Long delays remain around the A27 in Lancing after the road was closed following a serious accident.
A pedestrian suffered critical injuries after being hit by a car on the eastbound carriageway.
It happened 500m east of the Lancing Manor roundabout and led to the A27 being closed to eastbound traffic between the roundabout and the A283 Steyning interchange.
Motorists have been being diverted via the A2025 Grinstead Lane to join the A259 Brighton Road at South Lancing, crossing the River Adur before returning to the A27 via the A283 Old Shoreham Road/Steyning Road.
It has led to heavy congestion, with some drivers saying it's added three or four hours to their journey time
Latest reports suggest there are now half-hour delays for motorists as police continue their investigations.
The Kent, Surrey and Sussex Air Ambulance flew to the scene following the incident just after 6am this morning. The condition of the pedestrian has not been released. There are no reports of any arrest.
Sussex Police said that a number of people escaped without major injuries from a crash involving three cars on the A27 Arundel Road near Clapham in Worthing.
The accident happened after 4pm on Friday 6th May. The carriageway was closed for the police to carry out investigations.
Queueing traffic and one lane blocked due to broken down vehicle on A27 Eastbound between M27 J9 (Whiteley / Segensworth / Fareham) and M27 J11 (Fareham / Gosport).
A27 Eastbound blocked, delays due to accident, a lorry and a car involved and recovery work between A259 Havant Road (Emsworth) and A259 (Fishbourne Roundabout, Chichester).
Shoreham residents have come together to light up a bridge through the town, in tribute to the victims of last weekend's airshow disaster.
The candle-lit vigil was arranged by organisers of the Shoreham's River Fest event on the Adur Ferry Bridge.
It brought to an end an emotional day of memorial events, one week on from the crash on the A27. Emma Wilkinson was at the vigil:
The part of the A27 that was closed after an aircraft crashed onto the carriageway during the Shoreham Airshow has been partially reopened.
Two lanes are open on the eastbound carriageway heading towards Brighton. One lane has been reopened on the westbound carriageway. The other lane of the westbound carriageway remains shut for police investigation work to continue on the verge of the road.
Sussex Police say the westbound entry slip road at the Adur flyover, from the A283, also remains closed.
A 40mph speed limit is in place and the traffic lights at the Sussex Pad junction, which were damaged in the aircraft crash have been removed.
The A27 remains closed to pedestrians, equestrians and cyclists, and the bus stop on the westbound carriageway cannot be used.
Regarding access to Coombes Road / Lancing College and Sussex Pad -access is for residents only and will be under police control.
HGV drivers wanting to reach the airport or businesses via Old Shoreham Road must make an arrangement in advance with the airport and the police.
Members of the public can access the airport using the A283 and the A259, but there is a maximum vehicle height limit of 2.1 metres.
Memorial events have been taking place this weekend to remember the eleven people killed and others who were injured, when the aircraft crashed onto the A27 on Saturday 22 August.
The A27 near Shoreham, West Sussex, where a vintage Hawker Hunter jet crashed last Saturday, killing 11 people, has partially reopened for the first time since the disaster.
Two lanes have been opened on the eastbound carriageway towards Brighton, along with one lane on the westbound carriageway, Sussex Police said.
The other westbound lane remains closed while investigators continue to work on the verge. A 40mph speed limit has been imposed, police added.
The partial reopening comes a day after thousands of people from communities touched by the crash gathered at memorial events.
Hundreds of people have placed candles to create a "bridge of light" spanning the centre of Shoreham in memory of the victims of last week's air crash.
A series of events have taken place throughout the day, as ITV News correspondent Martha Fairlie reports.
A minute's silence was observed at 1.20pm, the time last Saturday when the vintage Hawker Hunter jet crashed on the busy A27 in West Sussex, and a mass balloon release was held in Littlehampton.
The disaster happened as the 1950s plane failed to pull out of a loop-the-loop stunt during the Shoreham Airshow before crashing, exploding into a fireball