SCOOT is the world leading, traffic responsive Urban Traffic Control system developed in the UK. From release 2.4 it has included a traffic restraint tool known as "Gating". To use the facility, the traffic engineer specifies one or more "bottleneck links" where traffic should be limited, and corresponding gated links where the restrained traffic will be held. A Gating saturation is specified for each bottleneck link. When the saturation on that link exceeds the Gating value, the green time on the gated links associated with that bottleneck is reduced to restrain traffic. TRL now has considerable experience of the practical application of Gating. The Bitterne Road bus priority scheme in Southampton has been converted to operate under SCOOT Gating. In this scheme access to the main road for non-bus traffic is restricted to maintain free-flow conditions on the main road and particularly over a narrow railway bridge at the city end of the scheme. The customised software, fixed-time plans and detectors have been replaced by a standard SCOOT system. Similar systems can now be implemented without the cost of developing special software and signal plans. The traffic engineer simply sets and tunes standard SCOOT parameters to achieve his or her objectives. (A)
Abstract