As part of any program of speed management and enforcement, it is important to ensure that speed zoning is rational and consistent. Those responsible for zoning decisions are often faced with competing pressures and demands from particular interest groups. At the same time there is a lack of clear guidelines to the public and local authorities on what is an appropriate zone for particular conditions. This report describes the development of a computer `advisor' program which can indicate the probable zoning decision a group of experts would make in a given situation. The advisor is based on an `expert system', backed up by extensive data collection and investigation of the zoning decision process. Field measurements were taken of road cross section, abutting development and traffic speeds at 64 sites covering a wide range of road types and environments. Upstream and downstream road features were also noted. A number of panel discussions were held with the road traffic authority and the victorian speed limits committee. These used slides of existing zones, current rezoning applications, and discussion of the zoning decision process to determine the factors which should be used to discriminate in particular cases. The resulting `advisor' program is able to reproduce the experts' decisions in the majority of cases, and can indicate cases where the decision is marginal. The advisor is highly user friendly, requiring no computer knowledge and providing a menu of response alternatives for most questions. Field data sheets are also provided to assist the user in site inspections. The research highlighted the importance of abutting development in speed zoning decisions, and found a number of anomalies in existing speed zones (A). The ISBN of the microfiche version is 0-86910-356-3.
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