Major southbound A3 road at Guildford shut for 32 hours
A busy stretch of the A3 in Surrey will be closed for 32 hours over the weekend.
The southbound carriageway would be closed near Guildford from Saturday night, the Highways Agency said.
Structures manager Steve Cobb said a bridge carrying the A3 over a railway line was being resurfaced and waterproofed.
He said crews would try to finish sooner than planned but work was due to continue until 06:00 BST on Monday.
Mr Cobb said the closure near the university and cathedral, from 22:00 BST, would be from the A320 Stoke interchange to the A31 junction with the Hog's Back.
'Extra time needed'
He said: "We're asking people perhaps to think of alternative routes, if they are thinking of going down to the coast for the day."
Fully-marked diversions would be in place, but Mr Cobb said there was "potential for congestion".
He said: "Because of the through traffic that travels southbound on the A3, we are really seeing that there will be some queue lengths on the diversion route there."
He said people heading for the south coast could use the M25, M3 and M27 instead, because they would need to allow extra time to use the diversion route on the A3, but added that it would be "good advice" to avoid the A3 if possible.
Mr Cobb said: "We've tried to plan around this. We did consider trying to close just half of the carriageway at the time, but for safety reasons we've got to close the whole lot and do the work all in one go."
Two further overnight closures are also planned on the southbound carriageway on Monday night and the northbound carriageway on Tuesday night, both from 22:00 BST to 06:00 BST, with diversion routes in place.