A mentally disabled Petaluma man who has found perhaps too much freedom on his bicycle was found safe and sound in Vallejo late Tuesday night after going missing for the fourth time, police said.

John Wirth, 49, was being evaluated at a local hospital while he awaited a ride home to Petaluma, Petaluma police said.

Wirth, who suffered a traumatic brain injury in a near-fatal motorcycle crash half his lifetime ago, moved to Sonoma County about a year ago with his sister, Mary Ann Grant, who has encouraged him to explore his new neighborhood on his bike.

But Wirth has been ranging farther and farther since turning up in Bodega Bay several months back and in mid-May disappeared for nearly two days before he was found in St. Helena, police said.

A month later, he was again missing overnight and turned up in Fairfield, police said.

His sister reported him missing again on Monday night, saying her brother had gone off early in the day on his bicycle and failed to return. Police notified neighboring counties given his recent far-flung rides.

He was found in Vallejo shortly before 11:30 p.m. Tuesday by civilian who found him sleeping somewhere in public, police said.