Waka Kotahi is reviewing speed limits as part of the national Road to Zero strategy. Photo / Supplied
Waka Kotahi is reviewing speed limits as part of the national Road to Zero strategy. Photo / Supplied
Estimated travel times for professional road users like truck drivers could increase by up to 20 minutes on a trip between Auckland and Wellington if lower speed limits are introduced.
A Herald analysis has indicated that, if implemented, the reductions proposed by the Government’s transport agency Waka Kotahi would alsoadd about 28 minutes to the roughly nine-hour journey between Picton and Dunedin.
The proposed changes for the 62km route from SH1 to Tauranga via SH29 were estimated to add between 13 seconds and three and a half minutes to the trip.
The estimated travel times under the proposed lower speed limits - which have not previously been revealed by officials or the Government - have prompted a mixed reaction from transport commentators.
The Trucking Association supported speed reductions if it would make roads safer but National’s transport spokesperson Simeon Brown said the Government was taking the “easy option” by reducing speed limits rather than looking at the wide-ranging issues of road safety.
“Ultimately, New Zealanders are crying out for better roads, not slower roads.”
Herald analysis: Travel time impacts
The Herald analysed Waka Kotahi data for three key routes in New Zealand to estimate the impact speed limit proposals and reviews could have on travel times for professional drivers and other long-distance road users.
The three routes were: Auckland to Wellington; SH1 to Tauranga via SH29; and SH1 from Picton to Dunedin.
Between Auckland and Wellington, 284km of the 642km of road has been identified as having a safe and appropriate speed of 80km per hour, according to Waka Kotahi’s Road to Zero speed analysis system.
Using Waka Kotahi’s travel time analysis, the New Zealand Herald estimated changing the speed limit from 100km/h to 80km/h on all 284km of road would add about 20 minutes to the roughly eight-hour journey
This 20-minute increase in travel time comes from Waka Kotahi’s automated analysis of what it thinks the mean operating speed - how fast motorists actually drive - will be after the speed limit changes are applied. In some cases, the agency expects the new mean operating speed to be higher than the new speed limit.
When the Herald repeated the calculation with a maximum mean operating speed of the proposed speed limit (80km/h), the increase in travel time between Auckland and Wellington is about 30 minutes.
However, for truck drivers, who are already driving slower than other road users in 100km zones, the impact could be as low as 13 minutes and up to about 20 minutes.
Newly opened roads between Auckland and Wellington are likely to further reduce the increase in travel time.
SH1 to Tauranga via SH29: At most, 3 more minutes
For the roughly one-hour journey from SH1 to Tauranga, via SH29, the Herald analysed data from Waka Kotahi’s Interim State Highway Speed Management Plan 2023-2024.
Based on a proposed reduction to 90km/h on about half of the route, the Herald’s analysis estimated the travel time change would be about 13 seconds.
However, Waka Kotahi’s analysis showed about 75 per cent of this road has a “safe and appropriate speed” of 80km/h.
When the Herald repeated the analysis with 80km/h as the limit, the travel time change was between 3 and 3.5 mins for cars and 2.5 to 3 mins for trucks.
Between Picton and Dunedin, 385km of the 692km journey has been marked by Waka Kotahi as having a safe and appropriate speed of 80km per hour.
If the speed limit was reduced to 80km where applicable, the estimated increase in travel time would add around 28 minutes to the 9-hour journey for regular road users.
For trucks, it is estimated to add between 17 and 32 minutes to the journey.
Trucking industry: Slower speeds reduce travel time but safety most important
David Boyce, chief executive of the New Zealand Trucking Association, said he supported speed limit reductions if it was going to make the road safer.
He said some roads were “challenging” to drive at times and required infrastructure improvements and maintenance.
“Safety is the most important consideration, and ... the speed limit should be appropriate for the conditions.
“Slower speeds do reduce travel times but the most important thing from my point of view is the speed matches the conditions; does it match the road surface or design and does it match the traffic volume?
“You can lower a speed, and yes it might slow the average speed down, but it doesn’t necessarily reduce the travel time.”
A big issue, he said, was driver behaviour around trucks. Many road users did not understand how to drive around trucks.
“They do things like slam their brakes on in front of them when they haven’t got enough clear room to stop for the trucks, they go into blind zones.”
Don Braid, group managing director of Mainfreight, said because speed limits for heavy vehicles were below the posted speed limit, he didn’t expect speed limit reductions to have a noticeable effect on the movement of freight around the country.
“Improving the road and rail infrastructure across New Zealand would improve the safety of our roads a lot more than speed restrictions. The new Auckland Hamilton/Cambridge expressway [is] a good example.”
National’s Simeon Brown said an increase in travel time could have significant impacts on freight, including companies requiring more drivers or trucks to cover the same routes.
National's Simeon Brown says more needs to be done to improve roads rather than reducing speed limits. Photo / Angus Dreaver
He said the Government needed to do robust economic and cost analysis of the speed limit reductions on travel times.
National was supportive of the plans to reduce speed limits around schools, he said.
Like Brown, Transporting NZ’s chief executive Nick Leggett said Waka Kotahi’s proposed speed limit changes would slow New Zealanders and the economy down and the transport agency needed to focus more attention on fixing roads and installing safety infrastructure.
Waka Kotahi rejected this, saying it is investing in roading infrastructure at pace and the coming summer season of road renewals, which includes resurfacing or rebuilding roads, will be the largest in New Zealand’s history.
Waka Kotahi’s portfolio manager Road to Zero Tara Macmillan said $617 million would be spent this season on state highway maintenance and $1.5 billion on local roads.
“Road to Zero is not about focusing on one treatment over another. It’s not speed over other things.
“We are invested in infrastructure, we see the importance of infrastructure, and we are rolling out at pace infrastructure improvements across the country.”
The infrastructure improvements were not things Waka Kotahi “could do overnight” and speed reductions were generally quicker and less costly.
AA’s road safety spokesperson Dylan Thomsen said New Zealand had not been investing enough in roads but it was an issue that has existed for at least 10 years and preceded the current Government.
“I think Waka Kotahi has a bit of an impossible task in that area at the moment. They don’t have the funding level they need from the Government.
“It’s not going to be a quick fix; it’s going to take some years of sustained work to turn things around.
