Drivers’ use of front crash prevention, lane departure warning and prevention, and speed warning systems

October 2024

Introduction: Crash avoidance technologies can aid with driving and reduce crashes, but only if drivers use them. This study measured current use of front crash prevention, lane departure (i.e., lane departure warning or lane departure prevention), and speed warning systems (i.e., systems designed to alert the driver when they are traveling above the speed limit, either visually or both visually and audibly). Methods: We observed activation rates of systems that retain their last setting with each ignition cycle on over 2,000 model year 2017 to 2023 vehicles from six manufacturers serviced at branded dealerships in the Washington, DC, metro area in 2023. We analyzed vehicle and driver demographic characteristics to study factors associated with system use. Results: Automatic emergency braking was enabled on 93% of vehicles, ranging from 86% to 100% by manufacturer. Lane departure warning or prevention systems were activated on 87% of vehicles, ranging from 56% to 99% by manufacturer. The lane departure system activation rates were higher for systems with prevention capabilities than for systems with only warning capabilities. They were also higher for systems activated through a settings menu rather than a button. Visual speed warnings were activated on 70% of vehicles studied, and 14% of vehicles with an audible speed warning had the audible alert turned on. Conclusions: This study provides evidence that driver use of lane departure systems has improved over time, which may be due to more lane departure prevention over lane departure warning systems and system design changes that made them more acceptable. Early use of visual speed warning alerts is strong, and we provide manufacturers and engineers suggestions of ways to improve the acceptability of audible speed warning alerts, which are effective at reducing speeding behavior.