Greyhound, long the leading name in intercity bus service, is gradually vacating most of its remaining bus terminals around the country. And riders, and cities, are left holding the bag.

In Philadelphia it started late last month, when Greyhound left its long-term home at a station in Center City and joined a group of curbside bus operators on Market Street near Independence Hall. Suddenly, travelers who’d been accustomed to shelter, shade and restrooms found themselves on the sidewalk, waiting sometimes hours in escalating heat for a bus. With a growing number of buses idling at the curbside, taking up a travel lane that’s supposed to be dedicated to bikes and local public transit buses, city officials had a problem on their hands.