The M25 in Surrey has been partially reopened in both directions after a crash in which a lorry went through the central reservation and hit a car.
Three people were seriously injured in the collision, between junctions seven with the M23 and eight with the A217, on Friday afternoon.
Two clockwise lanes of the motorway were reopened about 15:00 BST on Saturday, the Highways Agency said.
Two lanes of the anti-clockwise section opened at 18:30 BST.
Long delays were reported on Saturday on the M23 and A23 in Surrey, the A22 at Godstone, the A217 and Reigate town centre because of traffic unable to use the M25.
"Diversion routes are working but they are very slow moving," said a spokesman for Highways Agency.
"Drivers should avoid the area if possible, or if they cannot they should allow a considerable amount of additional time for their journey."
The crash caused the lorry, which went through the central reservation and hit a car on the opposite carriageway, to spill diesel on the anti-clockwise road and shed its load on the clockwise carriageway.
A Nissan Micra and two other vehicles were also involved in the incident, just after 16:00 BST.
The lorry driver and a man and a woman, who were in the Micra, were taken to hospital with serious injuries.
At one point, tailbacks of up to 28 miles were reported.
Overnight, the Highways Agency said it needed to remove the lorry, which was "in pieces", from the carriageways.
A spokesman said then the carriageway needed resurfacing because of diesel and other damage to the road.
The crash caused stationary traffic on Friday evening to build up between junction 10, at the Wisley Interchange, and the Clacket Lane services - between junctions five and six - on the Kent and Surrey border.
A police investigation into the cause of the crash has begun.
Gatwick Airport warned passengers of road delays in the area and said people should check for updates on the BBC and Highways Agency websites.
Footballers from AFC Bournemouth were travelling to London from Bournemouth on Friday ahead of their match with Charlton.
Assistant manager Steve Fletcher said they had left Bournemouth at 13:30 BST and expected to be at their hotel for a meal about 17:00 BST.
They were stuck in the queues for about six hours and arrived after midnight.
He said the players had been able to leave the coach, do some stretches and play "keepie-uppie" on the hard shoulder.
"In my 22 years of travelling as a pro, I've never seen anything like it," said Mr Fletcher.
"It was out of the ordinary to say the least. We had water but I feel sorry for the people who were stuck in cars without food or water."
- 6 August 2011