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. The system is also sometimes referred to as a tire-pressure indication system (TPIS). These systems report real-time tire-pressure information to the driver of the vehicle, either via a gauge, a pictogram display, or a simple low-pressure warning light.

The federal government has mandated that all new passenger cars, multipurpose vehicles, trucks & buses weighing 10,000 pounds or less be equipped with tire-pressure monitoring systems (TPMS). The systems must indicate when one or more tires have lost 25% of their recommended inflation pressure, allowing consumers to avoid the resulting unsafe driving conditions. The rule is being phased in, with 20% of the affected vehicles required to comply by model-year 2006, 70% by 2007 and 100% by model-year 2008.