THE Southwick Tunnel will be closed in both directions for routine maintenance over two nights.
The closure will mean drivers will not be able to use that section of the A27 on Friday and Saturday, from 8pm to 6am.
The Highways Agency said: “A fully-signed diversion route will be in place via the A270 (Old Shoreham Road) and A293.
“The road improvements could be subject to change due to weather conditions or unforeseen circumstances. All our improvement work is carried out with the aim of causing as little disruption as possible.”
Drivers on the A27 are also affected by resurfacing, drainage and street lighting works in Worthing this week.
The road is due to be closed overnight for five days between Clapham and the Offington Roundabout, starting yesterday.
The diversion route uses Long Furlong and the A24 in both directions.