The introduction of average speed cameras on the busy A90 between Stonehaven and Dundee has led to “significant improvement” in driver behaviour.
Speed surveys indicate that 99 out of 100 vehicles are complying with the speed limit since the cameras became operational on October 31 last year.
Before the installation on the 50-mile route, three out of every five vehicles were speeding.
Evidence has also shown that only one in every 5000 vehicles is now speeding at more than 10mph over the limit.
This compares to one in five before the introduction.
Transport minister Humza Yousaf said: “These findings add to the compelling evidence that average speed cameras help to transform driver behaviour.
“I’m confident that this encouraging improvement in speed limit compliance along the length of the A90 will help to reduce casualties in the same way as has been achieved with similar average speed cameras on the A77 and A9.”
Chief Inspector Stewart Mackie, area commander for road policing north, said: “I am delighted that the initial results from this project has had such a dramatic effect on driver behaviour, which is what they were intended to do.
“Reducing excessive speed on this road directly corresponds with reducing the chances of people being injured and killed in road traffic collisions.”
The speed surveys were carried out last month at a series of locations north and southbound.
Stonehaven and District Community Council also welcomed the findings.
It said: “It is encouraging to see a significant improvement in speed limit compliance.
“The A90 is a vital route for our community and we are hopeful that the average speed system will keep those who live, work and travel to Stonehaven, safer on the road.”
The community council recently held a poll on its Facebook page asking people if they felt the introduction of the average speed cameras on the A90 had reduced speed and improved driving conditions.