The Highlands' Stromeferry Bypass could be closed for several weeks next spring to allow for work to remove unstable rocks.
Highland Council said the work costing about £1m will be one of a series of projects designed to better protect the stretch of A890 from landslides.
The local authority is also looking at a long-term solution to the problems at the 1960s-built bypass.
It was closed by 10 significant rock falls between 1990 and 2012.
The Stromeferry Bypass helps to connect Lochcarron to Plockton, and its high school, and eventually with Kyle, on the opposite side of Loch Carron.
The road runs across the top of the sea loch to link up with the A896, the main road to Lochcarron.
When the bypass is closed, drivers face having to take a 140-mile (225km) diversion, instead of the usual 18 miles (29km) from Lochcarron to Plockton.
After a landslide in December 2011 the bypass was shut for four months.
Solutions to the problem include re-routing the road at an estimated cost of £85m, a bridge costing about £100m and a tunnel costing about £171m.