Two drivers were killed and two teenage passengers left seriously injured in a crash on a notorious stretch of road.
A women in her 40s and a man in his 60s were killed in the head-on collision between a green Ford Ka and a white Nissan 300ZX sports car on the A259 between Eastbourne and East Dean, near Seaford.
The drivers, who police say lived close the site of the accident, both died at the scene of the 9.30pm collision on Thursday.
A 17-year-old girl in the Ka and an 18-year-old woman who was a passenger in the Nissan were taken to Eastbourne District General Hospital following the crash.
They were tonight still being treated for serious but not life-threatening injuries.
The crash adds to the rising death toll on the A259 and happened close to a stretch of road recently named one of the most dangerous in the country.
The A259 between Eastbourne and Hastings has the highest proportion of accidents in the South East according to a list by the Road Safety Foundation.
The group named the 16-mile single carriageway stretch of the A259 as of medium to high risk to motorists.
Eastbourne MP Nigel Waterson said: "It's a highly dangerous and congested road and it is certainly one of the worst in the country.
"It is clearly outdated for modern motoring conditions and the volume of traffic using it means many people take risks overtaking."
Officers from Sussex Police's road policing unit in Polegate are investigating the collision and have issued an appeal for witnesses.
Anyone with information should call 0845 6070999 quoting Operation Corley.