Kawasaki City, Japan has applied a traffic flow simulation model to obtain an improvement in wide area traffic flows. The simulator was established to obtain an estimated figure of CO2 emissions generated by travelling vehicles and to consider the state of each vehicle. An analysis of relations between CO2 emissions, delay time and the number of stops at intersections was performed with the simulator, which resulted in a proposal for a new traffic signal control method to reduce CO2 emissions. The simulation resulted in a reduction of these emissions of roughly 7 per cent from the levels of the exhaust gas produced by the current traffic signal control method.

Case study courtesy of the UNEP Publication, Reducing Emissions from Private Cars: Incentive measures for behavioural change.