A tire-pressure monitoring system (TPMS) monitors the air pressure inside the pneumatic tires on vehicles.[1] A TPMS reports real-time tire-pressure information to the driver, using either a gauge, a pictogram display, or a simple low-pressure warning light. TPMS can be divided into two different types – direct (dTPMS) and indirect (iTPMS).
TPMS are installed either when the vehicle is made or after the vehicle is put to use. The goal of a TPMS is avoiding traffic accidents, poor fuel economy, and increased tire wear due to under-inflated tires through early recognition of a hazardous state of the tires. This functionality first appeared in luxury vehicles in Europe in the 1980s, while mass-market adoption followed the USA passing the 2000 TREAD Act after the Firestone and Ford tire controversy.
Mandates for TPMS technology in new cars have continued to proliferate in the 21st century in Russia, the EU, Japan, South Korea and many other Asian countries. From November 2014 TPMS was mandatory for new vehicles in the European Union; in a survey carried out between November 2016 and August 2017, 54% of passenger cars in Sweden, Germany, and Spain were found not to have TPMS, a figure believed to be an under-estimate.[2]
Aftermarket valve cap-based dTPMS systems, which require a smartphone and an app or portable display unit, are also available for bicycles,[3] automobiles, and trailers.[4]