The work is due to start on January 20 and last for up to three weeks.
The agency also issued a warning that starting early next month there will be further disruption south of Drumochter.
He says an effort was made to ‘to deny the delays were because of failures by anyone in government or that uber-quango Transport Scotland’.
But in what is a major positive the Scottish Government appears open to accelerating work on the deadliest sections.
‘All Highland roads being treated including footpaths’
Scammers are targeting Highland rail passengers with fake unlimited travel deals, ScotRail has warned.
Tough conditions set to continue - but so are Highland snow plough champions
But goods vehicles could see the speed limit increase on single and dual carriageways by 10mph.
The Met Office has extended a snow & ice warning into Friday for the Highlands, Moray and Aberdeenshire. It follows widespread disruption on Thursday.
Snow showers and ice will bring further disruption to travel in the Highlands and Moray as a yellow weather warning has been extended.