These might be some of the coldest days of the year, but the warm sun has been causing havoc on the interstate highways during the late-morning rush hours lately.

Traffic has come to a near standstill on portions of the highways for eastbound motorists, causing some drivers to head to the exit ramps for fear that there are major accidents ahead.

But what's been happening in many cases has been a "highway shockwave," triggered by a bright sun low in the sky.

• See how traffic engineers describe the shockwave.

• Data Central index

