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Jeff Chiu, Associated Press
In this March 19, 2015 photo, Clean City attendant Erica Corona, left, watches as Sabrina Hollier walks up a step to use a public toilet at the Tenderloin Pit Stop in San Francisco. Not far from the fancy stores of San Francisco’s Union Square, solar-powered flushing toilets on wheels roll in four afternoons per week in the dense Tenderloin neighborhood.

SAN FRANCISCO — Streets in San Francisco's Tenderloin neighborhood blocks away from fancy stores and long lines of tourists waiting for cable cars have been cleaner since solar-powered toilets began rolling in four afternoons per week.

The city's mobile bathrooms are guarded by attendants and have been so successful that officials say Honolulu, Portland and New York already have inquired about them in seeking solutions to similar sanitation problems.

Supporters of the pilot program say having public bathrooms accessible has made the neighborhood known for crime, homelessness and poverty more livable.

San Francisco Supervisor Jane Kim supported the program's creation. She says the toilets afford "people some dignity to take care of a human need."