A rollover collision involving three vehicles closed the flyover from Highway 7/8 southbound to Highway 8 for several hours.
Police responded to the crash just south of Ottawa Street around 2:40 p.m. Friday.
OPP Sgt. Dave Woodford says a Dodge Avenger made a last minute maneuver to get onto the ramp but hit a barrier and rolled on top of a Nissan Altima.
The two vehicles then struck a third vehicle, a Hyundai.
Ambulance and fire crews were called to the scene and six people had to be taken to Grand River Hospital. Police say their injuries are serious, but not life-threatening.
The male driving the Altima was later airlifted to Hamilton General Hospital with life-threatening injuries.
OPP remained at the scene to investigate into the evening, keeping the ramp closed until around 7 p.m.
Charges are pending, though Woodford says a number of interviews still need to be conducted and information collected.