DESIGN SPEED, SPEED LIMIT AND COSTS ON RURAL FREEWAYS

The questions of an appropriate speed limit and a design speed for rural freeways are discussed. Sections of five freeway schemes, which between them are located in a variety of topographies, were selected for investigation. These sections were redesigned to different design speeds and the construction costs of each alternative estimated. The total operating costs for each alternative design were computed at different speed limits. It is recommended that: the maximum rural speed limit should be reduced to 90 km/h; traffic authorities should raise the level of enforcement; the National Road Safety Council should conduct a campaign supporting lower speed limits; and road authorities should not use a rural freeway design speed of less that 120 km/h. For the covering abstract of the conference see IRRD 288720. (TRRL)