Traffic crawls along the Capital Beltway during rush hour, in Greenbelt, Md., Tuesday, Aug. 25, 2015. (AP Photo/Jose Luis Magana) ** FILE **
In this May 23, 2014 file photo, traffic moves on the Interstate 495, the Capital Beltway, in Hyattsville, Md., outside Washington. (AP Photo/Carolyn Kaster, File) **FILE**