If 18 year old owns car and owns own car insurance policy and has an accident that exceeds the value of the policy can parents of 18 year old be held liable if 18 year old lives with them?

IT DEPENDS ON THE STATE HE/SHE LIVES IN. SOME STATES ARE NO-FAULT AND THEY MAKE IT DIFFICULT FOR LITAGATION. IF THE 18 YEAR OLD IS A DEPENDANT SUPPORTED BY THE PARENTS i.e. A COLLEGE STUDENT THEN THEY COULD BE IN TROUBLE.