Fewer people were killed or seriously injured on the A9 in the year after average speed cameras were introduced, Transport Scotland says.

Two fewer people died and 16 fewer people were injured between Dunblane and Inverness from November 2014 to October 2015.

The total number of people killed or seriously injured on the road between Perth and Inverness fell by just over half.

Transport Scotland said a downward trend in accidents on the notorious road continued in the second half of the year.

But experts cautioned that it will be another two years until the impact of the average speed cameras can be properly assessed.

Transport minister Derek Mackay said: “For the first time since parts of the A9 were upgraded in the 1970s, there were no fatal accidents anywhere on the route from July to December.

"These improvements are taking place with rising traffic volumes and the continuing use of this nationally important route to support the economy of the Highlands and Islands.

“We are monitoring the performance of the A9 and welcome the figures which indicate that the route continues to perform far more safely than before.

"Fatal and serious casualties have more than halved and there are clear and substantial reductions in fatal casualties both between Perth and Inverness and between Perth and Dunblane.

“Every road death is one too many and that is why we remain steadfastly committed to reducing casualty numbers even further as we continue to work with all our partners to reach our ambitious targets for 2020.”

Average speed cameras were installed in a bid to cut down down on serious accidents and reduce speeding.

The number of vehicles exceeding the speed limit on the A9 fell from around one in three to one in 15 following their introduction.

Average journey times have increased by between one and nine minutes, according to Transport Scotland.