ARSRPE Conference Paper Database

The impact of lowered speed limits in urban areas

Archer, J, Fotheringham, Nicola, Symmons, Mark, Corben, Bruce



The increasing and sometimes conflicting goals of the transport system such as overall performance and efficiency, mobility, safety and environmental sustainability, have become increasingly difficult to achieve without major investments in the road infrastructure. New and affordable ways of reducing levels of road trauma that have a minimal impact on mobility are keenly sought by the Australian Government, federal and state road authorities and by society at large. This particular literature study addresses a number of the issues surrounding a lowering of speed limits in urban areas; a relatively low-cost measure that is likely to have a positive impact on safety but also a negative impact of some magnitude on mobilty. The relationship between vehicle speed and accident outcome severity is well established. A major study conducted by the OECD and the ECMT in 1996 concluded that speeding is the number one road safety problem in most countries around the world, and that reductions in average speeds of approximately 5 per cent would yield a reduction in fatalities by as much as 20 per cent (OECD/ECMT , 2006). Research also indicates that even modest speed reductions can prevent the occurrence of collisions and significantly reduce the outcomes of those crashes that do occur; particularly those that involve vulnerable road-users who are more predominant in the urban environment (e.g. Kloeden, et al. 1997, 2001; Elvik, 2002; G?rder, 2004; Racioppi et al. 2004). In addition to safety, there are other potential benefits to be gained by speed limit reductions in urban areas. Those suggested in the literature include an increase in traffic flow and consequent reduction in congestion and delays, particularly where the roads are functioning at near capacity. Further, reductions in speed bring about a reduction in vehicle operating costs with less wear and greater energy (fuel) efficiency, and less pollution and noise (see e.g. Carlsson, 1997; Kallberg and Toivanen, 1998; Cameron, 2000; Elvik and Vaa, 2004).