A panel of road safety experts has criticised local and international moves to increase speed limits, saying they would only ensure more people would die.

Former police commissioner for road safety Dave Cliff, researcher Hamish Mackie, and Auckland Transport safety technical lead Ping Sim faced media on Thursday morning, airing their concerns.

“The benefits of speed reduction are enormous. Equal speeds equal lower trauma rates, lower social cost and enormous cost savings to the community,” Cliff said.

The total social cost of motor vehicle fatal and injury crashes in 2020 was estimated at about $4.4 billion, according to the Ministry of Transport.

Social costs comprise a range of factors including; loss of life or quality of life, loss of earnings potential due to death, permanent injury or temporary disability, emergency, hospital and rehabilitation costs, legal and court costs and vehicle damage.

“You often hear a desire to increase speed limits, that going faster will be better for the economy, or that people don’t want longer travel times,” Cliff said.

“Any call for increased speed limits, directly means they’re asking for more people to be killed or seriously injured in road crashes, push up costs, and push up people going into the hospital system at enormous costs,” Cliff said.

This comes as National says it will undo Labour’s blanket speed reductions, returning many State Highways to 100kph after they were lowered to 80kph.

Transport Minister Simeon Brown said in September that National would repeal and replace the rules that set speed limits so that economic impacts – including travel times – and the views of road users and local communities counted, alongside safety.

“We anticipate this resulting in highways going back to 100kph speed limits, except where it would be unsafe to do so. Similarly, we’ll restore local roads to 50kph from 30, except where that would be unsafe,” Brown said.

The trio argued that locations with possible conflicts between pedestrians/cyclists and cars, such as standard local roads, should remain at 30kph, intersections with possible side impacts between cars should be 50kph, roads with possible frontal impacts between cars, such as rural roads, should be 70kph, and roads with no possibility of a side or frontal impact, like motorways, should be 100kph.

This was to ensure that if an accident were to occur, rates of survivability would remain high, based on local and international research, they said.

In terms of fears that lowering speed limits would create longer, and more frustrating, trips, Sim said the delay would be less than 15 seconds.

“Predictions across a range of scenarios that the expected travel time delay of the proposed changes is less than 15 seconds for an average urban Auckland trip which is about 20 minutes,” she said.

“It’s largely because if you think particularly about the urban driving experience and where you actually end up losing time, you end up stopping at lights, and that takes a lot of time. Or a car in front of you slows down or decides to turn left.

“So there’s not actually a lot of time, particularly during rush hour or congested time, where you might be travelling at a free flow speed.”