In Pennsylvania, driving in the winter is an obstacle course.

You steer right to swerve around a pothole.You jerk left, just missing another, larger hole that is waiting to swallow a tire.This back and forth technique is becoming the norm as potholes are popping up quicker than the Pennsylvania Department of Transportation can patch them.But how do potholes form?According to a diagram supplied by Ron Young, district press officer for PennDOT Engineering District 5, potholes begin after snow or rain seeps into the soil below the road surface.When temperatures drop to below freezing, the moisture freezes, causing the ground to expand and push the pavement up.As the temperature rises, the ground returns to its normal level, but the pavement that was pushed up remains raised, creating a gap between pavement and ground.When a vehicle drives over this portion of pavement, it cracks and falls into the gap, thus creating a pothole.