I actually was visiting Utah and drove through one and didn't even realize I was on the wrong side of the road until I went back the next day and was like what the heck haha
Yeah, I suppose it's great for moving cars and trucks, but it's not so great for pedestrians and cyclists, and it certainly doesn't make the area more pleasant for anyone who might live nearby. The street that crosses the interstate becomes more a part of the interstate than a part of the surrounding street network.
two traffic circles would do the same, minus costs of a traffic lights and would set a drive slower point after leaving highway, but yes invent the wheel new again....
So what happens if the traffic lights at the crossings go out? We all know how to get through a normal right-angles intersection when the lights aren't working. I don't know what people would do for these.
+Bob Munck The two lights ARE simple right angles, with all traffic in each roadway only going in on direction. Much simpler than a non-functioning signal at a conventional intersection, with cars coming from four directions all facing three choices (left, straight, right).
+Scott B Thanks for the response, but I think you're wrong about the right angles. I used the Google Maps satellite view to measure the angles of two DDIs that I know about, one on Rt. 15 south of us where it crosses I-64 west of Richmond VA and one north of Charlotte NC where Catawba crosses I-77 (coincidentally near the new house we're building). All four intersections meet at close to 135°. Your second point is a good one, but I still don't know how you'd get the two oncoming lanes to alternate crossing the intersection. You're going to have cars from each lane starting to cross simultaneously, and immediately colliding. FYI, we currently live 4 miles north of where Rt 15 crosses I-66 in Haymarket VA, an intersection that is being converted to DDI.
What an absolutely dystopian hellscape. Imagine trying to simply exist as a pedestrian or cyclist in this. A fine example of how cynically human-last American infrastructure design is.
At 4:15 the driver of the white truck does not keep his vehicle within the lane despite the carefully-painted lines. Sloppy driving in a DDI makes it that much more confusing to drivers. Also, drivers will carelessly turn right or left into oncoming traffic at several points in a DDI regardless of how complete the signage. Wrong-way crashes are the deadliest type and the DDI offers several opportunities for careless drivers to cause them.
Got any statistics on wrong way crashes inside a DDI vs a conventional diamond interchange? You'd think going up a ramp the wrong way would be almost impossible with DDI whereas it's VERY easy and common with a conventional diamond for drunk drivers to turn right onto an exit ramp.
Michael Manola and most likely the only reason why many agencies, let alone MoDot, decided to build/keep building these DDI's is because they DON'T even have to replace/widen the existing bridge; not only saving TONS of $$$, but also reducing the amount of time building it!
Those tiny strips of concrete don't accommodate bikers of pedestrians. There should at least be some barrier between pedestrians and fast moving cars. Its obvious it isn't working when you see nobody risking there life to cross.
Doesn't look pleasant or convenient for people on foot. Long circuitous routes with multiple crossings of wide roadways do not appear to be safe or convenient for pedestrians or bicyclists. Were any peds or cyclists interviewed for for the after evaluation? It appears these are intended for use only in areas where peds and cyclists are non-existent or are encouraged to be rare.
I actually was visiting Utah and drove through one and didn't even realize I was on the wrong side of the road until I went back the next day and was like what the heck haha
LOL
In practice, it seems that if the traffic exceeds road capacity it's more susceptible to gridlock than the conventional intersections it replaced.
It's so intuitive it only took 7 minutes to explain it.
I love DdIs
Me too, btw it's DDI, u put Ddi, witch isn't that bad, I'm just sayin
:)
Yeah, I suppose it's great for moving cars and trucks, but it's not so great for pedestrians and cyclists, and it certainly doesn't make the area more pleasant for anyone who might live nearby. The street that crosses the interstate becomes more a part of the interstate than a part of the surrounding street network.
two traffic circles would do the same, minus costs of a traffic lights and would set a drive slower point after leaving highway, but yes invent the wheel new again....
the only drawback of that type of interchange is the traffic light, right?
No, it's a type of road-hwy/interstate or a hwy-interstate type of interchange, so no
U can also use yelds too...just syin
So what happens if the traffic lights at the crossings go out? We all know how to get through a normal right-angles intersection when the lights aren't working. I don't know what people would do for these.
+Bob Munck The two lights ARE simple right angles, with all traffic in each roadway only going in on direction. Much simpler than a non-functioning signal at a conventional intersection, with cars coming from four directions all facing three choices (left, straight, right).
+Scott B Thanks for the response, but I think you're wrong about the right angles. I used the Google Maps satellite view to measure the angles of two DDIs that I know about, one on Rt. 15 south of us where it crosses I-64 west of Richmond VA and one north of Charlotte NC where Catawba crosses I-77 (coincidentally near the new house we're building). All four intersections meet at close to 135°. Your second point is a good one, but I still don't know how you'd get the two oncoming lanes to alternate crossing the intersection. You're going to have cars from each lane starting to cross simultaneously, and immediately colliding.
FYI, we currently live 4 miles north of where Rt 15 crosses I-66 in Haymarket VA, an intersection that is being converted to DDI.
U should probably act like it's a roundabout, yeld to the inside of the interchange, I geuss
@@BobMunck wat?
What an absolutely dystopian hellscape. Imagine trying to simply exist as a pedestrian or cyclist in this. A fine example of how cynically human-last American infrastructure design is.
At 4:15 the driver of the white truck does not keep his vehicle within the lane despite the carefully-painted lines. Sloppy driving in a DDI makes it that much more confusing to drivers. Also, drivers will carelessly turn right or left into oncoming traffic at several points in a DDI regardless of how complete the signage. Wrong-way crashes are the deadliest type and the DDI offers several opportunities for careless drivers to cause them.
Got any statistics on wrong way crashes inside a DDI vs a conventional diamond interchange? You'd think going up a ramp the wrong way would be almost impossible with DDI whereas it's VERY easy and common with a conventional diamond for drunk drivers to turn right onto an exit ramp.
What about raising one level of only one side of the "diamond" thing. There will be no more need for red light. As simple as that
How about if one direction was elevated, you wouldn't need signalization....
Money. Bridges cost millions and millions.
Michael Manola and most likely the only reason why many agencies, let alone MoDot, decided to build/keep building these DDI's is because they DON'T even have to replace/widen the existing bridge; not only saving TONS of $$$, but also reducing the amount of time building it!
Those tiny strips of concrete don't accommodate bikers of pedestrians. There should at least be some barrier between pedestrians and fast moving cars. Its obvious it isn't working when you see nobody risking there life to cross.
Doesn't look pleasant or convenient for people on foot. Long circuitous routes with multiple crossings of wide roadways do not appear to be safe or convenient for pedestrians or bicyclists. Were any peds or cyclists interviewed for for the after evaluation? It appears these are intended for use only in areas where peds and cyclists are non-existent or are encouraged to be rare.
Pedestrian crossings are much shorter with a DDI than with a traditional interchange
*facepalm*🤦♂️🤦♀️ *facepalm*
A tiny strip of concrete next to fast moving cars isn't safe at all
SPUI is better and more intuitive.