Speed is a key factor in crashes and road trauma. The default speed limits in Australia have been set in response to research findings that have revealed direct correlation between travelling at speed and the increased risk of crash and trauma. In acknowledging safer speed limits and travelling at appropriate speeds on South Australian roads, we are all contributing to making our roads safer for all road users.

Know the speed limits

Speed limits indicate the maximum vehicle speed that is permitted on that road. These default speed limits are applied in South Australia and across Australia. Any road with a speed limit different to the default limit is signposted accordingly. 

Speed limits in South Australia
	25 km/h between the signs at a children’s crossing when the alternating lights are flashing when passing, in either direction, a school bus that has apparently stopped to pick up or set down passengers on a portion of road within a School Zone when a child is present (or as indicated) when passing road works with signs displayed.
	40 km/h some built up areas (eg residential areas) have a speed limit of 40 km/h indicated by signs on all roads leading to that area on the approach to a ‘wombat’ pedestrian crossing indicated by signs when passing, in either direction, an emergency services vehicle(s) that is stationary and displaying red/blue flashing lights
	50 km/h is the general default speed limit in a built-up area is the maximum speed limit on roads within a built up area unless a signposted differently.
	100 km/h is the maximum speed limit on roads outside a built-up area where no other speed limit is signposted.  is the speed limit on most rural roads in South Australia.
In built-up areas, some roads may have a higher speed limit (eg 60 km/h or 80 km/h) shown by speed limit signs. Variable electronic speed limit signs also operate throughout South Australia. Some roads may be signposted at 110 km/h. This does not apply to the following: ‘L’ plate drivers must not exceed 100 km/h All ‘P’ plate drivers must not exceed 100 km/h Drivers of buses of more than 5 tonnes Gross Vehicle Mass (GVM) and heavy vehicles of more than 12 tonnes GVM must not exceed 100 km/h A longer or wider vehicle, such as a road train or low loader, may have a lower maximum speed limit as a condition of its permit of travel.

What you can do about speed limits

The speed limit is the maximum permissible speed you are allowed to drive a vehicle, providing it is safe, on roads and road related areas such as a car park. To drive at safe speeds, always:

• observe the speed limit signs, wherever you are driving
• consider the weather conditions and reduce your speed accordingly. Extreme weather such as strong wind, storm, dust, fog and ice make driving a hazardous task
• adjust your driving speed to suit the type of road you are driving on - its surface, width and condition
• consider the traffic conditions. Travelling at the maximum speed limit is risky during peak hours and when you are sharing the road with slow moving vehicles, including cyclists and motorcyclists
• be alert for pedestrians, especially children and the elderly, who may behave unpredictably in the road environment
• be aware of other road users, such as cyclists, whose safety on the road may be affected by drivers passing or overtaking them at high speed
• drive at speeds that are safe for your own driving ability
• consider the quality of life for residents that can be badly affected by cars and/or motocycles speeding past their homes.

Further information on Driving offences and penalties