Earlier that month, two lorry drivers died in a collision on the A9 north of Blair Atholl in Perthshire.
On August 26, married couple Robert and Valerie Macdonald, from the Scorguie area of Inverness, were killed when the motor tricycle they were travelling on crashed at Findhorn Bridge.
The Scottish Government has said work to upgrade the trunk road to a dual carriageway will begin two years ahead of schedule.
The £3 billion programme will start at Kincraig, south of Aviemore, as part of the overall aim to improve seven sections of single carriageway over 80 miles.
Tayside Police's road policing Inspector Julie Robertson said: "Despite our best efforts to encourage motorists to drive responsibly and within the speed limits, there is still an alarming number of people detected not doing so."