Senior politicians row over A9 average speed cameras plan
Two senior politicians have become embroiled in a row over plans to install average speed cameras on the notorious A9.
Highlands MP Danny Alexander wrote to the Scottish government's Transport Secretary Keith Brown saying the move was a "knee-jerk decision".
But Mr Brown's spokesman accused the UK government minister of "hypocrisy".
It is hoped the cameras will improve safety on the road, but Mr Alexander said he wanted to see evidence they would prevent accidents.
The Scottish government has pledged to upgrade 80 miles (128.7km) of single carriageway between Perth and Inverness to dual carriageway.
However, because the project will not be completed until 2025, average speed cameras between Dunblane and Inverness will be installed.
Holyrood ministers said the A9 Safety Group, which includes representation from Perth and Kinross Council and Highlands Council, "reviewed a detailed evidence base of the accident history and speed profiles of the route" before reaching its decision.
Mr Alexander, Lib Dem MP for Inverness, Nairn, Badenoch and Strathspey, said: "It is clear the high speeds are a significant factor in some of the horrific accidents we have seen on the A9 and I would support the targeted use of speed cameras at blackspots.
"But it is also clear that some of the dangerous driving on display is caused by frustrated drivers caught in very long queues behind lorries and tankers. That frustration is only relieved by dual carriageways and by hauliers politely pulling over to let queues past.
"I'd like to see the full assessment of all the options for road safety improvements published, so we can all see how the average speed proposal compared to other options which I presume were on the table, like a more targeted approach."
A spokesman for Mr Brown responded by saying: "This is the height of hypocrisy from Danny Alexander, given the Lib Dems' utter failure to commit to dualling the A9 during the years they were in office at Holyrood.
"People know that Mr Alexander's first loyalty is to the Treasury, not to the Highlands and its transport needs, something underlined by his failure to fight properly to protect key flights to the region."
The average speed camera system on the A9, which is due to be up and running by next summer, will be the second in Scotland.
The first was installed on the A77 in Ayrshire between Bogend Toll and Ardwell Bay in 2005. It has been credited with improving safety.
Transport Scotland said it had delivered a 46% reduction in fatal accidents and 35% cut in serious accidents.
The cameras read the number plates of passing vehicles and measure the time it takes for them to pass from point A to point B, measuring average speed.