Police said according to witness reports, a car lost control and hit the guardrail at about 9 p.m. on the southbound ramp to Glenmore Trail.
Witnesses told police the driver got out and jumped over the railing onto the ground below. It appeared he was trying to flee the scene by going over the guardrail, though police acknowledged he may not have known he was on a bridge deck.
Witness reports suggest he was impaired.
EMS said the driver, believed to be in his late teens, was taken to hospital in serious condition. Police said his condition had been upgraded and was no longer life-threatening as of Wednesday.
Paramedics said the passenger, a man believed to be in his 50s, was taken to hospital with minor injuries.
With files from Gerri Dietrich