PORTLAND, Ore. -- An ambulance with its emergency lights on collided with two cars in downtown Portland on Friday morning.

The collision at Southwest 15th Avenue and Morrison Street disrupted MAX service and TriMet had to shuttle riders between downtown stations between 8 a.m. and 9 a.m.

Investigators said the ambulance entered the intersection after the light turned red and it hit two cars. Paramedics were on their way to a report of an overdose near the scene of the collision, police said.

There were no life-threatening injuries in the crash, but the driver of one of the cars, 39-year-old Tin Hoang, was taken to Oregon Health & Science University Hospital.

Police said there was no evidence showing speed or impairment as factors in the collision.