A Pleasant Hills man was critically injured yesterday morning when his motorcycle crashed into the rear of a tour bus on Fifth Avenue in Oakland, police said.

Daniel Ridenour, 25, was riding his bike west at about 7 a.m. in the 3400 block of Fifth Avenue when he attempted to change lanes to pass another vehicle.

He swerved into the right-hand curb lane and accelerated, but a Lenzner tour bus was in his path in that lane.

The motorcycle slammed into the rear of the bus.

Investigators said the bike left a 30-foot long skid mark before the collision.

Mr. Ridenour was taken to UPMC Presbyterian.