Closed for the San Francisco marathon. And subway not in service for testing of new train. Sergio is riff at Golden Gate Bridge and they say its security concerns. Reporter over the last year or so, Law Enforcement agencies have been watching in europe as terrorists use vehicles to kill pedestrians. Decided they needed special precautions for the marathon tomorrow. For three hours drivers will not be able to head north across the Golden Gate Bridge to marin county. Traffic coming into the city still open but Center Barrier in place to protect the runners. Years past used plastic traffic cones but after a year of attacks in europe where dozens of people have been killed by terrorists using vehicles as weapons. Golden gate Bridge Authority decided it was no longer option. This will be the second day that moo muni subway was closed to customers. Frustrating. Delighted to have new trains but not working well. Reporter saw passengers frantically getting to get to trains stopping short and b