PHILADELPHIA >> Several multi-car pileups — including one involving dozens of vehicles — in icy conditions on interstates in the Philadelphia area claimed at least four lives and injured dozens on Sunday as hundreds of crashes were reported across eastern Pennsylvania, authorities said.

The National Weather Service warned Sunday night that temperatures were expected to drop below freezing in and around Philadelphia overnight, and any remaining moisture on roadways and sidewalks could re-freeze. Drivers should be cautious, and conditions should improve as temperatures reach the 40s by midday Monday.

State police in Philadelphia said 31-year-old Eric Blau of Philadelphia was killed when he got out of his disabled vehicle on Interstate 76 at about 6:40 a.m. Sunday and was hit by another vehicle. Officials said his vehicle was one of the first struck in a series of crashes that involved about 60 vehicles on the icy roadway, injuring about 30 people, and closed the highway for much of the day.

Police in neighboring Delaware County said Thomas Brennan of Lansdale and Jason Anderson of Dover, Delaware were killed when their vehicles hit a tractor-trailer that that lost control due to ice in the southbound lanes of Interstate 476. Police said 15 vehicles were involved in that crash and an ensuing accident, which injured five more people, one seriously.

Both interstates are busy arteries serving communities west of the city. Officials said Interstate 95, a north-south highway through the area, was also closed early Sunday but had since reopened.

Police in Pike County in northeastern Pennsylvania said 34-year-old Pablo Pons of Honesdale was killed after his vehicle overturned on an icy road and he was thrown from it and hit by a commercial vehicle. A 12-year-old boy also thrown from the vehicle was critically injured.

Pennsylvania Department of Transportation spokesman Eugene Blaum called travel conditions “very hazardous” due to light rain falling onto cold surfaces, creating a sheet of ice.

“This is the worst type of winter precipitation to combat, because it can freeze instantly and it doesn’t need to be the whole pavement for vehicles crossing it to have problems,” Blaum said.

PennDOT had nearly 150 trucks out treating roadways before daybreak, when it became clear that conditions would be slippery, Blaum said.

Emergency dispatchers reported more than 80 calls for ice-related crashes in Northampton County, 100 in Lehigh County, 100 in Bucks County — some involving emergency vehicles –and more than 75 in Montgomery County.

Kaitlyn Maier, of Philadelphia, said she came upon the I-76 accident moments after it happened as she was driving with her boyfriend to her niece’s baptism, which she missed.

“Ten minutes before I was asking him, what is this? Rain, or what?” said Maier, who said she was 10 to 15 cars behind the wreck and saw smoke pouring from one vehicle. The line of crashed cars extended around a bend in front of her.

Maier said emergency responders directed her and other drivers to turn around on the highway and drive eastbound on the westbound side to the next exit.

Within the next several minutes, Maier saw two cars collide and two other accidents that had just happened. They decided to stop at a diner to wait until the roads cleared.

“I’ve driven through snow a lot, and this isn’t like anything I’ve ever driven in,” said Maier, who was raised in upstate New York. “We were stopped for a while on the side of the road. I was going less than 10 mph, but I had no control of my vehicle.”

The Delaware River Port Authority closed bridges linking Philadelphia and New Jersey during the morning while workers put down salt, but began reopening lanes by midmorning.

The Pennsylvania Turnpike closed between Morgantown and the Delaware River Bridge but reopened at noon with speed limits reduced to 45 mph.

The Southeastern Pennsylvania Transportation Authority canceled early bus service in Philadelphia but resumed service late in the morning.

Philadelphia International Airport reported some cancellations due to conditions.