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Subproblem 5c - Page 3 of 6 |
ID# C305C03 |
Sub-problem 5c:
Pre-timed vs. Traffic-Actuated Operation
Step 2: Results
Three cases involving
different timing plans will be examined in this sub-problem: The first will
use the optimal timings from Sub-problem 5b. The difference in the results
will be due solely to differences in the HCM treatment of traffic-actuated
control. The results are summarized in Exhibit 3-40.
Note that there
were no differences in the v/c ratio, g/c ratio, or uniform delay values in
the comparison of pre-timed and traffic-actuated operation. The k values
were all 0.5 for pre-timed control and 0.37 for traffic-actuated control.
The reduction in the k values produced a slight decrease in the incremental
delay for all movements, and this decrease was reflected in the control
delay. The overall intersection delay decreased by 1.5 seconds per vehicle, or about 6
percent.
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Exhibit 3-40. Comparison of
Pre-timed and Traffic-actuated Control with the Same Timing Plan |
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|
Pre-timed
Sub-problem 5b |
Actuated
Sub-problem 5c |
|
Eastbound Through |
|
|
|
v/c |
0.83 |
0.83 |
|
g/c |
0.68 |
0.68 |
|
Uniform delay |
14.1 |
14.1 |
|
k value |
0.5 |
0.37 |
|
Incremental delay |
3.6 |
2.7 |
|
Control delay |
17.6 |
16.7 |
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Westbound Left |
|
|
|
v/c |
0.84 |
0.84 |
|
g/c |
0.08 |
0.08 |
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Uniform delay |
54.4 |
54.4 |
|
k value |
0.5 |
.37 |
|
Incremental delay |
41.7 |
33.6 |
|
Control delay |
96.1 |
88.0 |
|
Northbound
Through |
|
|
|
v/c |
0.83 |
0.83 |
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g/c |
0.09 |
0.09 |
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Uniform delay |
53.9 |
53.9 |
|
k value |
0.5 |
0.37 |
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Incremental delay |
21.9 |
16.9 |
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Control delay |
75.8 |
70.8 |
|
Overall
intersection delay |
24.5 |
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