A major route to the Channel ports is to be closed overnight for more than a month before 29 March.
Temporary steel barriers are to be installed on the M20 in Kent in preparation for possible delays caused by a no-deal Brexit.
The motorway will be closed overnight from Saturday until mid March, Highways England said.
The work, as part of Operation Brock, is designed to keep traffic flowing in Kent if there are cross-Channel delays.
Under Operation Brock - when the volume of traffic becomes too large - a section of the M20 would become a contra-flow system on one side of the carriageway. Lorries would queue on the opposite carriageway.
Operation Brock will also provide parking for lorries at Manston Airport in the event of disruption at the Port of Dover and the Channel Tunnel terminal at Folkestone.
The road closures will take place between junction nine for Ashford and junction seven for Maidstone between 20:00 and 06:00 GMT.
Diversions will also be put in place on the A20 with drivers being warned to expect delays.
From 12 February until mid March there will be narrow lanes and a 50mph speed limit on the same section for day-time traffic.