The optimum speed is defined as one which balances the social costs and benefits of increased travel time with decreased road trauma, vehicle operating costs, emissions, etc. The project focused on urban residential streets with 60 kmh speed limits because of the availability of a considerable amount of relevant basic data. Three different methods were considered to measure the impact of travel speed on road trauma and/or crash costs (Kloeden et al 1997, Nilsson 1984, Kallberg and Toivanen 1998). The relationships between cruise speed and average (all) speed found by SMEC (1998) were extrapolated to measure the impacts on travel time in residential streets for travel speeds in the range 35 to 85 kmh. The relationship between vehicle operating costs and travel speed was based on two Australian models given by Thoresen (2000). Air pollution emission rates at each travel speed were based on European relationships given by Ward et al (1998).
Type: Research and Analysis Report
Sub Type: Grant
Author(s): M Cameron
Topics: Economic, Speed
Publication Date: 01/01/02