Effect of speed humps on instantaneous traffic emissions in a microscopic model with limited deceleration capacity

Abstract

As a common transportation facility, speed humps can control the speed of vehicles on special road sections to reduce traffic risks. At the same time, it also brings instantaneous traffic emissions. Based on the classic instantaneous traffic emission model and the limited deceleration capacity microscopic traffic flow model with slow-to-start rules, this paper has investigated the impact of speed humps on the traffic flow and the instantaneous emissions of vehicle pollutants in a single lane situation. The numerical simulation results have shown that speed humps have significant effects on traffic flow and traffic emissions. In free flow region, the increase of speed humps leads to the continuous rise of CO 2, NO X and PM emissions. Within some density range, ones find that these pollutant emissions can evolve into some higher values under some random seeds. Under other random seeds, they can evolve into some lower values. In the wide moving jam region, the emission values of these pollutants appear sometimes continuous or intermittent phenomenon. Compared to the refined NaSch model, the present model has lower instantaneous emissions such as CO 2, NO X and PM and higher VOC emissions. Compared to the limited deceleration capacity model without slow-to-start rules, the present model has also lower instantaneous emissions such as CO 2, NO X and PM and higher VOC emissions in the wide moving jam region. These results can be also confirmed or explained by the statistical values of vehicle velocity and acceleration.