Citation

Hall JW, Dickinson VL. Transp. Res. Rec. 1974; 486: 19-32.

Copyright

(Copyright © 1974, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The research reported in this paper was designed to evaluate the effectiveness and desirability of the differential truck speed limit on Interstate facilities in Maryland and to examine the operational implications of changing this limit. The research effort was directed toward (a) determining the degree to which trucks comply with existing speed limits, (b) developing a procedure for comparing truck speeds and accident rates on particular sections of highway, and (c) determining the likely operational impact of modifying differential truck speed limits on Interstate highways. Vehicular speed and accident data were collected and analyzed for 84 study sites located on Interstate, U.S., and state routes throughout Maryland. Multiple regression techniques were used to determine whether a significant relationship could be found among speed parameters, accidents, and accident rates. Attempts were made to develop models for the prediction of truck accident rates on limited-access facilities. The existence of a posted differential speed limit was not found to be related to truck accidents, although truck compliance with the differential limit was comparatively low. It was not possible to develop a statistically significant equation for the prediction of the overall rate of truck accidents. Significant equations that are capable of explaining truck accident and involvement variables by changes in traffic speed parameters were developed. The impact of modifying the differential truck speed limit could not be determined with certainty, but it was suggested that the limit be temporarily altered on a test section.