Police say the incident occurred around 7 p.m Friday when a speeding northbound vehicle attempted to pass a number of others on a curve.
The car collided with a motorcycle when it tried to return to the northbound lane.
Two people in their twenties on the motorcycle were knocked off the bike and suffered serious injuries.
The driver kept going and soon collided with another northbound car driven by a woman in her fifties.
Her car went into the ditch and she suffered minor injuries.
The car responsible for both collisions continued north but mechanical trouble brought it to a stop and its driver and a passenger fled on foot.
SQ spokesman Gregory Gomez Del Prado said a police canine unit tracked down one of the car’s occupants — an 18-year-old male under the influence of alcohol.
Del Prado said investigators have yet to determine if the man in custody was the driver and they are continuing their search for the car’s other occupant.
The driver could face a number of charges including reckless driving.
Del Prado said the two people on the motorcycle that was hit are in stable condition in hospital.