A road-rage incident on Monday involving a bicyclist and a car driver resulted in the arrest of a Bolinas man who intentionally struck a San Francisco cyclist, according to the California Highway Patrol. Patrol officers took Bolinas resident Mark Rafferty, 62, into custody after he allegedly ran down 25-year-old Charles Keane-Zirepolo, of San Francisco on Point Reyes-Petaluma Road west of Nicasio Valley Road. Neither Mr. Rafferty nor Mr. Keane-Zirepolo could be reached for comment. But heavy bike traffic, particularly on the weekends, has increasingly become a concern in West Marin. According to highway patrol, Mr. Keane-Zirepolo was riding with another bicyclist when he veered into the eastbound traffic lane directly in front of Mr. Rafferty, who was driving a green Saturn sedan. Mr. Rafferty attempted to pass the bicyclists by crossing the yellow line into the westbound lane, but Mr. Keane-Zirepolo also crossed into the westbound lane, again blocking Mr. Rafferty and forcing him to hit the brakes hard. Mr. Rafferty then pulled to the right shoulder, exited his sedan and yelled at Mr. Keane-Zirepolo, who rode past Mr. Rafferty and “displayed an obscene hand gesture.” Returning to his sedan, Mr. Rafferty pursued Mr. Keane-Zirepolo and—according to highway patrol—purposefully drove into the bicycle’s rear, which crushed the back wheel and catapulted Mr. Keane-Zirepolo onto a dirt hillside. He declined medical treatment and paramedics released him. Mr. Rafferty was arrested for assault with a deadly weapon and booked into the Marin County Jail; he has since posted bail and is scheduled for an August 21 court appearance. Last year, there were 28 reported incidents between bicycles and vehicles in Marin County, including 4 felony hit-and-runs, according to highway patrol data. But Monday’s incident was the first instance of a serious altercation involving a bicyclist and a motorist in West Marin this year, according to Officer Andrew Barclay, spokesperson for the highway patrol. Tensions between bicyclists and motorists have long been strained in West Marin, where large groups of cyclists routinely flood roadways and towns during weekends and the summer season. A lack of bicycle lanes combined with heavy tourist traffic is a major source of concern for local residents, many of whom met in early July to discuss issues such as bicycle and vehicular safety and traffic-control measures during a meeting of local businesses at the Dance Palace.