It's pretty remarkable how buses in other cities manage to adhere to the published schedule, but MUNI can't seem to manage. I've ridden buses all over the world, and MUNI is absolutely the worst at scheduling or latency. It's almost like they aren't even trying.

And even if you drop the requirement of "stick to the schedule", they still suck: you can have two lines running the same route up a major thoroughfare (e.g. 47/49 on Van Ness), and you'll still routinely get three busses back-to-back, followed by 45 minutes of delay. The only reasonable scheduling mechanism I've found for MUNI is to know exactly how far away the next bus is from your stop. Without real-time position information it's an unusable system, because arrivals are essentially a poisson process.