Lesson
Test new signal timing plans, even on a shoestring budget.
Experience from a synthesis of signal timing projects.
July 2005
United States
Background (Show)
Lesson Learned
The signal timing development process involves eight key steps, ranging from the organization of existing data, to the collection of new data and the calculation of local timing and coordination parameters. The final step in the process is the installation and evaluation of the new signal timing plan. It is important to test the effectiveness of the new settings, so that any necessary adjustments can be made to maximize operational efficiency.
The following specific lessons learned are made with regard to evaluation of signal timing plans on a shoestring budget:
- Conduct travel time and stopped-time delay studies, when the budget allows. The travel time studies of a route up and down the arterial will provide a quantifiable measure of the traffic performance in the corridor. To complement this information, delay studies at selected intersections will provide insight to the operation of specific intersections. It is recommended that delay studies be conducted at the critical intersection in the grouping. The critical intersection is generally the one that is most congested and that drives the cycle length for the group. The combination of travel time studies and delay studies will provide an excellent baseline condition against which future changes in signal timing can be compared.
The following specific lessons learned are made with regard to evaluation of signal timing plans on a shoestring budget:
- Install the signal timing parameters in each controller.
- Test the plan during a benign traffic period, such as mid-morning after the morning peak rush hour. This will enable the agency to observe that the offsets are as expected and to identify any serious discrepancies without having a large negative impact on traffic operations.
- Place the plan in operation during the period for which it was developed. Once the plan has been tested during a period of low traffic demand, then it can be used during the period for which it was designed. Again, the offsets at each intersection should be observed. During peak periods, left turn bays should be checked for spillback.
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Systems Engineering
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System Verification & Deployment
System Validation
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Lesson ID: 2007-00388
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