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BOB HIRSHON (host):
Calculating the perfect bus schedule. I’m Bob Hirshon and this is Science Update.
A new mathematical model could make waiting for a bus less frustrating. It was developed by University of Southern California engineering professor Maged Dessouky and his colleagues. Dessouky says that scheduling buses is surprisingly complicated. That’s because most schedules need to build in something called slack – in other words, extra time for traffic delays — without making service too infrequent.
MAGED DESSOUKY (University of Southern California):
So it’s a tradeoff between service reliability and service frequency, in trying to figure out what the optimal slack is. It turns out that a slack of between 10 and 20% is good.
HIRSHON:
Dessouky’s model is especially precise because it takes into account the variability of local traffic patterns. He says the more the local traffic varies, the more slack is needed. I’m Bob Hirshon, for AAAS, the science society.