Walking Philadelphia's streets since Tuesday's storm has been like an arctic version of Super Mario Brothers.

Unshoveled patches on walkways require pedestrians to hop, tiptoe, and, unfortunately, slip and slide toward their destination. Particularly bad, even in the city's most heavily traveled areas, are snow piles left uncleared from crosswalks and curb cuts.

For the most agile walker, the snow-blocked intersections call for some acrobatics. For the less mobile, unshoveled snow is paralyzing.

"The biggest problem really for us so far is curb cuts," said Liam Dougherty, 27, who uses a wheelchair. "It's no-man's land, where no one is responsible."

A snow-filled curb cut at Chestnut and Second Streets

He was unable to get from his home at 48th and Pine to work in Center City at Liberty Resources, an advocacy group for the disabled, because of the obstacles to using sidewalks.

Plowing is part of the issue, said Richard Montanez, the chief traffic engineer at the Philadelphia Streets Department. Plow operators are asked to not pile snow at pedestrian access to intersections, but if cars are parked on the street, particularly if they are too close to the curb cut, snow will collect where pedestrians pass. Responsibility for clearing sidewalks lies with property owners in Philadelphia, who are required by city ordinance to clear a 36-inch-wide path through snow. The owners of corner properties are responsible for clearing curb cuts that give access to intersections, Montanez said.

Among the slippery stretches of sidewalk Thursday was at least one outside a SEPTA subway stop.

The authority does not own that land, SEPTA spokesman Andrew Busch said, and is not responsible for shoveling it. The authority does clear sidewalks at bus stops and shelters between Second and 30th Streets through an agreement with the city.

"We had those cleared approximately eight hours after the storm ended," Busch said. "The significant ice made this cleanup difficult."

The city can penalize owners who don't clear their sidewalks with tickets that start at $50 for a first offense and top out at $300, and they have been issued. Ticketing began eight hours after the storm ended, and since then 213 have been given. There are, however, 2,575 miles of city and state roads in Philadelphia and 21,950 intersections. The city doesn't record the number of sidewalks, a spokesman said, but simply walking a few blocks in the city reveals that the ticketing is insufficient to the scope of the problem.

Handing responsibility for clearing curb cuts and sidewalks to the city would require more manpower than Philadelphia could manage, considering the frequency of snow in the city, said Kelly Yemen, the city's Complete Streets director. (Editor's Note: This story has been updated to correct Yemen's title) She moved to Philadelphia in November and has been spearheading an effort to make the city safer and more welcoming for people on foot and bike. She admitted that the role snow plays in making sidewalks inhospitable hadn't been an action item in the Safe Streets plan until this week's storm. That may change,  she said.

"Generally, sidewalk conditions are something we're looking at," she said. "This is wrapped into just generally how are we caring for our sidewalks in any season."

Another wheelchair-using city man, Rodney Whitmore, said the lack of snow clearance at intersections forced him to travel in the street.

"The city needs to think about people's disabilities," he said. "We work hard, too."