Estimating Benefits of LDW Systems Applied to Cross-Centerline Crashes

Opposite-direction crashes can be extremely severe because opposing vehicles often have high relative speeds. The most common opposite direction crash scenario occurs when a driver departs their lane driving over the centerline and impacts a vehicle traveling in the opposite direction. This cross-centerline crash mode accounts for only 4% of all non-junction non-interchange crashes but 25% of serious injury crashes of the same type. One potential solution to this problem is the Lane Departure Warning (LDW) system which can monitor the position of the vehicle and provide a warning to the driver if they detect the vehicle is moving out of the lane. The objective of this study was to determine the potential benefits of deploying LDW systems fleet-wide for avoidance of cross-centerline crashes.

In order to estimate the potential benefits of LDW for reduction of cross-centerline crashes, a comprehensive crash simulation model was developed. The basis for the model were the records of 42 crashes extracted from the National Motor Vehicles Crash Causation Survey (NMVCCS) database corresponding to 19,467 crashes nationwide. Each crash was simulated in two conditions: (1) as it occurred and (2) as if the encroaching vehicle had an LDW system equipped. By comparing the simulated vehicle trajectory before and after LDW, the reduction in the probability of a crash was determined. The probability of a crash was summed over all simulations to determine the benefits of an LDW system in preventing cross-centerline crashes. To determine potential bounds on LDW system effectiveness, additional simulations were run taking into account the driver capability to react to a LDW system.

LDW systems could potentially prevent between 29-38% of cross-centerline crashes where the vehicle is tracking prior to the crash. An estimated 11-16% of crashes would have a modified impact location possibly resulting in different occupant injuries. The results show that if LDW systems were applied fleet wide, cross-centerline crashes could be significantly mitigated.