Safe speeds - the reasons Safe speeds - the reasons

One of AT’s key priorities is keeping Aucklanders safe as we walk, cycle, bus, train, ferry, and drive. Our Vision Zero goal is to have no one die or be seriously injured on our roads by 2050. We have committed to this goal because we believe that no one should die or be seriously injured for simply getting around Tāmaki Makaurau Auckland. Safe and appropriate speeds are travel speeds that are appropriate for the function, design, safety and use of the road.

The case for safe speed limits

The evidence is clear, safe speed limits save lives.

We know that where safe and appropriate speed limits have been implemented injuries and deaths have reduced. Data from the first phase of speed limit changes in June 2020, shows 30 percent reduction in deaths and 21 percent reductions in serious injuries. In comparison, across all Auckland roads for the time period (24 months), road deaths increased by 9 percent.

Setting safe and appropriate speeds is an effective tool to save lives and prevent debilitating injuries. It could also save the life of someone you know and care about.

Read the full report: Safe Speeds Phase 1, 24 Month Interim Evaluation (PDF 789KB).

Risk of death vs impact speed

Infographic showing death and injury risk percentages. The death percentage risk increases from 10% to 80% when speed increases from 30km/h to 50km/h.

Image: Death and injury risk percentages

The impact of speed on the human body

Setting safe speed limits, to what a human body can survive, is important because two out of three serious injuries are happening to people outside of vehicles. The internationally accepted speed to greatly reduce the chances of a pedestrian being killed or seriously injured is 30km/h.

For people who are walking or biking, a reduction in vehicle speed from 50km/h to 30km/h translates to a 90% chance of surviving the crash. Setting safe speed limits where people walking and cycling mix with vehicles, like in town centres and around schools is essential to reducing death and serious injury (DSI).

Safe speed limits save lives

Speed makes a major difference in a crash. It affects a driver’s ability to react and stop in time. Regardless of the cause of a crash, speed is the difference between someone being unharmed or being seriously injured or killed. 

Making our roads safer

Aotearoa, New Zealand’s road safety performance is significantly worse than that of the world’s best-performing countries. Countries similar to Aotearoa in terms of geography, population and culture have embedded Vision Zero and Safe System principles into their road safety strategies, drastically reducing the number of road deaths and serious injuries.

Graph showing road fatalities per billion kilometres travelled. The graph shows that New Zealand has a fatality rate of 8 and this is higher than most other countries in the graph

Image: Graph showing road fatalities per billion vehicle kilometres travelled

As speed increases, so does the likelihood of serious injury or death because of the following reasons:

  • the driver has less time to react to a hazard
  • the distance travelled before coming to a stop is greater
  • the speed upon impact is greater


Lower driving speeds also benefit quality of life, especially in urban areas as the reduction of speed mitigates air pollution, greenhouse gas emissions, fuel consumption and noise.

This perception of safety is key to unlocking a lot of positive behaviours. When people ‘feel’ safe, they tend to do things that they enjoy – walk or cycle more which automatically has positive health benefits for people and for our planet, with lowered carbon emissions. Overall, it leads to better wellbeing living in neighbourhoods that are quieter, safe and have cleaner air.

Congestion and travel times

Contrary to thinking that driving at safe speeds will take more time, it can be the opposite. Research shows that travelling at a safe speed does not add very much to travel times. For example, going 5km/h over in a 60km/h zone on an average commute saves you just 75 seconds but doubles your crash risk.

The social cost

On top of leaving a huge hole in the lives of families, friends, workplaces and communities, road crashes have a huge impact on our society.

The value of statistical life (VOSL) was estimated at $4.42 million per fatality at June 2020 prices. Adding other social costs (medical care, legal and court, vehicle damage) gives an updated average social cost of $4.46 million per fatality. There are significant social cost  resulting from fatalities where speed has likely been a contributing factor.

There’s a lot of misconceptions about speed changes, you can learn more about myths and misconceptions about the speed limit bylaw on the OurAuckland website.

To learn more, see Safe Speeds FAQs.

Equity in road harm in Auckland

This research explores equity in road harm in Auckland considering age, ethnicity, mode of travel and deprivation. The analysis looks at data from the Waka Kotahi Crash Analysis System, Stats NZ population data, and the Ministry of Transport Household Travel Survey.

Download the full report: Equity in road harm in Auckland 2022 (PDF 5.05MB).