocked by the condition of the roads here and how the city (and state for that matter) completely shut down any time it rains. I feel like other cities handle much worse weather far better.
2) Does it take longer than it used to build big projects in the US, and if so, why? Again, as a CA resident, it seems like even simple projects, like adding a BRT Lane to Van Ness, take an incredible amount of time to complete.
Honestly one of your best videos. Needs more views.
Great video, very informative. I'd love to see your take on how best to implement congestion pricing and where/when it would be necessary.
Good video...but I actually think a better way to illustrate exponential congestion is with on/off ramps as opposed to traffic lights. The problem with a freeway is there is a finite space-time window to enter/exit a freeway via the far right or far left ramp. So a 10 lane freeway doesn't have 5x the capacity of a 2 lane freeway, because the cars can't use the lanes equally. Each lane change creates slowdowns for traffic behind you, and many vehicles have to stay close to the exit lane to get off...which in turn bottlenecks the cars trying to get on. On top of this roads take up a lot of space which results in lower density development and forces longer commutes. A final thought experiment to prove my point...would a 100 lane freeway still suffer traffic jams? I would argue yes, because the ramps and not the lanes are the bottlenecks most often. I actually think a 100 lane freeway would be a good video topic to prove many concepts.
-- Might wish to start with:
Autobaun (sp??) In Europe..
?? Where are it's greatest problems ?
As usual, a great video. If only we had more planners and engineers in the system that grasp how transport works like you do
I truly believe that most of them do grasp these problems, but their hands are tied.
@@stevengordon3271 I think that's accurate. Or, they know, but it is just so, so , so much easier to just do the same thing you did last year, or ten years ago.
@@stevengordon3271 most of us (engineers) do understand the problem. But getting clients (cities/counties) to buy in is tough. They come to us with a single congested road, and want it to handle more traffic. They'll hire another firm for the job if our proposal is to invest in bus route and bike lane expansions.
@@FrontierBill In other words, "your hands are tied".
@@stevengordon3271 in an oversimplification, yes. I wanted to get across that, in general, the project isn't as vague as "improve traffic". By the time it gets to a transportation design consultant, the client has defined the project more narrowly as "come up with ways to add a lane to improve traffic throughout". The most leeway we get is in how we arrange lanes or handle parking.
Coming back to the city with a recommendation to improve transit to reduce traffic demand is not addressing their actual project.
Now the place where we can make these recommendations is if you get a contract for something like a city masterplan. In that, you can push for investment in transit to mitigate future traffic congestion.
Awesome video! I’ve always had trouble explaining these types of congestion scenarios to friends/colleagues but this is the clearest I’ve ever seen it explained. Will definitely be sharing this video to others instead of trying to explain this myself!
Share away!
Very clear, important info. Thank you
Wonderful content. I really appreciate the effort in these and look forward to a congestion pricing video
Thanks a ton! I also would love to see studies about how likely people are to be on their phones not paying attention and the like at various levels of cogestion - I feel like observing other drivers anecdotally (and myself) suggests that not only is it more likely for there to be a person doing that, but everyone prone to doing that is more likely to do so the more congested (and thus disengaged/frustrated) drivers are
So glad that I've found your channel; you have lots of interesting videos related to urban planning, especially on transportation! Can't wait to watch your past videos!
This is probably one of my favourite of your videos, the mathematical explanation of traffic phenomenon is great
Fantastic video. I'll certainly share with folks anytime I have an argument about solving traffic congestion!
Fortunately all of my countrymen understand math, so they are all in with this.
The hands down discussion of congestion is a brilliant piece of work.
Best math explanation imaginable, concrete and accessible. CGPGrey like brilliance.
Great, I've been waiting for this one since you teased it a while back!
Brilliant presentation. Quantitative analysis always convinces me more than hand-waving qualitative arguments.
I remember like 2 months ago you were celebrating 1K subscribers, now pushing 15K. Great work!
🎉
Not so sure about congestion pricing, but parking pricing - definetely yes. The ideal situation is where you have a car at home (if you want to own one), but the parking at your destination is expensive enough so that you don't actually use it.
Now you might ask why own a car if you wont use it. My experience tells me that public transport is almost impossible in rural areas, forests, minor intercity routes, etc. And I do road trips a lot. At least one kind of lifestyle requres a car even if not using it in the city for everyday transport.
Yeah, to me "congestion pricing" is an umbrella term that includes a lot of potential strategies, cordons, tolling, VMT pricing, and definitely parking. I'll discuss more in a future vid.
I love hearing this kind of analysis. Thank you for this peak into your chosen field.
I am a Practitioner of Traffic Aikido.
At the root of my traffic driving is AVOID RUSH HOUR.
SECOND is the MANTRA, FAST IS SLOW AND SLOW IS FAST.
MEANING... don't ever exceed the posted speed limit. And...drive closer to the mean speed during Rush Hour including in the calculation the time standing at intersections and or jams and not moving. So, that means in a local road with a 45 mph posted speed limit, I will try to dive NO FASTER than 37 mph and slow down well before Red lights to attempt to avoid complete stop of my vehicle.
This directly confronts the prevailing Race to the Next Red Light mentality. Not only do these cars seldom "beat" Yellow cautions indicators, they often run Red lights which is one of the most prevalent causes of car collisions.🎉
And iif they stop, wait the 120 seconds to race off again, often I roll up along side them just as they start to move.
It's counterintuitive.
But it works except it elevates my chance of being a victim of ROAD RAGE.
You know what they say? Lead, follow, or get out of the way.
Mostly I choose GET OUT OF THE WAY.
I'M NOT AS STUPID AS I LOOK.
Fantastic video! Great insight! Love the technical outlook on the problem!
I live in London (UK) and the congestion charge definitely helped matters but I don't think it's gone far enough. Congestion is still terrible, despite having a great commuter rail system and the Tube, I still see a lot of single occupancy vehicles driving into the city every day. I think the zone needs to be enlarged and charges increased further. I say this as a driver. I drive into the city (occasionally) for work because I have to (I carry a lot of gear in my car, which I couldn't take on the train or bike), but I see many people who really don't look like they need to be in a car. If the charge was higher, a lot of those would go and things would get better for everyone else who have to use the roads.
I don't know if I'm up to date on the London cordon zone. Has it expanded or contracted recently? Any recent studies on pricing/volume? I think the pricing structure and geography need to be revisited regularly to keep it useful and equitable.
@@CityNerd There was a western extension that was removed about a year after after its introduction. I think it should probably come back. Recently there was a new Ultra Low Emission Zone (ULEZ) introduced (a toll on gas guzzling vehicles) but my anecdotal experience so far is its made no difference. Perhaps time and official data will tell the full story.
I'm curious about the impact on lower income individuals who can't pay the extra fee? My city tried to implement this but it got shut down immediately and was labeled as a cash grab by the government. I should mention I live in America and all Americans hate taxation. But without some sort of tax how can we even start funding for better public transportation or infrastructure for bicicyle lanes etc? Not to mention how car centric and difficult it is to go anywhere without a car. So it's not fair to force people to not use cars when we don't have good alternate modes of transportation but we can't get alternate modes of transportation without a tax. It's like the Catch 22. sigh...
@@shreyas9701 Yeah, the U.S. is a bit screwed in that sense. Over here, if you can't afford it, you just walk, bike or take the train. I think probably the key in the U.S. will be to densify development in certain areas, with mixed use zones and develop walking and biking (and eventually transit) around those areas, and make sure that's where the affordable housing is located.
@@mdhazeldine right- it sounds impossible to try to get any mixed use urban planning done. Everyone loves their car and single family homes too much 😭 I might just move to a different country. Nothing is gonna change in America anytime soon.
One of the best explanations of this topic!
This is the best and most important video on the internet.
The visuals are awesome, thank you! Makes it much more understandable. :)
This was an incredible clear and well explained video!
Really enjoyed this video and felt like I learned something!
So glad you made this video! I enjoy all your videos but I would like to see more theoretical videos like this
Excellent! This is a great micro analysis on how cars on the road effect one intersection. I wonder what kind of study there has been on the macro level of congestion. When each car causes exponential growth of delays, the whole system is going to be strongly effected by the average trip distance. Does 1/2 the number of cars traveling twice the distance cause the same amount of congestion? This has huge implications for suburban growth and development patterns.
Long story short: yes. Cara travelling through lots of intersections will use the capacity of these intersections. Shortening trip length world indeed reduce congedtion.
Source: I am not a professional, I just play cities skylines.
Your top 10 videos are good... But I really like these explainer videos even more. I especially like connecting the engineering issues with the policy issues.
I like it too -- they're harder to make, partly because the graphics are more time consuming, but also the amount of time I have to spend thinking through and triple checking all my calculations. I'll definitely make these kinds of vids a regular feature though.
@@CityNerd That makes sense... Consider this a note of appreciation for your hard work.
Love the more theoretical videos! You bring awesome information to the table! Keep it up
Will do
The idea of congestion pricing sounds very interesting. Is there a country that has a similar policy already in place so we could analyze the effects that it has on transit?
Also, I might have a video topic suggestion. I noticed you mentioned Montreal in a few videos, like in the city pairs for high speed rails in North America and high speed rail vs air vs car, Canada edition. I was wondering if you would be interested in doing a video on Montreal's city planning/transit, and what are some of the ways it could be made better. I have a hard time finding articles on that topic.
Lastly, I want to thank you for creating this channel, I have been enjoying the content a lot and I'm looking forward to your future videos!
A lot of european cities have a congestion charge to access the city center by car
RMTransit has many videos on Montreal.
@@kevinlove4356 Thanks! Yeah, I was going to say, Reece (@RMTransit) does a great job covering Montreal, especially recently! I'll keep your idea in mind, though.
Topic suggestion: My city of Zurich has decided to switch all downtown roads to max speed 30 km/h. Would love to hear your analysis and opinion!
Oh, I like that idea. I have lots of thoughts, and have worked on quite a few traffic calming / speed reduction projects.
Why didn't they make the downtown car-free?
@@kevinlove4356 aye I'd be all for it brother 😃 but we're talking about all of metropolitan Zurich, most of the city. That seems unrealistic.
@@TheShizznac In your original post you wrote "downtown roads." So the model I had in mind was Utrecht, which has an excellent car-free downtown.
Well expressed the facts behind. Nice Video. I liked. Subscribed to your channel.
That was mind-blowing! And with such a simple and graphic explanation! The only thing that was missing IMO, was showing us the car pile-up with >160 cars in the bar diagram, that would have been fun!
Very interesting. It really goes to show how important public transport and bike infrastructure are, when you can just get say 20% of the cars off the road and reduce congestion by half.
What a wonderful explainer and great mathematical analysis - a good example of this is where dolley madison meets lewinsville in tyson’s corner
Good stuff, explaining in intuitive terms how congestion works. Thanks!
Commenting for the algorithms! Great content.
Thanks!
This is excellent stuff, as a current resident of one and former resident of four other top 11 metro areas in the US, the key to all of my public transit willingness is how big the difference in time is between driving and other modes of transportation. Of course there are days I drive instead of bus/train if I had other errands that day, but traffic congestion factors like this one are a huge influencer in commuter decision making. This leads right into your content on bus only lanes and why metros or commuter trains that aren’t at the mercy of freight are critical. The real question is how much time is saved or at least roughly equal to take public transit (or carpooling) versus driving and being stuck in intersections like this one.
All this stuff really is connected!
High quality video, congrats!
Thanks!
Thanks a lot!
That transition at 4:08 is… *chef’s kiss*
Graphics are hard!
@@CityNerd They turned out great!
What an excellent teaching video. Kudos. 👏🏽
5:00 This was a great visualization.
I love how he's totally bored by his own specialization and as this "you know... whatever" kind of tone. That's authenticity. 👍
suggestion: give it a "drop arrow" where they are forced to give way to oncoming traffic in peak times, that will back it up even further, like.. way further then people will need to find alternate routes which in turn reduces the traffic because they are choosing alternate methods.
But alas, the engineers decide to extend the green and add another lane, adding to the overwhelming chaos that ensues, construction recently finished on a right turn where they added a lane (Australia) doubling the capacity inside the lanes, how long do you think it will last before it will become congested again?
Another example is on the same road, they extended the right turn lane about an extra 50 meters (enough to fit 8 wagons) how long do you think that will last?
People used to take alternate routes rather than being stuck in traffic, how long will it be before they are content with being stuck with a lineup that will take 3 cycles to get through when you are at the back of the line?
Sometimes it's best to either have a drop arrow as I stated, or say outright "no right turn between X and Y times of the day."
Really shows how car pooling and taking transit makes a difference. Great video.
I don't get why all these city planners suggest fees though for driving. That's not really fair as it punishes the poor and those who don't live close to where they need to be.
@Zaydan Naufal yeah of course, but that isn't always available. Car pooling isn't great but at least it's one more car off that road.
This was awesome! Thank you!
Could you do a video talking more in depth about health problems related to poor urban planning and potential solutions?
On Memorial Day, thanks to a closed road, from the point i first stopped, it was the fourth light cycle before i completed my left turn in Vienna, VA,
Congestion pricing is super interesting, but it becomes a real problem real quickly if you don't solve the transit problem first.
Part of why the entire concept makes elected officials extremely nervous.
More of this kind of content please. Also, if you could discuss bus bunching in the same manner, that would be great!
Or just disallow left turns (everybody has to turn right 3 times instead). Of course, left hand arrow turns was just an example.
As a former resident of Southwest Florida, I can confidently say that adding additional lanes in order to alleviate congestion is definitely a cheap and reliable way to make sure there are never any delays and that every driver is happy and calm. **twitches**
Ft Myers' transportation system kinda blew me away when I visited a couple years ago. Sanibel and Captiva are pretty cool, though!
@@CityNerd I lived on Sanibel when I was in high school and was able to move back with my family for a few years. Sanibel is really lovely, and they've done a good job of keeping the commercialization to a minimum. I remember the "McStop" campaign of the mid-90s, when McDonald's wanted to build a restaurant on the island and made all these modifications to the plans to adapt it so it would blend in, but the residents kept it from happening. The only chains are Subway and Dairy Queen, and they were there before the city was founded in 1974.
That's why you should plan your route to minimize time consuming left turns during rush hour.
Not to mention that making a left turn puts you at higher risk of getting involved in an accident. There's a reason why UPS instructs drivers to avoid left turns like the plague.
I don't think Amazon has the same protocol as UPS...but I'm not sure. Would be interesting to explore that.
This is fricking fantastic. Go CityNerd go!
Combine the two: congestion pricing to fund public transportation, better sidewalks, and bike lanes. BASED.
based af
Can you do a video comparing Level of Service and Vehicle Miles Traveled? I've heard that they can be used in place of one another when looking at road projects or proposed developments in an area. It seems to me that each metric measures something very different.
They are very different. State of California is the leader, I believe, in moving transportation impact studies from a LOS focus to a VMT focus. I'll add it to my topic list!
I love these policy videos! I'll be back for congestion pricing!
I really liked the explanation. Easy to understand but not going into the mind-numbing math behind the scenes. It’s not rocket science but like you said, it’s not linear either.