Guidelines for right-turn lanes on urban highways: Ataullah, Syed, Ph.D. The University of Nebraska-Lincoln, 1993. 119 pp. supervisor: Patrick T. McCoy

Abstract

Guidelines for the use of right-turn lanes at access points on urban two-lane and four-lane roadways were developed. The guidelines define the design-hour traffic volumes for which the benefits of right-turn lanes exceed their costs. The benefits used in the analysis were the operational and accident cost savings that right-turn lanes provide road users. The operational cost savings were those associated with the reductions in stops, delays, and fuel consumption experienced by through traffic. The accident cost savings were those associated with the reduction in accidents expected from the lower speed differentials between right-turning and through traffic. The guidelines define the right-turn design-hour volume required to justify a right-turn lane as a function of the following factors: (a) directional design-hour volume, (b) roadway speed, (c) number of lanes on the roadway, and (d) right-of-way cost. Comparison with guidelines developed by others indicates that the guidelines developed in the research are within the range of existing guidelines. In addition they are more definitive than the other guidelines because they account for the effects of roadway speed and right-of-way costs.