CE571 Traffic Flow Theory - Fall 2006

1-Two vehicles were traveling at 45 mph with distance headway of 150 ft. The leading vehicle slowed down with deceleration rate of 8 ft/sec² for a period of 6 seconds, maintained its speed for 4 seconds, then accelerated with a rate of 6 ft/sec² for 8 seconds. Plot the time/headway diagram throughout the entire time period. Use GM-3 Care following model (a_o = 30 ft/sec and Dt=1 seconds)

 2-A platoon of 4 vehicles was traveling at 45mph with distance headway of 120 feet. The leading vehicle had to decelerate with a rate of 6 ft/sec² for 6 seconds, maintained its speed for 4 seconds, accelerated with a rate of 4 ft/sec² for 5 seconds, and then maintained its speed till the end of the analysis period (20 seconds). Using the GM-3 Model, plot the time/headway diagrams using the following parameters: 

3- Resolve Problem 2 changing the drivers’ Reaction Time (Dt ) to 0.7 second, 1.0 second, and 1.2 seconds. Comment on the results.

 4- Resolve Problem 2 changing the drivers’ Sensitivity Parameter (a_o) to 25 ft/sec, 35 ft/sec and 40 ft/sec. Comment on the results

 5- Using the output from 2 to 4, determine the upper and lower boundaries for the traffic stability Parameter (C =a_o Dt) for a steady state traffic operations.