Police say Mattie Isaac Forga forced his way into a woman's car in Novato.
The 62-year-old victim said the suspect yelled something about a pregnant woman going into labor. The victim drove down 101 and exited at Alameda Del Prado, where she stopped the car and began screaming.
The suspect ran away and was arrested a short time later. Police believe the same man may have tried to flag down other drivers before he was captured.