In this US study, three experiments were conducted using a driving simulator to determine whether yellow tail lamps would improve the detection of braking signals in complex traffic situations, and to gauge whether different attentional systems are engaged in relation to yellow versus red tail lamps. The 20 participants with a mean age of 18.7 years in this study were required to follow nine vehicles during a 15 minute nighttime drive in heavy highway traffic. Participants were presented with a dual task scenario that involved braking and lane changes, and were randomly assigned to a scenario that used red or yellow tail lamps.
Results showed that the use of color to help drivers differentiate between tail lamps appeared to reduce the visuomotor and cognitive demands on drivers to look for brake lamps. The use of yellow lamps reduced the need to search for brake lamps as the color change pops out visually system, whereas a red lamp could also indicate a turn signal. This makes available more visual attention needed for other driving tasks, and improves the speed and accuracy of brake lamp detection. Pre-attentive, parallel visual processing was shown to be a mechanism that allows better performance. Authors suggested that the use of yellow brake lamps be considered in vehicles to decrease the visual workload for drivers. This consideration should be further tested with simulators and in real world environments.
McIntyre, S., Gugerty, L., & Duchowski, A. (2012). Brake lamp detection in complex and dynamic environments: Recognizing limitations of visual attention and perception. Accident Analysis & Prevention, 45, 588-599.