You can’t ride your Segway in the City by the Bay anymore. As of today — just about a month shy of going mainstream — the Segway Personal Transporter has been banned from San Francisco sidewalks for safety reasons. San Francisco Mayor Willie L. Brown Jr., who a year ago joined the hoopla celebrating Segway’s introduction, let pass a city ordinance banning the high-tech scooter when the city’s Board of Supervisors recently voted 9-2 to outlaw the Segway on city sidewalks, spokesman P.J. Johnston said. Brown earlier had said he opposed the ban, and would veto it, “because he thinks...