Number of 'dangerous' Rotorua potholes rising

Between 2016 and 2020, 1055 potholes were repaired in the section of SH30 that includes Te Ngae Rd. Photo / Ben Fraser, File

The number of potentially "dangerous" potholes in Rotorua is on the rise and drivers can be left paying hundreds in repair costs.

Data obtained by the Rotorua Daily Post reveals the number of potholes being repaired on Rotorua Lakes Council roads increased from 741 in 2016 to 1021 in 2020.

And rural areas have been most affected by the rise with 239 potholes repaired on rural roads in 2016 and 415 in 2020.

In total, 4317 potholes were repaired on Rotorua Lakes Council roads in the five-year period

Rotorua Rural Community Board chairwoman Shirley Trumper said there were many reasons for more rural potholes. In her view, these included material quality and road construction standards being lower than in Australia.

There were also a large number of unsealed rural roads which could lead to more potholes, she said.

"The transport team at the council do the best they can with what they have."

In the same five-year period Waka Kotahi New Zealand Transport Agency repaired 12,760 potholes in the Eastern Bay.

The data revealed State Highway 30 was the most prone local highway for potholes.

Between 2016 and 2020 a total of 3343 potholes on SH30 were repaired. This included 1055 potholes repaired on the Sala St and Te Ngae Rd section of the highway.

Council infrastructure and environment deputy chief executive Stavros Michael said the organisation considered any undulation of the road surface as a pothole.

"This means it could be as little as 25mm (loss of surface chip) or as deep as 100mm, which is what most people would classify as a typical pothole."

Michael said general causes for potholes included weather such as extreme rainfall, icy temperature or residential construction works.

"We are seeing weather events happening more frequently and more intensely and we can say for sure that water ingress inside the road pavement is causing 80 per cent of road surface damage."

He said the council's average reseal programme had stayed steady at about 70kms per year "so there is no direct apparent reason for pothole number variances".

In response to Trumper's comments, Michael said New Zealand's national roading standards were no different to most of the world's developed countries. Also, while the structure of roads was generally consistent there could be differences in some areas due to traffic volumes and demand.

Waka Kotahi regional manager maintenance and operations Rob Campbell said water did to roads what sugar did to teeth.

"When water penetrates the road surface through cracks, tyre action and weather can quickly turn these cracks into potholes."

Higher traffic volumes, numbers of heavy vehicles and levels of rainfall or groundwater made roads more pothole prone.

"SH30 in Rotorua see tens of thousands of vehicle movements each day, particularly on Te Ngae Rd, as one of the busiest routes into and out of Rotorua."

Waka Kotahi regional manager maintenance and operations Rob Campbell. Photo / George Novak

Campbell said detours caused by roadworks could sometimes increase traffic on roads with pre-existing issues and this could cause potholes to form.

Asked what the cost of such repairs was, Campbell said this information was not available as they did not track individual activity costs. Generally, repairs were covered by ongoing contracts with road maintenance providers.

Carter's Tyre Service Rotorua owner Mark Fisher said he and his team looked after five or six pothole-damaged cars each week.

"People are making comments all the time about them," Fisher said.

"Sometimes the alloy rim of a wheel will crack and you don't know the tyre is slowly leaking air."

AA Motoring advisor Cade Wilson said potholes could pop tyres and driving over potholes repeatedly could result in worn out suspension links or shock absorbers.

"Potholes can be dangerous," Wilson said.

"If a tyre is popped at speed and the vehicle becomes unstable the driver could get a fright and react.

"It can also be dangerous if a driver sees a pothole at the last minute and swerves to avoid it."

Wilson estimated tyre and wheel repairs for a general vehicle could cost between $100 and $300.

An early 2020 survey of AA members in the Bay of Plenty found that 37 per cent rated the roads in their area as very poor or sub-standard.

The same survey found "Road surface quality (potholes)" to be the greatest road maintenance concern for AA members across the country.