Citation

Polus A, Eck RW. Transp. Res. Rec. 1987; 1122: 12-17.

Copyright

(Copyright © 1987, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Design measures, operational characteristics, and economic considerations applicable to the selection of geometric design alternatives are reviewed. The discussion is based on recent research of driver behavior and a hypothetical analysis of level of service as related to invested capital. Geometric design measures are closely related to operational characteristics as well as to economic considerations. Unless ample sight distance is provided throughout a facility, some variability of speeds may be expected. Driver workload is increased and performance is likely to deteriorate without sufficient sight distances. The relationship of speed characteristics on two-lane roads to overall geometric measures such as average curvature and hilliness and to traffic parameters such as volume and traffic composition was established. To increase safety and operational uniformity, consistent speeds should be the goal of designers. The magnitude of acceleration noise may be predicted by overall measures representing design consistency, such as the ratio between minimum and maximum radii or the ratio of the sum of lengths of curves to total section length. Predicted acceleration noise for different alternatives may serve as a potentially adequate measure for evaluating the merits of various designs. Based on a hypothetical logistic-type relationship between investment magnitude and level of service, suggestions were made for the level of service to be adopted for design purposes. Because of diminishing returns for a high level of service, an intermediate level of service may be desirable if purely economic considerations govern planners' decisions.

Record URL:
http://onlinepubs.trb.org/Onlinepubs/trr/1987/1122/1122-002.pdf

TRT Terms: Alternatives analysis; Economic factors; Geometric design; Highway curves; Highway design; Highway safety; Level of service; Operations; Sight distance; Speed
Old TRIS Terms: Economic considerations; Operational effects
Subject Areas: Administration and Management; Design; Economics; Highways; Planning and Forecasting; I21: Planning of Transport Infrastructure;

Language: en

Keywords

HIGHWAY ENGINEERING; HIGHWAY SYSTEMS - Accident Prevention; HUMAN ENGINEERING - Behavioral Research