Operational Assessment of Joint and Conventional Lane Merge Configurations for Freeway Work Zones

Inefficient traffic operation at work-zone areas typically leads to increased travel time delays, queue length, fuel consumption, number of forced merges, and possibly roadway accidents. Using crash data collected from active work zones in Louisiana between 2003 and 2007, a safety analysis for the conventional lane merge configurations recommended in the Manual on Uniform Traffic Control Devices (MUTCD) revealed that the fatality, injury, and property damage crash rates in the advance warning area of work zones were significantly higher than in other work-zone areas. Intelligent transportation systems offer innovative technological solutions to improve the operational efficiency and safety of work zones through advanced lane merge control strategies that extend beyond the conventional lane merge configuration. This study focuses on the operational efficiency of a newly proposed work-zone configuration, referred to as joint lane merge (JLM), and compares its performance with the conventional lane merge (CLM) configuration. A simulation model (VISSIM) was calibrated with real-world data from an existing work zone on I-55 and used to simulate a work-zone area with both configurations. In total, 25 different scenarios were generated from five different levels of demand and five truck percentages. Performance measures in terms of total throughput and average delay time were compared and statistical analysis was conducted to determine whether the differences in operational performance between both configurations were significant. The results showed that the joint lane merge outperformed the conventional lane merge in terms of maximum throughput and average delay per vehicle for all simulation scenarios considered.