"If there is one message that needs to be heard it is to stop blaming the roads and the speed limits and start taking driver responsibility, training and testing seriously," he said.
"The best investment we can ever make in saving lives and reducing the road toll is by putting more resources into training people how to be safer drivers."
He said specific practical training for motorists would create much better driving awareness and ensure drivers are focused and less distracted.
"As a parent I know, the driver licensing system in New Zealand is broken," Murphy said.
"I see my son getting six months knocked off his restricted licence just by doing a Defensive Driving course where he's sitting in a classroom for eight hours."
"Is that actually going to make him a better driver at his most critical time of learning – I don't think so."
Transport Minister Phil Twyford, meanwhile, said the Government would look at the NZTA work as part of a larger transport safety strategy.
Police Minister Stuart Nash said this work needed to include a look at what speeds were right for each individual road, rather than a blanket reduction on speeds.
"What we're doing is looking at how we lower the road toll, at the minute we have a road toll that is totally unacceptable, too many people are dying, and we do recognise that speed it a major factor," Nash told Newstalk ZB's Mike Hosking.
"What I will say is we are not looking at carte blanche drop of the speed limit to 80km/h on every single road."
"Some of our state highways are actually engineered for a speed of 80km/h and some others around south of Auckland ... are engineered for 120km/h."
The comments come after the Herald published data maps showing the vast majority of speed limits on New Zealand roads are too high for the conditions.
The NZTA's Mega Maps online risk assessment tool - which is used by the NZTA and councils as a guide for deciding on new speed limits - suggests only 5 per cent of the open road should have the current 100km/h signposted speed limit.
Mega Maps suggests a safe and appropriate speed of between 60km/h and 80 km/h should instead apply to most stretches of open road.
Racing legend Murphy said there was a need to improve Kiwi roads.
"Improving the country's roading network will improve transport efficiency and in some cases it might assist in reducing injuries and deaths, but people will still crash if we don't change the current driving culture," he said.
"Nothing will change, unless we go to the root the problem which is how people are driving, how we are training them, how we are testing them.
"When we have better, safer drivers, then New Zealand's road toll will go down."
Road Transport Forum chief executive Nick Leggett has also earlier said a blanket reduction on speed limits would "slow our economy down".
"They're Mega Maps of what have been, not what is," he told NewstalkZB. "And they don't actually suggest a solution, someone is putting a solution on top of that and saying, 'well actually it fits nicely into the ideological drive of the Government', which is anti-roads, sadly.
"Roads are relied upon by millions of Kiwis to go about their daily business, for us as an industry to get goods to market because we're an export-driven economy. Slow that down, you slow the New Zealand economy down."
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.
50km/h speed limit
Mega Maps also estimates many urban roads should have speed limits lower than 50km/h. Drag the slider across to see how almost two thirds of Auckland roads are affected.
Explore the interactive map
