Rural roads without a median barrier should have a 70km/h speed limit, according to new report by the International Transport Forum that studied data from 10 countries including Australia.
The report found in all 10 cases that crashes, injuries and fatalities decreased when speed limits were dropped and speed camera use increased.
According to a scientific formula, it shows that every 1% increase in average speed results in a 2% increase in all injury crashes, a 3% rise in fatal and severe crashes and 4% more fatal crashes.
It not only recommends the 70km/h rural roads speed limit, but also 30km/h in city streets with high pedestrian use and 50km/h on urban roads.
Their recommended speed limits are based on the “Safe System” principles that speed should be set “at a level that humans can survive without dramatic consequences in case of a crash”.
The report also notes that “lower driving speeds generally improve citizens’ quality of life, especially in urban areas”. They also reduce emissions, fuel consumption and noise, it says.
Reducing speed limits on rural roads to 70km/h may be understandable in some densely populated countries.
But in our sprawling nation, it would bring our transport system and our economy to a halt.
It would also sound the death knell for motorcycling.
Australian case study
The Australian case study is based on data from 1997 to 2003 where urban speed limits dropped from 60km/h to 50km/h (except in the Northern Territory) and speed camera use increased.
It found that the mean speed decreased by 0.5 km/h, while the total number of crashes decreased by 25.3% and the number of persons injured by 22.3%.
There were differences between states:
- NSW mean speed reduction of 0.5-0.9km/h resulted in a 22% casualty crash reduction;
- Victoria 2-3km/h reduction resulted in a 12% reduction;
- Perth 0.3km/h led t a 21% drop;
- Regional Western Australia 3km/h – 16%;
- South Australia: 3.8km/h and 2.1km/h drop on unchanged arterials ed to a 23% crash drop; and
- Queensland there was no relevant crash data for the 6km/h mean speed drop.
The study also found that the reductions in the proportions of vehicles exceeding 60, 70 and 80km/h speed limits were more substantial than the reduction in mean speed.
It accredits this to strong enforcement of urban speed limit reductions.
No doubt the authorities will be quoting this survey endlessly as they camp down further on speed limits and ramp up the use of speed cameras.
Covert cameras
The study also suggests that covert speed cameras are most effective in cash reduction, based mainly on statistics from Victoria which leads the country in speed camera revenue:
Looking at severe crashes, the covert use of mobile speed cameras in Victoria, Australia, has been shown to be very effective in reducing injury crashes and fatal outcomes (Cameron and Delaney, 2008). Recent research has also shown that only 7% of injury crashes in Melbourne are now attributable to high-level speeding, compared with 24-34% in other Australian major cities where mobile cameras are operated less effectively (Cameron, 2015).