A tire pressure monitoring system (TPMS) is an electronic system designed to monitor the air pressure inside the pneumatic tires on various types of vehicles. This system reports real-time tire pressure information to the driver of the vehicle, either via a gauge, a LED display or a warning light. Maintaining proper tire pressure is critical for driver safety as well as maximizing tire tread life.
In October 2000, United States legislation enacted the TREAD Act (Transportation Recall Enhancement, Accountability and Documentation). This Act mandated the use of TPMS in all light motor vehicles (under 10,000 pounds), to help alert drivers to severe tire under-inflation. This act affects all light motor vehicles sold after September 1, 2007.
Although vehicle manufacturers are now required to install TPMS sensors in new vehicles, there has been some confusion on whether or not drivers are required to keep their TPMS active. Although most states have not mandated the TPMS remain active, there are at least four states that currently require vehicles manufactured after October 2007 to have properly functioning tire pressure monitoring systems. These states include Hawaii, Rhode Island, Vermont and West Virginia and verification of proper TPMS function is part of the annual vehicle inspection.
Take a look at "State TPMS Regulations" to help confirm restrictions in your area.