Effects of Traffic Signal Coordination on Traffic- and Emission-Related Evaluation Parameters

A good coordination of traffic signals can reduce waiting times, the number of stops and accelerations, and thus increase travel speeds, which can lead to a reduction in fuel consumption and air pollutant emissions. To investigate the effects of traffic signal coordination on traffic and emission parameters, simulation studies are advantageous over time-consuming field tests to quantify and evaluate quickly, safely and cost-effectively a large number of different input variables, such as intersection distances, traffic volumes and different signal control configurations. This paper describes the findings of an extensive simulation study in which a microscopic traffic flow simulation model was coupled with an emission model. Through the simulation of a range of scenarios, the model is used to investigate the influence of inter alia traffic volume, signal coordination schemes and signal parameters on carbon dioxide, nitrogen oxides and particulate matter emissions along an arterial road equipped with a series of traffic lights. Results showed that shorter distances between the signalized intersections led to about 20% higher emission values. Furthermore, different cycle times and their effects on emissions were investigated, whereby higher cycle times led to lower values of about 14% less emissions.