Truckers across the UK are campaigning for an increase in speed limits for large heavy goods vehicles (HGVs) from 40mph to 50mph, saying such a rise would actually improve safety.
In protest, they are vowing to stick to the current 40mph limit for the rest of the week, meaning traffic is bound to face tailbacks, with Christmas deliveries possibly being affected.
However, the organiser of the protest, Inverness-based HGV driver Conor McKenna, said lorry drivers would pull over and let traffic pass when they could.
So far, more than 6500 HGV drivers have pledged to join in the protest.
While raising the limit would mean earlier delivery times, drivers say the main motivation is road safety. The current limit restricts vehicles above 7.5 tonnes to 40mph, which is 20mph slower than cars on A-class single carriageway roads.
Hauliers say it leads to dangerous overtaking by frustrated motorists.
Mr McKenna, 28, who drives for DPS Haulage in Dingwall, wants a change in the law.
Before setting off along the A96 from Inverness to Aberdeen yesterday, he said: "A lot of the public don't seem to know that we are restricted to 40mph. Drivers have been looking for the change for years and years and they have been contacting me from right across the country.
"We all drive cars as well as lorries and are well aware of how frustration can build up in a tailback behind an HGV doing 40mph on the A9. That's when people take risks. But if a lorry is sitting at 50mph, the traffic will be flowing better, there will be less congestion and less frustration. It would be safer."
He said the HGVs' braking systems had also improved significantly since the 40mph limit was imposed.
The UK Government has started consulting on a proposal to raise the speed limit for larger lorries to 45mph or 50mph on single carriageway roads.
However, the Scottish Government now has powers to raise the limit north of the Border and ministers are considering a request for a pilot scheme on the A9. A Transport Scotland spokesman said: "While we currently have no plans to implement an increase in speed limits across Scotland's roads, members of the A9 Safety Group have called for consideration of a trial of increased speed limits for HGVs on this particular route. Further information will be made available in the new year."
Highlands and Islands Labour MSP David Stewart believes the change should be made not least because he regularly drove on the A9 and witnessed "some crazy overtaking, much of the time by vehicles travelling behind lorries".
"It is ridiculous to keep a 40mph limit," he said. "These drivers cover huge distances every year and are very professional and experienced."
The road safety charity Brake said there was clear evidence of a direct link between traffic speed and road accidents. Its website warns that more than half of all UK fatal crashes occur on rural roads.
For HGVs over 7.5 tonnes the national speed limit is 40mph on single carriageway roads, 50mph on dual carriageways and 60 mph on motorways. For goods vehicles under 7.5 tonnes the national speed limit is 50 mph on single carriageways, 60mph on dual carriageways and 70mph on motorways.