Citation

Normann OK. Highw. Res. Board bull. 1958; 195: 8-13.

Copyright

(Copyright © 1958, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

Variables in automobile design are discussed in relation to the present practices of marking no-passing zones on two- lane highways. One of the advantages in the recent increase in the horsepower of passing cars is the ability to complete passing maneuver in less time, thus reducing the possibility of being caught in the left lane of a 2-lane road with an oncoming vehicle rapidly reducing the time interval between life and death. This is closely allied with the lower height of the driver's eyes in the newer cars which, under certain highway conditions, reduces the distance that the driver can see a clear road ahead. Data were collected from a comprehensive series of investigations of passing practices on 2-lane highways. Detailed data were recorded for a total of 21,000 passing maneuvers at 32 locations in 7 states between 1938 and 1940. Data were obtained during recent studies by manual observations. The speeds of both the passed and passing vehicles were higher in 1957 than in 1938. However, the time spent in the left-hand lane by the newer vehicles in 1957 was 0.5 sec shorter than the time in 1938. The distance traveled in the left lane, increased 100 feet. It is concluded that there is little evidence to indicate that present practices of marking no-passing zones should be changed due to the changes that have taken place during the past years in vehicle design and driver performance.