An enabling ordinance that allows the Board of Supervisors to place limitations on oversized vehicles parked on county-maintained roads was amended this week to allow rules that curb daytime parking in addition to overnight parking. After July 20, the board can apply a rule that prevents the daytime parking of oversized vehicles; another rule would prohibit parking commercial vehicles longer than 22 feet at any time. The ordinance, passed earlier this year, authorizes supervisors to impose restrictions after assessing roads on a case-by-case basis and holding a public hearing. So far, three areas have been identified, each located within unincorporated parts of San Rafael. Bob Goralka, the transportation manager for the Department of Public Works, told the board on Tuesday that the ordinance has been successful in preventing extended parking in two of these areas, but that daytime parking of trucks and R.V.s in the Lomita Park neighborhood have created visual obstructions and loitering. Lieutenant Steve de la O of the Marin County Sheriff’s Office said he was unaware of extensive parking complaints in West Marin. “It seems everything is being driven from San Rafael,” he said. Yet Point Reyes Station resident Tom Quinn, who lives on C Street near the entrance to the Giacomini Wetlands, said littering and vagrancy are a real problem in his town. Mr. Quinn spoke in support of the ordinance when it was passed in January and, as a member of Point Reyes Station Village Association, helped author a letter to Supervisor Dennis Rodoni that requested that the board apply the ordinance on most streets in town, including the entire lengths of B and C Streets and Second through Sixth Streets. He said Mr. Rodoni chose to recuse himself from all conversations on the issue, saying he owns property on C Street, but that Supervisor Rodoni organized a call between a county officer and the village association scheduled for later this week. In Bolinas, numerous residents along Brighton Avenue have complained for years about people living in their vehicles and the associated impacts that turn public space into private space. In recent months, the Bolinas Community Public Utility District formed a committee on vehicle habitation to generate ideas for addressing the issue.