Transportation Lab Final
Saturation Flow Rate:
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Average headway (AH)
o AH = (Tn-T4) / (N-4)
o T4 = time the rear axle of the 4th
vehicle enters the intersection
o N = total # of veh. entering the
intersection for the cycle
o Tn = the total time for N veh. to enter
the intersection
Average saturation flow rate (s)
o s = 3600/AH
Startup delay (SD)
o SD = T4 - 4*AH
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Maximum green-time
o Largest green time found
Effective green-time
o = max. green-time - SD + Clearance
time used
o Clearance time normally 0
Cycle Length
o Lab was set to 90 sec cycles
o If not consistent, use the max.
Lane Capacity
o (Effective green / Cycle length) x s
Poisson:
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Conduct Chi-square test
*Complete Stop (S), Rolling Stop (R), No Stop (N), and Stopped by Traffic (T)