Read more: Speed limits 'unsafe' on nearly all NZ roads, says NZTA planning guide
"Originally the guide was aiming to target 5 per cent of the roading network with the highest safety benefits, then that was increased to 10 per cent," said Mike Noon, AA's motoring affairs general manager.
"Now some areas are looking to change speed limits on the majority of their roads while others are picking out a few bits and pieces.
"Some are using the guide's recommendations unchanged while other places have adjusted them, so it's inconsistent," Noon told the Herald.
He also suggested some councils, such as Napier and Hastings, might be taking the easier option of reducing speeds rather than upgrading roads to make them safer.
"We have seen little of this coming through in proposals so far and we are concerned that we are going to just see limits coming down across the country."
Check the interactive graphic below to see fatal and serious crashes on NZ roads since 2000 and how current speed limits compare to the safe and appropriate speeds suggested by Mega Maps.
Road deaths since 2000
Each red dot on the map shows one fatal road crash. Zoom in to explore.
Serious injuries in road crashes since 2000
Each purple dot on the map shows one serious road injury crash. Zoom in to explore.
100km/h speed limit
NZTA's Mega Maps planning tool estimates 95 per cent of NZ's open road should have a lower speed limit than 100km/h. Drag the slider from left to right to see how many roads are affected.
Explore the interactive map
Noon also questioned whether the road-using public were being sufficiently consulted on proposed changes.
"Whether a change to the speed limit makes sense to people or is supported by the public seems to not really matter under the guide, which questions the point of having consultations on these issues at all if the outcome is already determined," he said.
The AA has written to Genter seeking a review of the guide.
Reckless drivers the biggest fear in Hawke's Bay
Ten people have died on the roads in Gisborne-Hawkes Bay this year. Five of them were killed on state highways, four on local open roads and one on an urban road.
According to NZTA research carried out in 2017 on New Zealanders' attitudes to road safety, risk and safety solutions, New Zealanders cared about road safety but believed that deaths were unavoidable.
Understanding of road risks varied, leading to uncertainty about the most effective solutions. Most people believed community conversations would lead to improved safety yet few agreed the right road risks were being talked about.
According to the research, people in Gisborne-Hawkes Bay are similar to the national average when it comes to conversations about road risk. They identify similar road risks and hold similar views about the effectiveness of safety solutions.
Some 39 per cent of people believed reducing speed was effective to improve road safety while 60 per cent thought improved enforcement was also effective.
Just over 40 per cent of people could identify a local road risk but around 30 per cent said they could not. Careless or reckless driving was the top perceived road risk, following by travelling fast.
Hastings City Council made speed limit changes in 2018.
Napier City Council is reviewing speed limits at present.
Communities must be consulted
The New Zealand Transport Agency, which developed the guide and administers Mega Maps, said that when carrying out public engagement on proposed speed limit changes, it and other RCAs provided a range of information including the 'safe and appropriate speed' calculated for the road being consulted on.
"When reviewing and setting speed limits, councils and the NZTA need to bring communities along with us by having open and honest discussions about speed, listening to people and understanding different perspectives, so that when a decision is made to change a speed limit people understand why the change is being made," said Niclas Johansson, NZTA's acting director of safety and environment.
The NZTA, as a road controlling authority, also seeks public input when reviewing speed limits on state highways, for which it has responsibility.
"As well as the technical inputs on what is a safe and appropriate speed for a state highway, we also engage with communities at an early stage to better understand how people use the road and what other factors might ultimately influence safe speeds and speed limits," Johansson said.
"Communities typically tell us that increased traffic volumes, new developments such as a shopping centre or sub-division, a new school, increased number of tourists, or a greater number of cyclists are all factors that influence their views on safe speeds."
Johansson said that in many cases, speed reviews were initiated because of community feedback or concern.
Genter said she also received a lot of correspondence from communities and local authorities that wanted safer and more appropriate speeds in their area.
"Up until now it's actually been difficult for them to implement the speed limit they want," she said.