Safety Assessment of Different In-Vehicle Interface Designs for Bus Collision Warning Systems

Document Type

Journal Article

Publication Date


Subject Area

infrastructure - vehicle, planning - safety/accidents, ridership - drivers, mode - bus


Transit buses, Road safety, Reaction time, In-vehicle displays, Highway safety, Ergonomics, Driving simulators, Driver vehicle interfaces, Collision avoidance systems, Bus operators, Bus driving, Bus drivers, Automobile driving simulators


Numerous studies have concluded that collision warning systems (CWSs) help drivers be aware of imminent dangerous situations. Driving safety and ergonomics make designing a CWS a very important task. Many studies have explored the effects of different types of CWS interface designs on driving safety performance. However, most of these studies were for passenger cars, with few studies focusing on buses. This study investigates the effects of four different types of in-vehicle bus CWS interfaces on driver reaction time to front events (i.e., a lead vehicle breaking suddenly) and side events (i.e., a vehicle cutting in too close) using a bus driving simulator. Twenty-nine professional bus drivers participated in the experiment. For both front events and side events, the driving experiment results reveal that driver reaction times are highly correlated with crash occurrence. The four different types of bus CWS interface designs can significantly reduce driver reaction time. Driver response time is the shortest for the interface using a beep and symbol shown on a heads-up display indicating the direction of danger. This study concludes that buses should be equipped with CWSs to protect the safety of bus drivers and passengers.