Citation

Yagar S. Transp. Res. A Gen. 1984; 18(1): 61-70.

Copyright

(Copyright © 1984, Elsevier Publishing)

DOI

10.1016/0191-2607(84)90094-3

PMID

unavailable

Abstract

A procedure is developed for estimating highway speeds as a combined function of both traffic volumes and the geometric and environmental conditions surrounding the highway. The proposed method applies a general set of passenger car equivalent units (pcu's) for trucks, recreational vehicles, and opposing flows, in order to reduce traffic volumes to a single variable, which can then be introduced at either an average level, or at contrasting high and low levels, along with geometric/environmental conditions into a multiple linear regression equation which treats all of the factors simultaneously. The procedure is applied to estimate various speeds om rural 2-lane highways inOntario, using a data bank compiled in 1980. Equations are developed for the 10th, 50th and 90th percentile operating speeds. Speeds in Ontario are found to be affected by: traffic volumes, by direction and type of vehicle; access to adjacent land use; access from other highways; speed limit; existence of an extra lane; and grade These Ontario findings are tempered by a lack of severe grades on high-volume roads, and by standard road widths. Thus is recommended that the described procedure be re-applied in another jurisdiction using data which incorporate a wider range of grades, and road widths.