In Victoria, the Road Safety (Traffic Management) Regulations prescribe requirements for the authorisation of traffic control devices, including speed limit signs. Speed limit sign sizes are categorised by codes ranging from A (smallest) to E (largest). Selection of the appropriate sign size is determined by the applicable speed zone, where sign sizes generally increase with speed limits. Various environmental and traffic conditions may warrant variations, such as, for exampl

The relationship between vehicle speeds, crash risk, and injury severity is well known and is a key topic that continues to be examined heavily in road safety research. Generally, both crash risk and injury severity risk increase with higher speeds. This is a fundamental driver of various efforts to reduce speeds and speeding through a combination of engineering, enforcement, education and regulatory measures. The benefits of speed reduction measures may be crudely estimated