To determine the average speed (S), you need to use the speed-flow curves. First, you calculate the free-flow speed, which will allow you to select the appropriate curve (e.g., 55, 60, 65, 70, or 75 mph). Secondly, you will calculate the demand flow rate in pcphpl. You can then draw a vertical line up from this demand flow rate to where it corresponds the appropriate free-flow speed curve. From the point at which they intersect, draw a straight line across to the x-axis to determine the average speed. S and FFS will, of course, be equal to each other in the flat part of the curves (i.e., at low volumes). I hope that helps!
Thank you for posting this! Kudos to you and Iowa State for hiring such concise, clear teachers.
Very nice lecture on Freeway LOS. Concise and clear. Thanks and lot.
That was very useful, thank you
Just a slight notice: FFS is not equal to 65, using SBP-65 equation, S=64.077mi/h which translates to a density of 17.86
Thankyou
Perfect!
Thanks a lot .if possible sir Also upload LOS Analysis of a
Signalized I/S
thanks Sir,
but i have a problem in determinig the average passenger car-speed (S)!
i didn't really get that point
To determine the average speed (S), you need to use the speed-flow curves. First, you calculate the free-flow speed, which will allow you to select the appropriate curve (e.g., 55, 60, 65, 70, or 75 mph). Secondly, you will calculate the demand flow rate in pcphpl. You can then draw a vertical line up from this demand flow rate to where it corresponds the appropriate free-flow speed curve. From the point at which they intersect, draw a straight line across to the x-axis to determine the average speed. S and FFS will, of course, be equal to each other in the flat part of the curves (i.e., at low volumes). I hope that helps!
thanks