Citation

Harwood CJ. Road Transp. Res. 1995; 4(2): 88-96.

Copyright

(Copyright © 1995, Australian Road Research Board)

DOI

unavailable

PMID

unavailable

Abstract

There seems to be broad agreement that the principal aim in reviewing the general urban speed limit is to set limits that are appropriate for different road environments. It is less clear what criteria should be used in setting the level of a general speed limit. While speed zones are dealt with in some detail in the published literature, including the Australian Standard Manual of Uniform Traffic Control Devices, there appears to be little guidance on the selection of an appropriate level of general speed limit. This paper draws some distinctions between general speed limits and speed zones, and presents a suggested approach to the selection of appropriate levels for general speed limits. Surveys of the free speeds of fifty vehicles each were conducted at about thirty sites both on local access streets and on arterial roads within the substantially built-up suburbs of the Adelaide Metropolitan area. All sites were randomly selected. Mean speeds and the proportions of the samples that were below designated speed levels (compliance levels) were compared for the local and arterial roads. The results cast some light on the implied relative emphasis placed on existing vehicle speeds for two different notional levels of speed limit in local streets (40 km/h and 50 km/h).