Road traffic officers and control room staff are to launch a two-day strike in the latest outbreak of industrial action sweeping the country.
Members of the Public and Commercial Services union (PCS) working for National Highways in South West England and the West Midlands will walk out on Friday.
Other National Highways workers will strike on January 3 and 4.
The union said the action is likely to have an impact on signs and signals being set up to warn motorists of blockages and incidents, a reduced ability to respond and deal with collisions, and delays in reopening carriageways and motorways.
PCS general secretary Mark Serwotka said: “Previous strikes elsewhere in England have caused disruption for people travelling over the Christmas period, and this strike is likely to do the same.
“While we regret people’s travel plans will be affected, we make it very clear this strike could be called off today if the Prime Minister or Chancellor put money on the table.”
Border Force workers in the PCS based at a number of airports are continuing with strike action until New Year’s Eve.
Military personnel will continue to cover for striking workers at Heathrow, Gatwick, Manchester, Birmingham, Cardiff and Glasgow airports, as well as the Port of Newhaven.
The dispute is over pay, jobs, pensions and conditions, with more strikes set to be announced in the new year.
Duncan Smith, executive director of operations at National Highways, said: “The PCS strikes involve a small minority of frontline operational staff. We have well-rehearsed resilience plans to continue managing and operating our network safely, and we’re confident that this action will have minimal overall impact.
“Millions of people rely on our roads and there is a possibility that they may be busier than usual on strike days, particularly when they correspond with industrial action on other transport modes. We’d urge drivers to take extra care during the cold weather.”