The objectives of this laboratory experiment were to investigate how reaction time to centre high-mounted stop lamps (CHMSL) is affected by context (the presence or absence of conventional low-mounted stop lamps), aspect ratio (the ratio of height to width), intensity, and ambient illumination. Recent trends in auto body styling have led to the use of long, narrow CHMSLs. These developments have increased the importance of understanding the efficacy of stop lamps with effective luminous areas that are long and narrow. Participants performed a reaction-time task by responding to the onset of CHMSLs with varying characteristics. The results of this experiment indicate that context, CHMSL aspect ratio and CHMSL intensity significantly affect reaction time. Specifically, participants' reaction times to the onset of simulated CHMSLs mere longest when stimulus intensity was low, aspect ratio was large, and the CHMSL was shown without low-mounted stop lamps. These results, which are similar to those of a previous investigation (Sayer, Flannagan, and Sivak, 1995), suggest that intensity should be emphasized in the design of all stop lamps, and that combinations of large aspect ratio and low intensity should in particular be avoided.
Samenvatting