The A272 at Cowfold remains closed after a serious collision involving a van and tanker lorry just before 9am.
Investigation work is being carried out between the Maplehurst turn off and Stonehouse Lane (Peartree Corner), and disruption is expected into the evening.
Meanwhile, from 6pm a ‘bike swarm’ will be taking place at The Level in Brighton.
Environmental activism group Extinction Rebellion has organised the event, which aims to celebrate World Car Free Day and support new cycle lanes in the city.
Elsewhere in Brighton, emergency repairs have been completed on the A23 London Road at Patcham and traffic is said to be easing.
Roadworks are causing delays on the A259 Littlehampton Road in Littlehampton, with slow traffic both ways between B2140 Station Road and A280 Angmering Bypass (Blue Star Roundabout).
There are reports of slow traffic due to roadworks on A29 Stane Street at Billingshurst, both ways from High Street to Okehurst Lane.
And over in East Sussex works on the A27 Polegate Bypass are causing hold-ups, with queueing traffic reported both ways between The Thoroughbred Pub and A22 Polegate Road (Cophall Roundabout).
There is currently queueing traffic on the A259 Little Common Road in Bexhill On Sea, due to roadworks near the B2182 Cooden Sea Road (Wheatsheaf Inn).
Bodiam Road in Sandhurst is closed both ways due to emergency repairs from Silverden Lane to A268 Queen Street.
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