05/25/2012 08:31 EDT | Updated 07/25/2012 05:12 EDT

3 critical in Halton single-vehicle accident

Halton Regional police now say three of the people involved in a Friday morning accident on a country road are in critical condition in hospital.

Two men and two women — all in their late teens or early 20s — were badly injured when their Honda Civic went off the road on Halton 5 Side Road, at about 4 a.m.

Police do not believe any other vehicles were involved — that the Honda missed a curve in the road and rolled over.

"Patrol officers responded and found two males and a female outside of the badly damaged car. Another female was located in the back seat of the vehicle," said a release from police.

The woman found inside the car was treated and released from hospital.

"The three that remain in the Toronto trauma centres [Sunnybrook and St, Michael's hospitals] are deemed to be in critical condition," police said.

Police said that according to their preliminary investigation, "indications are that speed and alcohol are contributory factors in the cause of this collision."

Police say they are not releasing any names at this time. "However [police] can confirm that the two females; ages 19 and 21 are from Milton and the two males; also of ages 19 and 21 are from Mississauga."