DOT HS 808 696      March 1998
NHTSA Technical Report

The Long-Term Effectiveness of Center High Mounted Stop Lamps in Passenger Cars and Light Trucks


Executive Summary

1.Introduction and Background

    1.1 Evaluation of CHMSL
    1.2 Results of earlier effectiveness and cost studies - passenger cars 2
    1.3 Extension of CHMSL to light trucks

2. The initial and long-term overall effectiveness of passenger car CHMSL

    2.1 Data sources
    2.2 The basic contingency table
    2.3 Controlling for the vehicle age effect
    2.4 Computation of the preliminary effectiveness estimates
    2.5 Tests for spurious effectiveness before MY 1985 and after MY 1986
2.6 Adjusting the estimates for retrofits and other factors
    2.7 Confidence bounds and statistical tests - based on State-to-State and CY-to-CY variation of the   effectiveness estimates
    2.8 Confidence bounds and statistical tests - based on an eight-State, paired-comparisons estimator
    2.9 Comparison with earlier analyses

3. The effectiveness of passenger car CHMSL in specific situations

    3.1 Analyses of five State files: method
    3.2 Analyses of five State files: results
    3.3 The effect of CHMSL in fatal crashes

4. The effectiveness of CHMSL for light trucks

    4.1 Analyses of six State files: method
    4.2 Overall effectiveness
    4.3 Effectiveness by truck type and size

The long-term benefits and costs of CHMSL



This document is available to the public from the National Technical Information Service, Springfield, Virginia 22161.The United States Government does not endorse products or manufacturers. Trade or manufacturers' names appear only because they are considered essential to the object of this report.