The four men, aged between 20 and 25, were seriously injured after their car rolled along Drakeford Drive in Greenway about 11pm.

Police suspect excessive speed may have caused the accident, which took place between Erindale and Isabella Drives in Greenway.

The car rolled and came to a stop on the other side of the road, in front of oncoming traffic.

One of the men was thrown from the car, and it is unclear whether he was wearing a seatbelt.

The crash left all four with serious injuries, and they were rushed to Canberra Hospital.

''We're lucky on this occasion that nobody was killed, either in that vehicle or in another vehicle,'' traffic operations Sergeant Rod Anderson said. ''We're just imploring with people to slow down on our roads.''

Three were in a serious but stable condition and one was in a serious condition in hospital last night.

There were no other vehicles in the area at the time, according to police.

''The vehicle ended up on the other side of the road in the oncoming traffic and it could have been a much worse situation than what we had,'' Sergeant Anderson said.

''We're warning young people that this sort of dangerous driving does result in serious collisions and possibly injury,'' he said.

''We're simply going to target those sort of high speeds, and apprehend those people involved.''

The ACT's road toll is 10, which is up from the all-time low of six deaths recorded last year. The toll is lower than 2010, when 18 people died.

Police have called for anyone who may have seen the car before the crash to contact Crime Stoppers on 1800 333 000. Christopher Knaus