Inefficient operation of traffic in work zone areas not only leads to an increase in travel time delays, queue length, and fuel consumption but also increases the number of forced merges and roadway accidents. This study evaluated the safety performance of work zones with a conventional lane merge (CLM) configuration in Louisiana. Analysis of variance (ANOVA) was used to compare the crash rates for accidents involving fatalities, injuries, and property damage only (PDO) in each of the following 4 areas: (1) advance warning area, (2) transition area, (3) work area, and (4) termination area. The analysis showed that the advance warning area had higher fatality, injury, and PDO crash rates when compared to the transition area, work area, and termination area. This finding confirmed the need to make improvements in the advance warning area where merging maneuvers take place. Therefore, a new lane merge configuration, called joint lane merge (JLM), was proposed and its safety performance was examined and compared to the conventional lane merge configuration using a microscopic simulation model (VISSIM), which was calibrated with real-world data from an existing work zone on I-55 and used to simulate a total of 25 different scenarios with different levels of demand and traffic composition. Safety performance was evaluated using 2 surrogate measures: uncomfortable decelerations and speed variance. Statistical analysis was conducted to determine whether the differences in safety performance between both configurations were significant. The safety analysis indicated that JLM outperformed CLM in most cases with low to moderate flow rates and that the percentage of trucks did not have a significant impact on the safety performance of either configuration. Though the safety analysis did not clearly indicate which lane merge configuration is safer for the overall work zone area, it was able to identify the possibly associated safety changes within the work zone area under different traffic conditions.

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 datafrom 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.

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