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This study aims to examine the effects of moving work-zone speed, working lane position, and traffic condition on the travel delay, crash risk, and mortality risk at moving work zones by using microscopic traffic simulation approaches. Two surrogate safety measures including TTC (Time to Collision) and Delta-V are employed to represent the vehicle crash risk and mortality risk, respectively. The simulation experiment is conducted based on the observation data from the road network located in the Haidian District of Beijing. Simulation results show that the moving work-zone speed exhibits higher effects on the travel delay, vehicle crash risk, and mortality risk under the smooth traffic state, as compared with those under the congested traffic state. Greater travel delay and higher crash risk are closely associated with the lanes where there are a larger proportion of vehicles whereas the highest mortality risk is for vehicles traveling in the fast lane. The simulation results also show that the vehicles near the moving work zone are associated with high vehicle crash risk, whereas an increased crash risk is also found for the vehicles far from the moving work zone. [ABSTRACT FROM AUTHOR]

Objective This paper aims to assess the potential crash risks across different traffic lanes (shoulder lane, median lane, and middle lane) near to ramps (before on-ramps, between ramps, and after off-ramps). Methods Field data are collected at seven locations (90 min for each location) during peak hours. Two risk indices based on time to collision, individual risk and societal risk are proposed to represent the distinct interpretations of risks to transport agencies and individual motorists. One-way ANOVA is applied to analyze the risk impact of ramps in various types of locations across distinct traffic lanes. Results Median lanes and sections after off-ramps have relatively lower risks compared to other lanes and sections. The individual and societal risks might not always be consistent since the two risk indices are proposed based on distinct perspectives: transport agencies focus on the crash/conflict frequencies in a road section and individual motorists concern more about the probability of being involved in a crash/conflict during their journey. Conclusions The differences in risks mainly result from the frequent lane-changing and merging activities. This model could be used to evaluate the performance of expressway ramp design. [ABSTRACT FROM AUTHOR]