Abstract:
Traffic congestion has resulted in significant
losses to the economies worldwide with the valuable time lost on
the roads. Nevertheless, significant capacity improvements at
the intersections can be obtained through the implementation of
proper traffic management initiatives. In terms of traffic signal
designs, considerable delay reductions can be obtained through
optimum signal phasing arrangement. The research aims to
develop a set of guidelines to be followed in phase sequencing in
traffic signal designs, when no separate right turn lane is
available. Grounding the theoretical aspects of traffic signal
design, the research considers the effects of different phasing
arrangements for right turns such as total through plus right
turn phase, leading green for right turns only phase and lagging
green for right turns only phase, when no separate right turn
lane is available at a signalized intersection. Using Webster’s
theoretical framework for traffic signals and delay estimations,
the cycle time reductions and the respective delay reductions
were obtained. A traffic micro simulation was also conducted
using VISSIM micro simulation software for further analysis
and verification purposes. It was observed that leading green for
right turns only phase would work only when the right turn
percentage is less than 15%. Considerable delay reductions can
also be obtained through proper selection of phasing
arrangements, depending on varying traffic volumes and right
turn percentages.
