I feel more uncomfortable riding in Philly than I did in New Orleans, where people fairly routinely got mowed down (sometimes killed dead) by drivers...myself included (except not killed dead). the difference is, it seems, that in N.O., people were just oblivious to their surroundings, whereas in Philly people are aggressive and mean-spirited. that said, I would much rather bike in center city than in the outlying areas like Manayunk, where I live. jerks. morons. cavemen abound.
considering what a hostile environment exists here, hats off to everyone who rides a bike. I'm getting older and more nervous and find myself sticking to actual bike trails and quiet streets. these car folks scare the bejeebus out of me.