The speed limits on nearly 90 percent of New Zealand roads are too high, according to a NZ Transport Agency (NZTA) tool.
Mega Maps is an interactive risk assessment tool used by the NZTA and councils to help decide the appropriate speed limit for roads.
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It uses a range of factors to assess the road, including the road width, crash history, potential hazards, and volume of traffic.
According to the tool, 87 percent of speed limits across New Zealand are too high and only five percent of open roads should have their current 100km/h speed limit.
Instead, the tool finds a more appropriate speed of between 60 and 80km/h should apply on open roads, while in some urban centres, Mega Maps suggests speed limits between 30 and 40km/h.
In Auckland, 65 percent of 50km/h streets would require a lower speed limit.
In May, Associate Transport Minister Julie Anne Genter said too many people were dying on Kiwi roads and rolling out more appropriate speed limits was identified as a way of reducing those numbers. She did, however, rule out a blanket reduction.
"What is important is that we're going to focus on the most dangerous roads, revising them to have a safe and appropriate speed limit, and making it easier for local councils to get a safe and appropriate speed limit," she told RNZ at the time.
National Transport spokesperson Paul Goldsmith said on Wednesday that a "wholesale reduction" should be avoided as it would weaken the economy by making it longer for businesses to move freight.
"Over the past three years the road toll has risen, and we should absolutely be focused on understanding why. But it’s worth remembering that speed alone is not the cause.
"Other factors include drugged-driving, enforcement of current laws around drink-driving, not wearing seat belts, the quality of our roads, driver distraction and a huge increase in tourism."
In December, the Government announced it would spend $1.4 billion on road safety improvements. The three-year programme would aim to make 870km of high-volume, high-risk state highways safer by 2021.
This could involve installing new median and side barriers, rumble strips and shoulder widening.
Auckland Transport (AT) has previously considered lowering speed limits. In November, chief executive Shane Ellison said the city needed "survivable speeds" which are speeds at which a pedestrian could likely survive a direct impact crash.
In February, AT said there were plans for roads like Hobson St, Customs St and Nelson St to be reduced to 30km/h.
The International Transport Forum has recommended that in order to reduce the risk of head-on collisions, rural roads without a median barrier should have a speed limit of 70km/h and 30km/h in city areas that have vulnerable road users like cyclists.