Potential Benefits and expenses of Speed Changes on Rural Roads

The objective of the project was to explore the potential economic costs and benefits of changes to speed limits on rural roads in Australia. Net costs and benefits were estimated over a range of mean travel speeds (80 to 130 km/h) for the following road classes:

• freeway standard rural roads (dual carriageway roads with grade-separated intersections and a design speed of 130 km/h, usually designed as such when originally constructed


• other divided rural roads (not of freeway standard)


• two-lane undivided rural roads (two illustrative ‘road stereotypes’ with different crash rates).


Specific objectives were to explore a number of scenarios, such as:


• increasing limits on high standard roads with a low crash rate (per vehicle-kilometre) from 110 to 130 km/h (or intermediate speeds)


• increasing limits on high standard roads with a low crash rate from 110 to 130 km/h subject to a variable speed limit system that would reduce speeds under adverse conditions such as poor light, bad weather or dense traffic (‘VSL option’)


• decreasing limits on lower standard rural roads with higher crash rates.