National Highways reported at 6.25pm that lane one (of two) was closed on the A27 westbound between A270 and A283 near Shoreham-by-Sea ‘due to a collision’.
A post on X (formerly Twitter) added: “Emergency services are in attendance.
“There are approximately 2.5 miles of congestion on approach, causing 40 minutes delays above normal travel time.”
West Sussex Fire and Rescue Service, which had crews support police officers at the scene, also issued a statement on social media.
This read: “We are at the scene of a road traffic collision on the A27 westbound near Shoreham. Crews from Shoreham and Worthing in attendance.
"Please avoid the area to allow our crews to work safely.”
The fire service advised motorists that the westbound carriageway was ‘likely to remain closed for some time’, and drivers were ‘urged to find an alternative route’.
In an update at 7.45pm, National Highways said traffic had been temporarily stopped on the A27 westbound ‘to allow emergency services to work safely at scene’.
Traffic had been released by 8pm but the lane closure remained in place for recovery work.
The Government agency added: “There are delays of 30 mins above normal travel time.”
A further update at 8.30pm read: “All lanes are now reopen. Delays clearing well in the area. Have a safe journey.” Click here for an update from the emergency services and more photos from the scene.
AA Traffic News reported that the road was partially blocked following a collision on the A27 westbound at A270 Upper Shoreham Road (Southwick / Holmbush turn off).
The AA also reported that there were delays increasing on the A27 Shoreham By-pass Westbound between A293 (Portslade / West Hove turn off) and A283 Steyning Road (Steyning turn off).
1. A27 partially blocked following collision
The A27 was partially blocked following a two-car collision on Thursday evening (July 18). Photo: Sussex News and Pictures