Question

Traffic counts and signal timing data were collected for the intersection of Sand Creek Road and Wolf Road. The intersection is signalized. The collected data show that, for a particular cycle, vehicles on the through lane of the SB of Sand Creek Road had the following arrival headway pattern (counted from the start of the red time of the cycle):

– 2.5 seconds for the first 10 seconds

– 2 seconds for the time period of 44 ‐ 50 seconds, and for the time period of 130 ‐ 166 seconds

– No vehicle was observed in‐between of the above time periods.

– Collected data also show that the cycle length is 200 seconds with 140 seconds for the effective red time and 60 seconds for the effective green time. Assume the discharge headway after the signal turns green is 2 seconds. Ignore the interactions of vehicles from left‐ and right‐turn lanes when you conduct the analysis.

Find:

– Maximum queue size

– Maximum delay

– Total queuing delay

– Average queuing delay

Answer 1

Arrival and departure rate are found out using the given time interval and headway.

Total vehicle arriving or departing in an interval = (time interval)/headway.

Arrival/departure rate = (Total vehicle arriving/departing)/time interval.

Queuing diagram is drawn.

Important points are determined.

The required parameters are found out.

Solution is uploaded below.

• 
• Maximum que size is along the interval between 140-166 sec,as

So que length at any interval between 140-166 sec is equal and maximum=12 vehicles(solved above)

• Area between curves can be found out by dividing the sections into trapezoids and triangles.