An unidentified person was struck and killed after exiting a moving car Monday afternoon on Interstate 290 eastbound near the Worcester-Auburn line, State Police said. The victim left a car while driving and was hit by a tractor-trailer around 5:10 p.m, State Police spokesman David Procopio said. The tractor-trailer driver stopped and remained on scene. The car continued about 600 feet before coming to rest against a guard rail, Procopio said. Procopio did not identify the victim. State Police shut down all three eastbound lanes as they investigated.Jeremy C. Fox can be reached at firstname.lastname@example.org. Follow him on Twitter @jeremycfox.