Assessing spatial and temporal effects due to a crash on a freeway through traffic simulation

• The focus of this paper is to simulate, evaluate and assess spatial and temporal effects in travel time variation and upstream distance or length of upstream links affected due to a crash.
• Fatal crash on freeways has an effect under low, moderate, and high traffic volume conditions, whereas injury crash has an effect only under moderate and high traffic volume conditions.
• The travel time variation and upstream distance affected due to a fatal crash on the right-most lane was generally higher than fatal crash on the left-most lane.
• The upstream distance affected due to a fatal crash varied from 1.5 miles to ∼7.5 miles based on traffic volume and lane on which the fatal crash occurred. It varied from ∼0.5 miles to 7 miles due to an injury crash and traffic condition.
• Queue may start dissipating at least 15 min after blocked lanes are re-opened for normal traffic flow depending on the type of crash, traffic volume and lane in which the crash occurred.

The focus of this paper is to simulate, evaluate and assess spatial and temporal effects in travel time variation and upstream distance or length of upstream links affected due to a crash. Traffic simulations were conducted for different conditions in VISSIM 5.30™ to obtain travel times at various points upstream of the crash location, over time, along a freeway corridor. Travel time variation between fatal crash condition and no crash condition (baseline condition) and between injury crash condition and no crash condition (baseline condition) were computed and compared to evaluate the effect of a crash on a freeway. Results obtained showed that fatal crash on freeways has an effect under low, moderate, and high traffic volume conditions, whereas injury crash has an effect only under moderate and high traffic volume conditions. The travel time variation and upstream distance affected due to a fatal crash on the right-most lane was generally higher than fatal crash on the left-most lane. The trends remained fairly consistent irrespective of the lane on which an injury crash occurred. The upstream distance affected due to a fatal crash varied from 1.5 miles to ∼7.5 miles based on traffic volume and lane on which the fatal crash occurred. It varied from ∼0.5 miles to 7 miles due to an injury crash and traffic condition. Queue may start dissipating at least 15 min after blocked lanes are re-opened for normal traffic flow depending on the type of crash, traffic volume and lane in which the crash occurred. The results and findings from this research can be applied to emulate dynamic message signs over time and space so as to alert the motorists about the length and duration of congestion depending on the severity of crash and lane on which the crash occurred.