Investigation of Traffic Management Schemes

The poster presents the combination of a traffic model known as Paramics and an emissions model known as VERSIT+ to investigate the effects of possible traffic management schemes on emissions. The combination of these models shall aid in developing traffic management systems and urban planning.

Paramics: The Micro-simulation Traffic Model

Using Paramics, a micro-simulation network was constructed for the area of Nieuw Zurenborg, part of the 19th century city belt of Antwerp, Belgium. The traffic counts supplied by the Flemish Department of Mobility and Public Works, were used to calibrate the traffic flows during morning rush hour. The model generates the position, speed and acceleration of each vehicle on the network.

Discussion

Paramics and VERSIT+ were jointly used to examine two traffic management schemes in Nieuw Zurenborg, part of the 19th century city belt of Antwerp, Belgium. When the speed-limits for all the roads in this network were reduced, the emissions were reduced especially on the freeway. CO2 reduction is due to higher fuel efficiency at speeds around 70 km/h compared to 100 km/h. Emissions of NOx and PM10 decrease with speed in the higher speed range but remain fairly constant at moderate speeds. Secondly, the effect of a green-wave (synchronization of traffic signal lights) along a major road in this network was investigated. The results showed that the presence of green-wave reduces the emissions by about 10%. Transient engine operation results in higher emissions.

Micro-Simulation of a Traffic Fleet to Predict the Impact of Traffic Management on Exhaust Emissions.

M. Madireddy1*, B. De Coensel2, I. De Vlieger1, D. Botteldooren2, B. Beusen1, B. Degraeuwe1, G. Lenaers1 , A, Can2, A. Eijk3

1Flemish Institute of Technological Research (VITO), Mol, Belgium, 2 Ghent University, Gent, Belgium 3TNO, Delft, Netherlands

VERSIT+: The Emissions Prediction Model

VERSIT+ consists of a set of statistical functions for detailed vehicle categories that have been constructed using multiple linear regression analysis. The model is based on a very large database (12000 tests on 153 speed profiles) with data for every vehicle class categorized by vehicle size and fuel. The inputs for the model are vehicle category, vehicle positions and speed for all vehicles in the network, which are obtained from a traffic model like Paramics. VERSIT+ generates spatial and temporal emissions for each vehicle class which represents an average or a typical vehicle. The model is validated by using the data obtained from VITO’s on-board measurement system and on an average, the model predicted the location of instantaneous peaks and aggregated emissions very well. The instantaneous predictions were also acceptable.

Scheme-1: Effect of reduced road speed limit

To understand the effect of traffic speed limit on emissions, two scenarios are created using the Paramics network file. The network in Nieuw Zurenborg is analyzed with original traffic at regular speed limits and a new scenario is created in the same network with the speed limit on the freeway reduced from 100 km/h to 70 km/h, on the major roads from 70 to 50 km/h and on minor roads from 50 to 30 km/h. The corresponding emissions in both the scenarios are compared. The speed limit reduction has caused a reduction in the emissions of both cars and heavy duty vehicles (see table). The most important effect is found on the freeway (map) for all pollutants.

Scheme-2: Effect of green-wave on emissions

To appreciate the significance of synchronization of traffic lights along a road, the following scenarios are examined on the N184 road or Plantijn & Moretuslei. The original scenario is the one with the green-wave, where all the traffic signals are co-ordinated. A second scenario is created by removing the synchronization or ‘killing’ the green-wave. It can be noted from the figure below that when the green wave is killed, it has adversely affected the emissions around the intersections where vehicles accelerate. The aggregate increase of emissions along the road is about 10 %.

N184