For increased safety and economic reasons in the world, motor vehicle manufacturers are beginning to install TPMS (Tire Pressure Monitoring System). There are two types of TPMS in the market;​ one is a direct TPMS using pressure sensor, the other is an indirect TPMS using the wheel speed sensor signals from ABS.

Most indirect TPMS are unable to detect a 4-tire simultaneous deflation condition because indirect TPMS are based on the principle that the 4-tire speed signals are compared with each other. However, the SRI Group (Sumitomo Rubber Industries, Ltd.) has developed an indirect TPMS which can detect a 4-tire simultaneous deflation based on a newly developed principle using wheel speed signals from the ABS.