Road Safety
- Publication no: AGRS03-26
- ISBN: 978-1-923617-36-0
- Published: 18 February 2026
- Edition: 2.1
- Superseded
- PDF (free) Download
Speed management to ensure safe travel speeds is fundamental to achieving Safe System and ensuring that people do not die on our roads (Vision Zero). The Guide to Road Safety Part 3: Safe Speed Management provides an overview of the importance of speed management for road safety, of speed limit reviews, changes, and application as a speed management tool, as well as interventions to ensure compliance with safe speed limits. Speed limits are a foundational tool is speed management and the use of appropriate speed limits forms an integral part of a safe road system. They are one of many speed management tools used to improve road safety, while maintaining the efficiency of the road network. The guide also addresses the complexity of manage speed across disparate pillars of road safety management, with vital roles being played by Safe Roads and Roadsides, Safe Vehicles, and Safe People, as well as Safe Speeds.
Within the context of a safe road system, speed limits must accommodate the varying types of road users, the road and roadside environment, possible crash types, types of vehicles driven and the safety, amenity and economic needs of the community.
The general philosophy adopted to date when setting speed limits is that when they are being assessed they take into consideration a comprehensive range of factors. These factors include the safety record of the road, the road’s operating performance, the road and roadside infrastructure, geometry and roadside development. For Safe System, safety must be the dominant factor, with speed limits set to provide safety for the existing infrastructure and road users present.
This Guide is intended for road authorities to use when undertaking a speed limit review, considering a speed limit change or preparing and delivering a speed management policy through road infrastructure, vehicle technology, and behaviour change. The guide will also be valuable to road safety practitioners who are investigating speed limit changes as part of a solution to a road safety problem. Speed management is so fundamental to the Safe System approach that this Guide should be read in conjunction with all other Parts of the Austroads Guide to Road Safety.
Watch a recording of the webinar to learn more.
Edition 2.1 has been superseded. The latest edition is available here.
Edition 2.1 includes:
- Amended a statement in Section 3.3.
Superseded edition:
Edition 2.0 published November 2025
- 1. Introduction
- 1.1 Purpose of this Guide
- 1.2 Why is speed management important?
- 1.3 Speed and the Safe System
- 2. Speed and Harm
- 2.1 The relationship between impact speed and injury
- 2.1.1 Stopping distance
- 2.1.2 Energy transfer
- 2.1.3 Safe System speeds
- 2.1.4 Further insights on speed and injury severity
- 2.2 The relationships between travel speed, crash risk and injury risk
- 2.3 Brief notes on implementation issues from Safe System speeds and Vision Zero
- 2.1 The relationship between impact speed and injury
- 3. Co-Benefits of Speed Management for Other Critical Agenda
- 3.1 GHG and air pollution reductions from lower speeds
- 3.2 Active transport for health benefits and to Facilitate mass transit/public transport use
- 3.3 Reduced noise and its benefits (noting the extensive evidence for the substantial hidden health effects of noise on people)
- 3.4 Vehicle running cost reductions
- 3.5 Equity and social cohesion improvements
- 3.6 Net economic improvements from lower speeds
- 3.7 Speed management myths
- 3.7.1 People do not obey speed limits so there is no point in lowering them
- 3.7.2 Speeding is not a substantial cause of crashes
- 3.7.3 ‘I am a highly skilled driver, so I am safe to drive at high speeds’
- 3.7.4 Speed limits on roads in Australia and New Zealand are already lower than most good road safety countries, so we do not need them lowered
- 3.7.5 The problem is bad drivers, not high speed
- 3.7.6 Higher speeds are better for the economy
- 3.7.7 Higher speeds are a solution to congestion
- 4. Management and Leadership on Speed
- 4.1 Aligning structures and process in the management of speed
- 4.1.1 Speed information management
- 4.1 Aligning structures and process in the management of speed
- 5. Speed Behaviour on Roads
- 5.1 Range of speeds on the road network
- 5.2 Complications in perceiving speed risk
- 5.2.1 The psychology of risk misperception
- 6. The Case for Safe Speeds
- 6.1 Nilsson’s power model
- 6.2 Curves from in-depth crash investigations of speed
- 6.3 Evidence from Speed Limit Reductions
- 6.4 The case for addressing low level speeding
- 7. Ways to Manage Speed
- 7.1 Roads and roadside infrastructure
- 7.2 Vehicles
- 7.3 Speed limits and speed enforcement
- 7.3.1 The roles of local government
- 7.4 People
- 7.4.1 Personal factors
- 7.4.2 Legal factors
- 7.4.3 Situational factors
- 7.4.4 Social factors
- 7.4.5 Implementation intentions and pledges to counter speeding
- 7.4.6 People’s attitudes towards speeding
- 7.4.7 What does the community think about speed risks and speed management?
- 8. Types of Speed Limit
- 8.1 Default speed limits
- 8.2 Signed speed limits
- 9. How Do You Choose the Speed Limit?
- 9.1 Crash risk
- 9.2 Current operating performance
- 9.3 Road and roadside infrastructure, geometry and roadside development
- 9.4 Unsealed roads
- 10. Safe Speed for Regional and Remote Areas
- 10.1 Speed limits
- 10.2 Engineering treatments
- 10.3 Enforcing safe speeds
- 10.3.1 Covert and overt speed enforcement
- 10.4 Vehicle countermeasures – ISA
- 10.5 Speed management – community consultation and engagement
- References
- Appendix A Meaning of the 85th Percentile Speed
- A.1 Driver selection of safe (or optimum) speeds
- A.2 Speed dispersion