Citation

Richards SH. Transp. Res. Rec. 1981; 819: 22-30.

Copyright

(Copyright © 1981, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Existing driveway standards include independent design controls for throat width and curb return radius. They fail to recognize that these two driveway features may have an aggregate effect on driveway operation. In addition, current standards for driveway width and curb return radius are based primarily on vehicle turning capabilities and do not consider how drivers respond, in terms of speed and path, to various driveway designs. The results of proving-ground studies conducted to evaluate the effects of driveway width, curb return radius, and offset taper approach treatments on the speed and path of drivers entering and leaving driveways are presented. A total of 59 nonprofessional drivers participated in the studies. These motorists, driving an instrumented study vehicle, collectively performed more than 1400 driveway entry and exit maneuvers. Speed and path data were collected for each maneuver and were analyzed to determine the relative performance of 19 driveway design conditions. The studies revealed that current standards for driveway width and radius result in driveway designs that encourage very slow entry speeds and, in many cases, undesirable vehicle paths. Recommendations are presented, based on the study results, for driveway width and radii requirements. The studies also found that offset taper approach treatments do not have a significant effect on entry paths or speeds at driveways.