Lane Departure Warning and Prevention Systems in the US Vehicle Fleet Influence of Roadway Characteristics on Potential Safety Benefits

Road departure crashes account for one-tenth of all crashes but nearly one-third of all fatal crashes. Lane departure warning (LDW) and lane departure prevention (LDP) active safety systems could mitigate these crashes by warning the driver of a lane departure or automatically navigating the vehicle back into the lane. The objective of this study was to quantify the influence of certain roadway characteristics on the effectiveness of LDW and LDP systems within the U.S. vehicle fleet. This study used 478 real-world drift-out-of-lane road departure crashes and simulated them as if the vehicles had been equipped with LDW or LDP systems. The simulations were then repeated as if (a) all of the roadways had lane markings, (b) the roadway shoulders were expanded, and (c) lane markings were present and the shoulder widths were expanded. With the existing roadway infrastructure, LDW and LDP were found to potentially prevent 28% to 32% of U.S. road departure crashes and 21% to 28% of cases of serious driver injury. When lane markings were added to the roadways, LDW and LDP could prevent 32% to 36% of crashes and 27% to 31% of cases of serious driver injury. When only shoulder widths were expanded, LDW and LDP could prevent 50% to 54% of crashes and 44% to 48% of cases of serious driver injury. When lane markings were present and the shoulders were expanded, LDW and LDP could prevent 72% to 78% of crashes and 60% to 65% of cases of serious driver injury. The findings of this study highlight the important influence of roadway infrastructure on the performance of LDW and LDP.