01631463

Component

This study aims in evaluating the following behavior of vehicles under heterogeneous traffic conditions. For this purpose, access-controlled mid-block segments of multi-lane urban roads of Chennai and Delhi cities are considered. Roadway section of Chennai is six-lane divided, whereas Delhi-Gurgaon road section is eight-lane divided carriageway. Vehicular trajectories are extracted using video files, which captures the traffic movement over certain length across the selected road segments. From the extracted vehicular trajectory data, time-space plots along with relative spacing-speed profiles are developed. Hysteresis phenomenon are identified from relative speed with respect to relative spacing plots of the vehicular pairs. Through the novel application of these hysteresis plots, potential leader-follower pairs are identified. The data pertaining to these vehicular pairs is further used for calibration of Wiedemann car-following models in VISSIM 8.0. Based on a given following vehicle category (for example, motorized two-wheelers), hysteresis plots are segregated based on its combination with different vehicle categories (for example cars, Motorized three-wheelers, etc.) as leading vehicle. Further, calibrated vehicular following model parameters using newly developed methodology, are given as inputs to simulation model. For evaluating the effectiveness of calibrated Wiedemann models, temporal validation is executed using traffic stream characteristics (speed, density and volume) for every 5-minute intervals at macroscopic level. In order to check the influence of calibrated following parameters, simulation models are run with default parameters, it was observed that simulation models with calibrated parameters are giving a better replication of field conditions than models in comparison to default following parameters. The simulation model is then well validated using observed data on derived traffic flow parameters such as speed and density for both the study sections. The validated simulation model is then employed to develop speed-density-flow plots. Using these plots, capacity estimates are derived for varying roadway and traffic conditions, indicting an urgent need to update the existing guidelines given by Indian Roads Congress (IRC). It is also believed that the methodology, to calibrate vehicle category based following parameters, developed in this research work may be useful for Asian countries having non-lane based traffic flow scenarios.

This paper was sponsored by TRB committee ABE90 Standing Committee on Transportation in the Developing Countries.

01618707

17-05479

English

20p

2017

Transportation Research Board 96th Annual Meeting

Digital/other

Figures; References; Tables

Car following; Simulation; Traffic flow; Traffic models; Vehicle trajectories

Chennai (India); Delhi (India)

Highways; Operations and Traffic Management; Planning and Forecasting

Transportation Research Board Annual Meeting 2017 Paper #17-05479

TRIS, TRB, ATRI

Dec 8 2016 12:10PM