Citation

Ricker ER. Highw. Res. Board bull. 1956; 127: 15-18.

Copyright

(Copyright © 1956, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

The rear lighting of vehicles was evaluated as it pertains to expressway operation to determine the adequacy of existing lighting requirements. The requirements of the various states and the interstate commerce commission were studied. Data were collected as to the candle power and condition of rear lighting on trucks. Present legal requirements for the intensity of rear lighting are stated either in terms of visibility distance during night operating conditions or by bench measurements of candle power measured at certain angles to the lamp axis. These methods do not take into account many variables encountered in practical truck operations. An experimental photometer was constructed to make direct measurements of the output of vehicle tail and stop lights. It consists of a baffled photometric tube, lens, barrier-layer cell, microammeter and appropriate switches and circuitry. Data were collected using this photometer over a period of several months on vehicles traveling over the Pennsylvania and New Jersey turnpikes. These data are summarized in tables. The study is continuing with proposals on definite requirements as to the intensity placement and use of tail and stop lights for vehicles traveling on the various turnpikes.