No New Zealand roads meet the top standard under a new safety rating system for state highways, although none are at the worst end of the scale either.

The KiwiRAP Star Ratings, developed by the AA and the Transport Agency, rate nearly 90 per cent of the state highway network, covering more than 10,000km of rural highways with speed limits of 80km/h or more.

The minimum length of highway assessed for a star rating was five kilometres.

"While New Zealand should aspire for our busiest roads to be at least four-star, our geography means that this can be difficult to achieve and will not be practical or affordable for all our state highways," said AA spokesman Mike Noon.

Thirty-nine per cent of sections were rated two star, 56 per cent were three star, and 5 per cent were four star, with five stars the best rating.

The ratings would not be signposted along roads, as sections could change in safety rating over short distances. The ratings were instead intended to improve awareness about the risks.

"If we can increase public awareness that different parts of the state highway network have different levels of safety, drivers will have a better understanding of how roadside hazards like trees, ditches, poles and narrow shoulders can increase risk," Mr Noon said.

As well as influencing driver behaviour, the programme was also intended to help improve road engineering.

Sections of road were also assessed according to collective and personal risk.

The section of road with the highest collective risk was State Highway 2 between Napier and Hastings, followed by SH2 from Mount Maunganui to Paengaroa, and SH2 from Bay View to Napier.

The sections with the highest personal risk were SH62 from Spring Creek to Renwick, in Marlborough, SH37 to Waitomo Caves in the King Country, and SH94 from Te Anau to Milford in Fiordland.

Personal risk measured the danger to people using the road, and accounted for traffic volumes, while collective risk was the number of fatal and serious injury crashes per kilometre over the road.

KiwiRap was part of an international programme of road assessment.

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