Citation

Taragin A. Highw. Res. Board bull. 1958; 170: 54-76.

Copyright

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

DOI

unavailable

PMID

unavailable

Abstract

A study was conducted to obtain information regarding driver behavior and bearing on safety of operation on two- lane roads when the shoulders are paved with the same material as the traffic lanes. This information is compared with similar information for two-lane roads having shoulders that appear distinctly different from the traffic lane. Data were collected on speeds and placements of all vehicles as they passed a selected point of observation. Observations were made of passing maneuvers at a limited number of locations. Special studies were made of the effect of edge stripes on vehicle speeds and placements.

RESULTS show that vehicle speeds were not affected by the shoulder width and height. However, a relation did exist between vehicle speeds and lateral position on sections where the shoulders were paved to their full width. Commercial vehicles encroached on the shoulder to a greater extent than passenger cars. The concentration of lateral positions of vehicles increased with an increase in the difference in appearance between the traffic lanes. Shoulder edge stripes closer than 1.5 feet from the outside edge of bituminous pavements paved to their full shoulder width have no effect on vehicle speeds or lateral positions. A 2-inch solid white stripe painted eight feet from the outside edge of the shoulder or twelve feet from the centerline of the pavement on the roads paved to their full shoulder width was found to be very effective in keeping vehicles in travel lanes, thus reducing shoulder encroachment by about 50% as compared with no edge stripes. On a two-lane 24-foot bituminous pavement with 4-foot bituminous shoulders different in appearance from the traffic lanes and with six feet of gravel outside the paved portion of the shoulder, a 4-inch solid yellow stripe thirteen feet from the center of the surface was very effective in reducing shoulder use, especially by trucks.