Philadelphia's streets, many of them left unplowed until Wednesday afternoon, became more manageable yesterday - helped along by bright sun and a steady wind that helped clear and dry some streets.

By midday, most major arteries through Philadelphia had been cleared though many still had a median of slushy ice left by plows that separated lanes of traffic.

On-street parking often was like driving on a washboard, even on major routes such as Broad Street, because parked cars had prevented plows from clearing snow from the parking lanes near the curb.

City streets commissioner Clarena I.W. Tolson said city crews would work through last night and into today to clear the remainder of the 2,040 miles of street the city maintains.

Tolson said the job had been made more difficult by the below-freezing temperatures that made the slush stone-hard by morning.

"The temperature has definitely been a challenge," Tolson added. "We've had to use a lot more chemical on the streets."

According to the National Weather Service, those temperatures are not likely to moderate much during the next few days. The good news: only a slight chance of snow tomorrow night through Sunday.

Tolson reiterated that the storm's nature made removal difficult.

"We had snow but we only got an inch and you can't use a snow plow when you have an inch or less," Tolson said.

Tolson said crews salted or brined streets but the snow was followed by a day of sleet and freezing rain. The three, combined with the salt and chemical, created a "frothy mix" that then froze overnight.

"This was a very unusual storm," Tolson said, noting that Gov. Rendell yesterday afternoon declared a statewide state of emergency to enable road and emergency crews to respond to the crisis on Interstate 78 and other state highways.

A 50-mile stretch of Interstate 78 remained closed yesterday from Lebanon to Lehigh Counties as police and road crews worked to clear the highway of a line of vehicles trapped on the icy, hilly expressway and unable to move.

Some of the motorists had been trapped in their cars for more than a day.

Philadelphia's situation paled in comparison.

The only problem noted by Philadelphia police yesterday was complaints about sheets of ice that flew from the flat roofs of trucks and then crashed onto the roadway in front of - or on - drivers following behind.

Contact staff writer Joseph A. Slobodzian at 215-854-2985 or jslobodzian@phillynews.com.