How Does Lane Departure Warning Effectiveness Vary by Severity of Departure

Abstract

Lane departures are a significant traffic safety problem. They can be attributed to a variety of types of impairment including the increasing prevalence of distracted driving. Research to date has focused on how drivers respond to imminent lane departure warnings, often with short time to line crossing at the onset of the alert. This paper examines how this effectiveness changes over a range of severities associated with various times to line crossing. Although warning systems are generally beneficial in reducing the severity of lane departures, time to line crossing had mixed effects on lane departures. Longer time to line crossing was associated with a greater likelihood of departing the lane but with less severe lane departures. Additionally, an active warning that provides steering torque to help correct lane departures showed decreased effectiveness with increasing time to line crossing in terms of likelihood of lane departure and duration and area of lane departure. These results point to the importance of considering the range of situations in which a warning may be issued, not just the most severe cases.