FAST-RISE BRAKE LAMP AS A COLLISION PREVENTION DEVICE
Conventional tungsten-filament brake lamps have a relatively slow rise time. It takes approximately 250 msec for them to reach 90% of the asymptotic luminous intensity. This slowness of response can cause important delays of warning information to following drivers. We have designed a simple and relatively inexpensive circuit that produces a faster warning signal using a conventional lamp. As we have reported previously, this device reduces reaction times to the onset of brake lamps by about 115 msec. The present study evaluated the benefits of a 115 msec reduction in driver brake reaction time. Two approaches were used. In the first approach we calculated the reductions in effective stopping distance assuming a range of initial speeds. The results indicate, for example, that if the initial speed is 100 km/h, the reduction in the effective stopping distance is 3.2 m. In the second approach we calculated the reductions in the proportions of very long reaction times, assuming a normal distribution of reaction times that is shifted by 115 msec. For the distribution without the device we assumed a mean of 1.25 sec and a standard deviation of 0.46 sec. The results indicate, for example, that decreasing the mean by 115 msec yields a 55% reduction in the frequency of reaction times that are longer than 2.5 sec.
University of Michigan Transportation Research Institute2901 Baxter Road
Ann Arbor, MI United States 48109-2150
- Sivak, M
- Flannagan, M J
- Publication Date: 1993-1
- Pagination: 8 p.
- TRT Terms: Brake lamps; Emergency response time; Luminous intensity; Reaction time; Stopping distances
- Subject Areas: Highways; Safety and Human Factors; Vehicles and Equipment; I91: Vehicle Design and Safety;
- Accession Number: 00629026
- Record Type: Publication
- Source Agency: University of Michigan Transportation Research Institute
- Report/Paper Numbers: UMTRI-93-5, HS-041 661
- Files: HSL, TRIS
- Created Date: May 11 1993 12:00AM