Effectiveness of LED stop lamps for reducing rear-end crashes: analyses of state crash data

  • Published: U.S. Department of Transportation, National Highway Traffic Safety Administration (NHTSA); Report number DOT HS 811 712, 2013
  • Authors: Greenwell N K
  • Date Added: 25 Jan 2014
  • Last Update: 25 Jan 2014
  • Format: pdf

Objectives:

To analyse the crash-reduction benefits of LED (light-emitting diode) stop lamps and LED centre high-mounted stop lamps (CHMSL) using real-world crash data.

Methodology:

NHTSA statistically compared the overall ratio of rear-impact crashes to a control group of frontal impacts before and after the switch to LED.

Key Findings:

  • Overall, the analysis does not support a firm conclusion about whether LED stop lamps and LED CHMSL are more effective than incandescent lamps.

  • The main analysis shows a significant overall 3.6% reduction in rear-impact crashes with LED.

  • On the other hand, a non-parametric analysis not only fails to show improvement in significantly more than half the models, but actually shows an increase in rear impacts with LED for 9 of the 17 make-models that switched to LED.

  • It was just the favourable results for high-sales vehicles such as the Honda Accord that pulled the overall result to a positive benefit.

Keywords:

NHTSA, NCSA, State Data System, effectiveness, evaluation, statistical analysis, automotive lighting, centre high mounted stop lamp, CHMSL, rear impact, crash avoidance, stop lamps

Comments:

None of these 17 make-models is a “clean” switch pair that shifted to LED without changing anything else. All of the switch pairs shifted to LED at the same time that they changed the rear-lighting configuration and/or redesigned the vehicle.

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