VAN and lorry drivers show the "least compliance" with Scotland's speed limits, an unpublished Transport Scotland study shows.

The research tracked the speeds of around 11 million vehicles on single and dual carriageways and found those driving HGVs (heavy goods vehicles) were the worst offenders.

Police chiefs argued that part of the problem could be people hiring vans and being ignorant of the limits on the roads.

Calls have since been made by road safety groups to improve awareness for professional drivers and those renting the vehicles.

Minutes of a Transport Scotland road safety group meeting which discussed the report stated: “The main finding was that HGVs [heavy goods vehicles – over 3.5 tonnes]/large vans showed the least compliance, making this an enforcement issue.”

Superintendent Louise Blakelock, Police Scotland’s deputy head of road policing, told the meeting it was working with hire firms to better educate drivers on the different speed limits.

Vans under two tonnes have the same speed limits as cars; however, larger vans and lorries up to 7.5 tonnes are limited to 50mph on single carriageways, 60mph on dual carriageways and 70mph on motorways.

In Scotland, lorries over 7.5 tonnes are limited to 40mph on single carriageways apart from the A9, 50mph on dual carriageways and 60mph on motorways.

Neil Greig, of the IAM RoadSmart motoring group, said speed camera officials “frequently report ignorance of van speed limits as one of the most common excuses they get from drivers”.

He added: “Ignorance by professional drivers is not acceptable, but if they are just thrown the keys of a transit having only ever driven a Fiesta it no surprise there are problems.”

Chris McRae, head of policy for Scotland at the Freight Transport Association, said: “Hire companies should always be rigorous in pointing out speed restrictions to those using their vehicles.”

In response, a Transport Scotland spokesperson said: “Initial work has been undertaken to better understand the average speeds by vehicle and road type at a small number of locations across Scotland. “Discussions are planned to consider the findings and agree next steps.”