(Portland, OR) -- Several police agencies are focusing on seat belt use during the Click It, Or Ticket enforcement that's going on through Sunday June 2nd. The National Highway Traffic Safety Administration helps fund overtime for the officers who watch for drivers wearing seat belts. About half of the drivers who are killed in crashes weren't wearing seat belts. In Oregon, children are required to be in rear-facing safety seats until they are at least two years old. Children older than two need to ride in a car seat with a harness or booster seat until they're four-feet nine-inches in height.