In this image from PennDOT via FoxTV, more than 20 cars are piled up on I-76 in Philadelphia after freezing rain on Sunday, Jan. 18, 2015. Slick roads caused a number of crashes, including collisions that also closed parts of Interstates 95 and 476 in and around Philadelphia. (AP Photo/PennDOT via FoxTV)
In this image from PennDOT via FoxTV, more than 20 cars are piled up on I-76 in Philadelphia after freezing rain on Sunday, Jan. 18, 2015. Slick roads caused a number of crashes, including collisions that also closed parts of Interstates 95 and 476 in and around Philadelphia. (AP Photo/PennDOT via FoxTV) AP
In this image from PennDOT via FoxTV, more than 20 cars are piled up on I-76 in Philadelphia after freezing rain on Sunday, Jan. 18, 2015. Slick roads caused a number of crashes, including collisions that also closed parts of Interstates 95 and 476 in and around Philadelphia. (AP Photo/PennDOT via FoxTV) AP