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Sub-problem 4a - Page 3 of 5

ID# C204A03

Sub-problem 4a - Clifton Country Road AM peak hour - Existing Conditions

Coordination
Since this intersection is part of a network, we must determine whether coordination would be useful for the eastbound approach. The westbound approach has traffic coming from both southbound and northbound off-ramps as well as Route 146, so coordination wouldn’t be as useful there.

Exhibit 2-41 shows that if the eastbound arrival type were to change from 3 (Dataset 32) to 5 (Dataset 34), the average delay would drop from 28.6 to 20.1 seconds per vehicle for the eastbound throughs and from 10.2 to 2.4 seconds per vehicle for the eastbound rights. Those are decreases of 30% and 76% respectively. Similarly, the average queues for the through lanes would drop from 8.3 to 7.5 vehicles and the 95th percentile queue length would drop from 15.6 to 14.2 vehicles. If we assume the coordination is worse than random arrivals, for example, arrival type 1 (Dataset 35), the average delays for the throughs rise from 28.6 to 37.1 seconds per vehicle (for the rights, an increase from 10.2 to 18.0 seconds per vehicle). The queue lengths increase as well.
 

Exhibit 2-41. Clifton Country Road Impacts of Coordination on the Eastbound Approach
Condition* Performance Measure Eastbound Westbound Northbound Southbound OA
L T R Tot L T R Tot L T R Tot L T R Tot
Dataset 32 Base Case Delay 34.5 28.6 10.2 25.6 31.3 21.0 12.9 23.4 33.1 32.0 33.2 33.0 32.3 31.2 32.0 25.9
v/c ratio 0.03 0.81 0.24 - 0.5 0.7 - - 0.41 0.20 0.34 - 0.4 0.2 - -
95-Queue 0.2 15.6 5.3 - 6.9 20.0 - - 4.4 2.2 3.2 - 4.4 2.5 - -
Queue 0.1 8.3 2.6 - 3.5 11.0 - - 2.1 1.1 1.6 - 2.2 1.2 - -
Dataset 34 Arrival Type 5 EB TH&RT Delay 34.5 20.1 2.4 17.2 31.3 21.0 12.9 23.4 33.1 32.0 33.2 33.0 32.3 31.2 32.0 22.6
v/c ratio 0.03 0.81 0.24 - 0.5 0.7 - - 0.41 0.20 0.34 - 0.4 0.2 - -
95-Queue 0.2 14.2 1.7 - 6.9 20.0 - - 4.4 2.2 3.2 - 4.4 2.5 - -
Queue 0.1 7.5 0.8 - 3.5 11.0 - - 2.1 1.1 1.6 - 2.2 1.2 - -
Dataset 35 Arrival Type 1 EB TH&RT Delay 34.5 37.1 18.0 33.9 31.3 21.0 12.9 23.4 33.1 32.0 33.2 33.0 32.3 31.2 32.0 29.1
v/c ratio 0.03 0.81 0.24 - 0.5 0.7 - - 0.41 0.2 0.34 - 0.4 0.2 - -
95-Queue 0.2 16.5 8.1 - 6.9 20.0 - - 4.4 2.2 3.2 - 4.4 2.5 - -
Queue 0.1 8.8 4.1 - 3.5 11.0 - - 2.1 1.1 1.6 - 2.2 1.2 - -
*Using an 82-second cycle length during the a.m. peak hour

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