Drivers have claimed a new safety system installed along the A9 has actually made the road more dangerous.
Average speed cameras have been put in place at a number of sites between Perth and Inverness as part of a £2.5 million project.
Although the system is still being tested ahead of going live in October, motorists have reported a significant change in driver behaviour.
One campaigner revealed average speeds in camera zones were as low as 32mph, describing it as “a complete farce”.
David Thomson said: “Lorry drivers are now sitting at less than 40mph because of the cameras, causing complete chaos.
“Whenever there is a gap, motorists are taking ever more chances than before. I dread to think what it will be like once all the cameras are installed.”
Meanwhile, other drivers have reported queues of between 40 and 50 vehicles, as well as an increase in dangerous overtaking manoeuvres.
The founder of the A9 Average Speed Cameras Are Not The Answer campaign, Mike Burns, called for a public inquiry into the project.
“Drivers are now reporting a rise in observed risky overtaking manoeuvres, an average speed which is so low as to render the A9 a no-go zone for many drivers,” he said.
“This will cause a significant impact on the Highland economy.
“Transport Scotland and the A9 Safety Group must be subject to a public inquiry on this fiasco and for adopting a scheme which could be construed as negligent by creating conditions which are creating worse driver behaviour.”
A Transport Scotland spokesperson said: “The A9 Safety Group is clear that average speed cameras are effective in saving lives. Claims that speed is not an issue on the A9 have no foundation in fact.
“Of the offences recorded by Police Scotland and the Safety Camera partnerships last year, more than 95% were speed related.
“The comments in terms of the role speed plays in accidents have been misrepresented.
“It is unfortunate the campaign group has rejected the recent meeting offered to them by the chairman of the A9 Safety Group.
“This would have allowed us to address the lack of understanding of the work that is being carried out and explain the role the cameras have in supporting safety on the A9.”