Banners waived and bodies shook to the beat of "Come on Ride It," the 1996 single by Quad City DJs, Thursday as seven members of the Action Committee for Transit, a local organization advocating for the Purple Line, dodged raindrops to let people know why they thought the Purple Line was essential for Montgomery and Prince George's counties.

Their numbers were small, but their message was clear.

"The Purple Line would be a driver for both the environment and business. It would make Bethesda and Silver Spring hubs," Ben Ross, a Bethesda resident and flash mob participant, said. "You can get in and out of D.C. from the north and south, but you can go east and west."

The Purple Line would get people out of their cars and help clear congestion, Peter Gray, a Silver Spring resident who stopped to watch the flash mob, said.

"It's also great for people who don't have cars," Gray said.

The idea for the flash mob came from a group in Baltimore that is similarly trying to get more mass transit in the area. Members of Red Line Now, a group advocating for a proposed 14-mile-long light rail project that will connect East and West Baltimore with downtown Baltimore, contacted the Action Committee for Transit to team up across the state, said Ted Van Housen, a board member for Action Committee for Transit.