Speed management contributes to road safety, mobility and amenity on public
roads and involves
- setting of speed limits (Transport SA’s Metropolitan Region)
- enforcement (Police)
- education (Transport SA’s Safety Strategy section).
Speed limits are set for the safety of all road users. Setting
speed limits that are appropriate for the conditions can reduce the number and
severity of crashes.
Speed limits are set to maintain a balance between
- a driver’s reasonable perception of the speed environment (what the
‘average motorist’ believes is a safe travelling speed for that
- an acceptable level of environmental amenity for all road users and the
surrounding land usage.
Speed limits are also set so as to encourage a uniform speed of travel
to lessen the differences in speed between cars travelling on the same road
and reduce the need for overtaking.
Factors in establishing speed limits
- road function
- existing traffic speeds.
- speed environment (elements which influence a driver’s perception
of an appropriate maximum travel speed) eg
- roadside development in terms of type and density
- road characteristics, including
- standard of design and construction
- frequency of intersections
- type and frequency of access from abutting development
- parking provisions and activity
- traffic characteristics including
- composition (including cyclists and pedestrians)
- road crash history.
A poor crash history will often indicate the need for counter
measures other than changes to the speed limit.
Where the speed limit exceeds the maximum safe speed
of travel, eg negotiating corners or bends, advisory
speed signs displayed in conjunction with the relevant
warning signs advise drivers of the need to reduce speed.
Speed limits in South Australia
Speed limits range from 10 km/h up to 110 km/h depending on
- the purpose of the road (ie a main route)
- type and volume of traffic
- the surrounding environment (passing through residential, school, or industrial
- shared pedestrian / vehicle zones on local streets
- School Zones
- Emu Crossings
- Koala Crossings
- generally at roadworks
- Wombat Crossings
- some residential streets and holiday home areas (eg Yorke Peninsula)
- as part of a local area precinct limit
- as determined by Councils
- general urban limit applicable to all roads in built-up areas, unless otherwise
60, 70, 80 and 90 km/h
- some traffic routes of a higher standard
- general rural speed limit which applies on country roads except in built-up
areas, in the absence of speed limit signs
- maximum signposted speed limit permitted in South Australia