A four-vehicle crash on Interstate 495 northbound in Claymont left one person dead. The crash north of the Philadelphia Pike interchange happened about 11 a.m. and involved a tractor trailer. A Delaware State Police helicopter and several New Castle County paramedic units joined with Claymont firefighters to rescue and treat the injured. The state police Collision Reconstruction Unit has been called out to the scene and the northbound lanes of the interstate are expected to remain closed for several hours.