The eastbound lanes of SR 520 were closed just west of Montlake Blvd. for more than an hour Tuesday afternoon due to a multi-vehicle collision.
Eleven people, including nine from bus, suffered non-life threatening injuries.
The collision involved a tour bus and three vehicles.
A UW student involved in the crash said it happened so quickly he isn't sure how it started.
The Washington State Patrol said the bus struck the rear of a vehicle, causing a chain reaction into two other cars.
The bus driver and people in the first vehicle hit suffered broken bones.
All patients were taken to Harborview, WSP said.
The I-5 off-ramps to SR 520 were also closed for more than an hour.