The installation of average speed cameras on the A9 has slowed drivers down in advance of them being switched on, according to Transport Scotland.
Transport Scotland says that prior to installation one in three drivers were exceeding the speed limit on the stretch between Perth and Pitlochry, but this has reduced to one in 10 following installation of the cameras.
Keith Brown, Scotland’s transport minister, said: “The A9 Safety Group is clear that average speed cameras are effective in saving lives and this is backed up by the facts.
“Before and after studies of other average speed camera sites in the UK show a reduction in accidents. On average, they achieved a 61% reduction in fatal and serious accidents. Average speed cameras encourage drivers to improve their behaviour and we are already seeing this on the A9.
“The Group is also taking forward measures to improve driver awareness of speed limits and to encourage safe overtaking on the route.”
In a move to “reduce driver frustration”, the Scottish Parliament has approved legislation which will allow the HGV speed limit to be raised to 50 mph on single carriageway sections of the A9 when the cameras become operational in October 2014.