Higher speed increases the risk of crashing and the severity of the crash. Many fatal crashes and single vehicle crashes, e.g. running off the road, are in some way caused by speed.
Speed limits are set according to the quality of the road and tell you the maximum speed allowed in good conditions. You’re never allowed to exceed the speed limit - it’s illegal.
Electronic variable signs have a changeable electronic display that shows the current speed limit. The speed limit will change depending on the current traffic conditions (e.g. congested traffic, bad weather etc.) and are often located on freeways, in tunnels and outside of schools.
Not all roads have speed signs. An end speed limit sign or speed de-restriction sign will indicate that you are entering an area with no speed signs.
If there is no signed speed limit, one of two default speed limits will apply:
The default speed limit in built-up areas is 50 km/h unless otherwise signed. A built-up area can be recognised by having buildings or street lights next to the road.
The default speed limit for roads outside of built-up areas is 100 km/h unless otherwise signed.
A local traffic area consists of local streets with a speed limit of 40 km/h. Stay alert for pedestrians, children or bicycle riders etc.
Children are unpredictable, may be unaware of road rules and can fail to recognize dangerous situations on the road. Therefore, lower speed limits are imposed near schools to protect children from fast travelling vehicles.
Time-based speed signs only apply during certain hours on school days. The speed limit is usually 40 km/h. Some signs use twin yellow flashing lights to indicate when the school zone is in operation.
Shared zones are meant to protect pedestrians by limiting the speed and forcing drivers to give way to all pedestrians within the zone (i.e. pedestrians have total priority over other traffic). The speed limit is 10 km/h for shared zones unless otherwise indicated.
An advisory speed limit tells you the maximum speed that’s safe to drive in good conditions. You’re recommended to reduce your speed temporarily and display caution to get past safely. Generally placed before bends, curves and crests etc.
Variable message signs are electronic signs that are placed overhead of or next to some roads, and provide early warnings and messages to create a safe and efficient traffic flow. They alert road users to changes in traffic conditions, e.g. crashes, road works, congestion and road closures.
There are reduced speed limits for learner and provisional licence holders in NSW:
You must not obstruct vehicles behind you by driving unreasonably slow (e.g. 30 km/h on a 100 km/h road) unless the conditions require you to.