A systematic and ongoing method of measuring vehicle speeds was introduced in South Australia in 2007 in order to assess the effects of speed reduction countermeasures and to monitor the speed behaviour of South Australian motorists over time. This Report summarises the data collected in 2012 and makes comparisons with previous surveys and partial surveys dating back to 2002. Low speed roads showed a marked reduction in mean speed following the introduction of the default 50 km/h speed limit in 2003 and for some years after. Mean speeds on these roads generally went up from 2005 to 2007 but down again in 2008. Mean speeds on these roads remained relatively unchanged between 2008 and 2009. The metropolitan roads showed a reduction in speeds between 2009 and 2010. No change was evident between 2010 and 2011. Mean speeds on metropolitan local roads went down in 2012. The speeds of vehicles on high speed rural roads remained relatively unchanged between 2006 and 2011 with the exception of a small but statistically significant increase in the speeds of vehicles on 110 km/h roads between 2010 and 2011. Mean speeds on both 100 and 110 km/h roads decreased in 2012. It is not clear what the reasons for all of the observed speed changes are although the lowering of the police enforcement tolerance in 2008 and a large advertising campaign may have played some role in the speed changes between 2007 and 2008. (Author/publisher)
Abstract