The Effect of Speed Limits and Traffic Signal Control on Emissions

Traffic signals strongly influence traffic in cities – in terms of delay but also in terms of the emissions emitted by traffic. This work analyzes the effect of different traffic control strategies on emissions like NOx and PMx. Simulations of an inner-city arterial show that reducing the speed limit leads to a lower production of NOx and PMx, but to an increase in delay. The impact of the traffic signal control on the emissions is less distinct: A carefully designed co-ordination reduces emissions, while a simple actuated control cannot improve traffic flow and therefore increases pollutant production.