MONTGOMERY COUNTY, Md. – Commuters heading into D.C. may be stuck in traffic Wednesday morning after a crash on I-270 in Montgomery County shut down all southbound lanes. Officials say the crash happened just before Exit 18 to MD-121 and that delays begin near MD-80. All southbound travel lanes have reopened as of 10 a.m., and the incident is contained to the right shoulder. However, delays remain.