Citation

Elmberg CM, Michael HL. Highw. Res. Board bull. 1961; 303: 1-9.

Copyright

(Copyright © 1961, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

This paper reports the results of a study at five suburban areas of the combined effect of various speed limits and roadside development on driver speed patterns. Three of the locations concerned were two lane u.S. Highways traversing suburban development of predominantly residential, commercial, and industrial type, respectively. One location was a four-lane partially divided highway recently reconstructed from two lanes to four lanes. No speed limits had been posted along this highway after the reconstruction had been completed. Consequently, this highway was an excellent location for studying the effects of various posted speed limits, making possible comparisons between unrestricted and restricted speeds. Only free moving passenger vehicles traveling on dry pavement under optimum day and night visibility conditions were considered. Speed patterns for local and non-local vehicles were analyzed separately, local vehicles being those officially registered in the actual county as verified by the prefix on the license plate. Spot speeds were recorded, using an electro- matic radar speed meter, at various points at each location, during day and night, before and after speed limit signs had been posted. Altogether, 31,573 vehicles were recorded, of which 20,552 were during the day and 11,021 were during the night. The study revealed that the drivers paid little, if any, attention to posted speed limits. They seemed to choose a speed which they themselves considered appropriate for prevailing conditions. Non-local vehicles traveled significantly faster than local vehicles in many instances. Noticeable differences between day speeds and night speeds were also recorded at some sites. Variabilities in the speed distribution at a few individual stations for the same sign and road conditions were unexpectedly high, thus somewhat challenging the accuracy of fixed-point speed measurements. The influence on the speed pattern of various types of roadside development was difficult to distinguish intelligibly, and was evidenced by the revelation of distinct interaction effects between the diverse factors. The limited number of locations, adequate for the roadside development study, also contributed to making difficult an ultimate conclusion.