Vehicle Signal Systems: Leveraging Light Source Technologies to Optimize Visual Response

Vehicle signal lighting communicates the presence of a vehicle and critical information about a vehicle’s status, driver intentions, traveling direction to other drivers. Signal systems use color-, intensity- location- and temporal-coding to convey that information. Increasingly, such systems are using new light source and other technologies to encode more complex information. Whereas information about a vehicle’s presence, its braking status and its intention to turn or change lanes might have been conveyed through the same filtered incandescent lamp, vehicle signal systems are increasingly compartmentalized, using arrays of light emitting diodes (LEDs) or other devices to convey the same information. Proposals for dynamic signal lighting systems to communicate factors such as urgency of a very rapidly decelerating vehicle, or proximity to other vehicles, motorcyclists or bicyclists, or the safe following distance for a given combination of light and weather conditions. In this paper, the intensity, color, spatial and temporal characteristics of light sources supporting driver perception and recognition are summarized. It is argued that the technological characteristics of new light source technologies offer potential benefits in terms of meeting the visual and perceptual needs of drivers from signaling systems.