Schrader-Bridgeport is the industry leader in direct Tire Pressure Monitoring Systems. Direct TPM systems use pressure sensors inside each tire to transmit data to a dashboard display alerting drivers to tire pressure issues.

Congress passed the Transportation Recall Enhancement, Accountability and Documentations Act, also called the TREAD Act, in 2000 in response to a major recall of defective tires that created unsafe driving conditions.

The TREAD Act mandates that new vehicles less than 10,000 pounds gross vehicle weight, sold in the United States, be equipped with tire pressure monitoring systems, or TPMS, beginning with the 2006 model year. TPMS systems alert drivers when the pressure in a tire falls more than 25 percent below the manufacturer’s recommended tire pressure. The TREAD Act affects passenger cars, light trucks and buses. Light-duty vehicles with dual-rear axles are excluded.

Indirect TPMS systems use the vehicle’s ABS system to calculate the difference in tire diameters and approximate tire pressure.

Direct TPMS systems include small sensors that are installed inside the tires. These sensors monitor tire pressure and continually relay this information, via radio signals, to the vehicle’s electronic control unit (ECU). If tire pressure falls below required limits, a warning light on the instrument panel alerts the driver about the problem.

The TREAD Act requires vehicle manufacturers to equip 20 percent of their 2006 model year vehicles with TPMS. The number increases to 70 percent of 2007 model vehicles, and to 100 percent of all 2008 model vehicles.

System Performance Requirements
The TREAD Act outlines a number of specific TPMS performance requirements:

• New vehicles must be equipped with sensors that monitor tire pressure in all four tires. Monitoring the spare is not required.
  
• The TPMS system must operate when the vehicle ignition is on and warn when tires are under-inflated by 25 percent or more.
  
• The TPMS system must alert the driver when there is a system malfunction.
  
• The TPMS warning light must stay on until the tire is inflated to the proper pressure or the system malfunction is corrected.
  
• A “bulb check” of the warning light on the instrument panel must occur whenever the ignition is turned on.
  
• Vehicle owner’s manuals must contain warnings about potential incompatible replacement tires for the vehicle.

Click on question topics for answers to frequently asked TPMS questions.