It's been a summer of change for drivers, with some state highways across Aotearoa having had their speed limit recently reduced.

It's all part of the New Zealand Transport Agency - Waka Kotahi's Road to Zero vision - the aspiration that no-one is killed or seriously injured in road crashes.

There's the 30 kilometre long chunk of State Highway 2 between Katikati and Tauranga, where speed limits are now set at either 60 or 80 km/h.

One of the changes affects a section of State Highway 1, just 190 metres long, in South Canterbury's Winchester. The speed limit used to be 100km/h, but has now been halved.

But by far the longest and most substantial change to have been made by Waka Kotahi is the 110 kilometre long State Highway 6, between Blenheim and Nelson.

There, speed limits now never reach 100, and alternate mostly between 90 or 80km/h.

But the changes haven't gone unnoticed by locals.

"When's 90 been a speed limit?" asked Seddon resident Moana Johnsen.

"We've got decent vehicles, that stick to the roads, and we've got to do 90? 90 in an open space?

"And then there's 80 and then there's 60 going up a hill that's got an overtaking space? Yeah nah, it's revenue gathering, mate, revenue gathering."

Moana made the State Highway 6 journey four times over Christmas - and each time, was frustrated at the new limits.

"Christmas Day we must have spent quite a bit on it, and you know, the young people that were there, the 20s, 30s year-olds, they were like, 'This is not fair'... they've all got nice cars and stuff."

She says she was worried about the overall trend.

"They've done all these changes further down the road, the Kaikōura coast, which has been fixed up and made really nice.

"But they've got signs up there too: 60, 80. Is the open road going to go to 80?

"It's ridiculous, might as well get my horse and cart out and trot up and down the road. If our roads are not up to 100km/h, then fix them."

But Waka Kotahi says making sure speeds were safe was the quickest and most effective way to prevent deaths and serious injuries.

In a statement, an agency spokesperson says safe speed limits minimised the severity of crashes when they occurred.

"[The] Agency is currently identifying roads where reviewing speed limits could make a big difference in preventing deaths and serious injuries, and where communities are calling for change.

"Any proposal to drop speed limits is driven by the need to improve safety and reduce harm for everyone on our roads."

But road safety charity Brake NZ director Caroline Perry says many more roads needed to be looked at - and not just state highways.

"We still see at the moment a significant proportion of roads in New Zealand that have speed limits that don't match the condition of the roads.

"A lot of the more rural roads that are windy, narrow, single or dual lane, they're just too fast for the conditions of the road that we have at the moment."

She did think that was changing - and speeds were coming down, but not fast enough.

-RNZ