A trial of a reduced maximum speed for trucks on the princes highway between Melbourne and Geelong

Excessive speed is estimated to account for 36% of crashes in which the driver of a heavy vehicle was killed. In 2013, the Transport Accident Commission undertook, with assistance from the Victorian Transport Association and several heavy vehicle operators, a trial of reduced speed limits for trucks traveling along a 43.5 km stretch of the Geelong Freeway to evaluate the effects of speed reduction on speed behaviour, fuel consumption, travel times, and driver acceptance and attitudes. Six drivers of five trucks participated in the study. During the first 11 weeks, all trucks travelled up to the legal speed limit of 100km/h. In the following 10 weeks, three trucks reduced their maximum travel speed: two to 90 km/h, and one to 95 km/h. Two control trucks maintained the legal speed limit of 100 km/h for the entire trial. Evaluation methods included face-to-face interviews with drivers and operations mangers, an on-line survey of community attitudes, on-board video surveillance as well as analysis of truck speed data and fuel consumption data. The reduced maximum speed of travel was associated with reductions in fuel consumption, crash risk, and generally positive attitudes from the drivers, operations managers and other road users. Only small increases in average trip times at the reduced speeds were observed. Drawbacks included greater difficulty overtaking or changing lanes, tailgating by other vehicles and an increase in the number of safety-related events when other vehicles merged onto the freeway. These appeared more pronounced at the 90 km/h reduced maximum speed than at 95 km/h.