Medical Definition of adhesive. 1: an adhesive substance; especially : a substance (as glue, starch, paste, or mucilage) that bonds two materials together by adhering to the surface of each.
The sensors physically measure the tire pressure in each tire and report it to the vehicle's instrument cluster or a corresponding monitor. Some units also measure and alert temperatures of the tire as well. These systems can identify under-inflation in any combination, be it one tire or all, simultaneously.
The direct TPMS is used more often in the United States. The sensors are located in the tire pressure valve, which acts as an antenna, or are wrapped around the rim of the wheel with a band clamp. These devices transmit the information to an on-board computer.