Your Commute: Tying Up Traffic

There's a report that a MUNI bus managed to snarl all the traffic on 580 after getting in an accident with a big rig? Sure, we can believe a MUNI bus tied up traffic, but what was it doing on 580 in the first place?

And finally, MUNI trains in the city are moving again too, after some kind of unspecified error tied up the downtown tunnel until about 10:15 a.m. This is in addition to yesterday's problems, where damage to overhead wires caused delays on the F and the M.