All over the world, including New Zealand, examples show that when mean travel speeds reduce, fatalities and serious injuries decline. Conversely, when speeds increase, more people die. The formula is clear and has been repeatedly proven.

The Ministry of Transport reported that in 2021, road crashes in New Zealand had a social cost of over $9.7 billion. The costs on the economy and ordinary New Zealanders are staggering. The personal costs on police and other emergency service workers who attend these crashes can be life-changing and traumatic. Governments must take steps to reduce the trauma by applying the “evidence” and not insupportable political whim.

Reversing life-changing speed-reduction measures and the planned approach to reversing speed limit reductions will not “boost productivity and economic growth” as claimed. It will increase the numbers killed and seriously injured.

The Australasian College of Road Safety, referencing the current Government’s approach to speed, said it was “stepping back 20 years”. The college is right.

New Zealand’s death rate was reported at 7.3 per 100,000 of population by the OECD in 2022. This is over 300% higher than the world’s best-performing countries such as Sweden and Switzerland, which implemented, among other initiatives, survivable speed limits that are based on “safe system” principles.

One of the key obstacles to reducing New Zealand’s appalling road safety performance is setting “survivable” speed limits. A default 100km/h speed limit on non-median divided rural roads where head-on and run-off-road collisions can occur is a critical problem. Where speed limits have been lowered to survivable limits of 80 km/h, such as on the Napier-Taupo Road or from Blenheim to Nelson, the lifesaving benefits have immediately come.

Police has a powerful opportunity to strongly advocate for evidence-based speed limits that will save lives and reduce the enormous burden that preventable road trauma represents.

Speed limit reduction impacts

When the speed limit was reduced in Sweden from 90km/h to 80km/h on a large portion (21%) of the state road network (mainly undivided rural roads), the mean speed was found to have reduced by more than 3km/h and the number of fatalities was reduced by about 40%.

In a bigger sample size, in France, where speed limits on similarly undivided rural roads were reduced in 2018 from 90km/h to 80km/h, fatalities were reduced by 12% on the relevant part of the network, with an overall reduction of 331 deaths on an annual basis compared with the previous four years.

At home, during the 1973 fuel crisis, the New Zealand Government reduced rural speed limits from 55mph (89km/h) to 50mph (80km/h). Due to concern over fuel shortages, many people complied with the new speed limit – there was an 8-10km/h reduction in average rural speeds. The drop in speeds led to a significant drop in injuries compared with roads unaffected by the speed limit change (urban roads).

Conversely, in 1987-1988, 40 American states raised the speed limit on interstate highways from 55mph to 65mph (89km/h to 105km/h). Speeds increased by 5km/h on average and deaths increased by between 20% and 25%.