There is queueing traffic on A259 New Road both ways from Roundstone Lane to B2140 Station Road in the construction area, the AA said. A lane closure is in place.
The A27 Old Shoreham Road is partially blocked eastbound with slow traffic due to a medical incident after A2025 Grinstead Lane (Sompting Roundabout). Police are at the scene.
There is an emergency road closure on the A285 High Street Duncton between south of the entrance to Seaford College and the junction of Beechwood Lane following a slippage of earth over a culvert that spans beneath the carriageway.
Businesses remain open and signs in place to aid with the diversion.
No trains will run between London Victoria and East Croydon while Network Rail South East carry out works this weekend, Southern Rail said.