All new vehicles built for sale in the United States, as of September 2008, must be fitted with a T.P.M.S. (tire pressure monitoring system). Maintaining proper tire pressure for a vehicle is an important factor in how much load its tires can carry. To help ensure driver's safety, some states require the T.P.M.S. to be operating in order to pass their vehicle inspection tests. Currently Hawaii, Rhode Island, Vermont and West Virginia require a functioning T.P.M.S. to pass inspections. Regardless of where you live, it is best to have a tire pressure monitoring system that works and Tire Rack offers many options for your convenience.