Exceeding the Speed Limit

It is an offence for a driver to exceed the speed limit that applies to the driver over the relevant length of road [Australian Road Rules r 20].

The penalty may vary depending on the area or zone in which the speeding offence is committed. SA Police may issue an expiation notice to a driver caught exceeding the speed limit.

Fines and demerit points apply in increasing amounts where a driver:

Where a driver exceeds the signed speed limit by 45 km/h or more, they may be charged with the offence of driving at excessive speed. See Excessive Speed.

To see the current expiation fees, demerit points and victims of crime levy that apply to speeding offences, see the SA Police Expiations websiteand Expiable Offences and Fees - Traffic (PDF download).

Default speed limits

A speed limit sign often indicates the speed limit [Australian Road Rules r 20]. If there are no signs, the default speed limit applies. In a built-up area, the default speed limit is 50 km/h. In all other areas, the default speed limit is 100 km/h [Australian Road Rules r 25].

There are also some special speed limits that apply to certain classes of vehicles, for example buses exceeding 5 tonne gross vehicle mass (GVM) and vehicles exceeding 12 tonne GVM must not exceed 100 km/h.

Speed limit when passing certain stopped vehicles

Drivers must slow to 25 km/h (or a lesser speed if necessary to avoid endangering a person) when driving through an emergency service speed zone [Road Traffic Act 1961 (SA) s 83].

An emergency service speed zone is an area of road:

A driver will not need to slow down if they are driving on a road divided by a median strip and the emergency service speed zone is on the other side of the road [s 83(2)].

Drivers must also slow to 25 km/h when passing a school bus that has stopped on a road to collect or drop off children [s 82].

From 19 May 2025, drivers are required to slow to 25 km/h when passing a breakdown services vehicle that has stopped on the road and is displaying a flashing amber light [s 82A].

A breakdown services vehicle is a vehicle used to provide breakdown services (such as repairing or removing a broken down car). This includes RAA vans and tow trucks.

The requirement to slow to 25 km/h when driving through an emergency service speed zone or past a school bus or breakdown services vehicle does not apply to the driver of an emergency vehicle provided they are taking reasonable care [see s 110AAAA and Road Traffic (Miscellaneous) Regulations 2014 (SA) reg 61B].

A driver will not be charged with an offence of driving at excessive speed if they exceed a 25 km/h speed limit by 45 km/h or more provided they do not exceed the usual speed limit for the road by 45 km/h or more [s 45A, reg 61AAA].

Penalty

The maximum penalty for any of the speeding offences described above is a fine of up to $2,500 [Road Traffic Act 1961 (SA) s 164A].

To see the current expiation fees, demerit points and victims of crime levy that apply to speeding offences, see the SA Police Expiations websiteand Expiable Offences and Fees - Traffic (PDF download).

Further offence of dangerous driving

Drivers who excessively speed may also be charged with an offence of dangerous driving [Road Traffic Act 1961(SA) s 46]. See Dangerous driving.

Proof of speeding

Police will generally seek to prove a speeding offence through use of radar, laser devices, speed cameras or through the observation of a police officer. Speed cameras must be set up and photographs processed in accordance with the Road Traffic (Miscellaneous) Regulations 2014 (SA) [regs 32-36]. There are also provisions to allow better detection of speeding on rural highways through the use of average speed evidence [Road Traffic Act 1961 ss 79B, 175A]. Average speed evidence is calculated by measuring the speed of a vehicle between two separate speed camera locations rather than at a single point. Average speed camera locations can be situated from 14 to 50 kilometres apart.

An expiation notice will be sent to the registered operator of the motor vehicle who must be given the opportunity to view the photograph. If they are not the driver, they can complete a declaration nominating the actual driver. These photographs can be viewed online via the SA Police Expiation Self-Service Portal.

Other devices used to measure speed must be approved and also properly calibrated. A driver may be able to defend an offence if the police did not comply with these procedures. Seek legal advice in these circumstances.

Specific evidentiary issues existed in 2018 in relation to the use of Lidar devices (devices used to measure speed). The evidentiary issue was rectified by the insertion of section 175(3)(baa) into the Road Traffic Act 1961 (SA) which commenced on 14 December 2018. Anyone affected by the evidentiary issue relating to the Lidar devices should seek legal advice.

Road Works

Expiation notices may be issued for speeding where a driver exceeds the speed limit of a temporary traffic control sign, such as those used in areas of road works. Where reduced speed limit signs are placed on a road in relation to road works, the speed limit signs are of no effect during any period where workers are not engaged at the road works site, and the area of road affected by the road works does not involve a greater than normal level of hazard [Road Traffic Act 1961 (SA) s 20(11)(b)]. This means that, if the usual speed limit is 50 km/h but signs are placed near road works on that length of road indicating a speed limit of 40 km/h past the road works, then a person travelling at 60 km/h on that length of road will not be fined for exceeding the speed limit by 20 km/h, unless workers are engaged at the site or the site presents a greater than normal hazard. Workers will be taken to be engaged at the site if they are physically present in the area, or if they have been temporarily absent from the area for a period not exceeding 2 hours [s 20(15)]. Even if the driver is not fined for exceeding the speed limit by 20 km/h, they may still may still be guilty of exceeding the speeding limit by 10 km/h (as they drove 60 km/h and the usual limit is 50 km/h) and may be fined accordingly.

Beach speed limits

Unless otherwise signposted, the speed limit on beaches that permit driving is 40 km/h, or 25 km/h when within 50 metres of a person. The maximum penalty is a fine of $5,000 [Road Traffic (Road Rules - Ancillary and Miscellaneous Provisions) Regulations 2014 (SA) reg 8A]. The offence is expiable and attracts demerit points - see Expiable Offences and Fees - Traffic (PDF download).