A bicyclist was killed about 5 p.m. Thursday after colliding with a Muni bus.

The wreck involved a 44 O'Shaughnessy bus at Sixth Avenue and Clement Street, police and Muni officials said.

The bicyclist, declared dead at the scene, was described as a white male, age 25 to 30. He had not been identified, said Sgt. Michael Andraychak.

The bicyclist and the bus were both traveling north on Sixth Avenue, Andraychak said, when the bicyclist made contact with the right front of the vehicle.

Muni spokesman Paul Rose said the bus driver, who has worked for Muni since July 2008, will be tested for drugs and alcohol.

"The driver appeared shaken," Andraychak said.