When in Rome. If Philly is anything like NJ and NYC the cyclists don't even slow down at controlled intersections. I rode for 30 years like that. In Portland the VAST majority of cyclists observe red lights to a fault and do at least a touch and go at stop signs. I stop for lots more red lights now because that is the culture. Give it time. You will learn soon enough which signs and lights get taken seriously and which ones get blown off. As always, however, only you know how much money you have to work with. Bet with your head, not over it.