Micro-Level Analysis on Traffic Flow Parameters at Work-Zone Road Section Using Vehicular Trajectory Data

The research work is carried out to examine microscopic and macroscopic traffic parameters at work zone on high speed urban roads. Due to construction of elevated metro rail project over the study section, having five-lanes in one direction, two-lanes are reduced (since past six months). The traffic data are collected using videography, later, trajectory data is extracted using semi-automated image processing software, under different flow conditions, for with and without work zone scenarios. Time-space plot for with and without work zone scenarios clearly indicates substantial decrement in slope due to construction work zone. Longitudinal speeds of the vehicles under work zone scenarios is decreased significantly, compared to without work zone scenarios. Further, lane utilization behavior under different flow conditions also shows vehicles movement closer to work zone side lane is highly affected under low flow conditions. Hysteresis plot of leader-follower vehicles also shows the increased cautiousness of the drivers at work zone location, as they maintain consistent relative velocity with respect to its leader to avoid rear-end crashes. The concept of perceiving time for driver is proposed in the present study with its basis from hysteresis plot which furthers assessment of chances rear-end crashes. It is found that bikes (motorized two-wheeler) are most vulnerable to rear-end crashes at work zone scenario. Finally, speed-flow relationship developed using Van Aerde model for two scenarios, shows reduction in capacity by about 43%, due to lane drops. It is expected that, outcome of the present study may be useful in exploring traffic operations at the location of work zone, more precisely.