Comparative study of theoretical, simulation, and field platoon data

Abstract

Platoon dispersion along arterial links constitutes an important factor in determining whether adjacent traffic signals should be co-ordinated. The amount of dispersion also determines, to a great extent, the number of vehicular stops and total delay in the co-ordinated movements. The purpose of this study was first to evaluate the impact of distance on the dispersion of platoons discharged from intersections using data collected in the field and second to determine if similar conditions could be modelled with reasonable accuracy using the theoretical or simulation models. To evaluate the impact of distance on platoon dispersion, the proportion of platoons arriving during a series of time intervals was tabulated and plotted. These plots were used to determine the maximum percentage of the platoon that can pass through a particular green window downstream given a perfect offset. Field platoon data was compared to both Robertson's model, which is used in TRANSYT signal design software, and CORSIM simulation model. Our research found that CORSIM was more conservative in quantifying the benefit of traffic signal co-ordination for small green windows, where Robertson's model was observed to be more conservative in quantifying the benefit for large green windows as the dispersion parameter increases. (A)