More than half of the UK's 9000-plus signalised junctions are controlled by independently-operated (uncoordinated) signals with green times varying in response to local traffic flows. MOVA (Microprocessor Optimised Vehicle Actuation) is the new signal control strategy researched and developed by TRRL for such isolated intersections. Data from vehicle detectors on the junction approaches are analysed by an on-line microprocessor implementing the MOVA program; the durations of the green signals are controlled by a delay-and-stops minimising logic, or, if any approaches become oversaturated (congested), by a capacity-maximising process. Subject to a final large-scale trial, MOVA is intended as a general replacement for the gap-seeking, D-system vehicle-actuated (VA) control currently in use. This report describes the MOVA system, its main principles, the development trials which have taken place, and the assessments of benefits due to MOVA. It is concluded that MOVA reduces vehicle delay by an average of about 13 per cent throughout the working day, compared with up-to-date D-system VA; further benefits are likely where, as is often the case, critical VA controller settings (maximum green times) are based on out-of-date traffic data. (A)

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