Around 11:30 p.m. RCMP said it had received complaints about a car driving west in the highway’s eastbound lanes.
When police responded, officers came across a collision scene between a car and SUV.
The collision took place 10 kilometres west of Moosomin, located about two hours east of Regina.
The man driving the car and the occupants of the SUV — a man, two women and one child — were all taken to hospital.
Police did not have an update on their condition.
Highway 1 traffic has returned to normal.