Abstract:
With the ever-increasing traffic congestion, it is needed to initiate sustainable traffic
management solutions. There is a need to establish signal design standards taking in to
account the latest trends in traffic signal development so that there will be consistency in
traffic signal designs and also to make provision to incorporate future coordination and other
automation such as monitoring violations and gathering traffic flow information for real time
updates. More importantly standardization will minimize user confusion and improve safety
at traffic signals and help improving traffic flow and user satisfaction.
The congestion issues that are related to signalized intersections are not only inherent to a
particular intersection, but rather can be a result of the signal arrangements at nearby
intersections. This research identifies the issues with the typical intersection arrangements,
and aims at developing a guideline to be followed for traffic signal designs especially when
traffic signals are to be coordinated intersection clusters.
The necessity of a properly calibrated software for the local condition has been identified as a
key component in related literature. VISSIM traffic simulation software was calibrated for
the Sri Lankan condition after collecting information from more than 10 intersections in and
around Colombo. From the video surveys and manual observations considered, the traffic
volumes along with the turning movements, vehicle mix and queue lengths were obtained and
compared with the simulated results with an accuracy of ±10.
With the calibrated VISSIM software, the guidelines to be followed were developed
considering the factors such as; identification of the coordinated phase, determination of
individual signal timings for intersections, determination of phase timings for coordinated &
non-coordinated directions and optimizing the offsets.
The developed guidelines were tested for the Baseline Road intersection cluster and
simulation results shows significant delay reductions over xx% for any approach can be
achieved in the coordinated directions without adversely affecting the non-coordinated
directions.
