The A82 is a vital artery for communities in the western Highlands, linking Fort William, the Highlands and the Western Isles with Glasgow and the Central Belt.
However, many sections of the road date back to the 1920s and the route is much narrower in places than it would be were it to be built today.
The programme covers areas including Pulpit Rock, Crianlarich and Tarbet to Inverarnan.
A new bypass has been constructed in order to tackle the delays experienced by road users during the busy tourist season.
The A82 at Pulpit Rock has offered a significant engineering challenge for decades.
Since completion of the improvement works in May 2015, road users are now able to pass through this section of the A82 without stopping at traffic lights.
Tarbet to Inverarnan
Tarbet to Inverarnan route
Transport Scotland have commissioned CH2M Fairhurst Joint Venture to look at options for upgrading the A82 between Tarbet and Inverarnan.
The route runs adjacent to the west bank of Loch Lomond.