The Contact Area Information Sensing (CAIS) system includes a sensor on the tire's internal wall that monitors its interaction with the road surface and informs the driver accordingly. In development since 2011, the CAIS is finally ready for commercial applications.
Bridgestone unveiled this technology at the 2011 Frankfurt Auto Show, with a first version that used a strain sensor to calculate the load and side forces acting on the tire. The CAIS 2 version followed with a new acceleration sensor that could identify the road surface conditions, and in 2014 the CAIS 3 was introduced, having evolved into a system that could also monitor the tire's wear.
The latest release from Bridgestone's Japanese headquarters announces the commercialization of the CAIS 2 setup.
Aimed at car and truck tires, this system relies on an acceleration sensor placed on the inside wall of the tire, powered by a proprietary electromagnetic generator. Its task is to monitor the high frequency vibrations of the tire and transmit them wirelessly to the CAIS central module that's housed inside the car.
There the data are compiled and translated to the actual road surface conditions, distinguished in seven different states: dry, semi-dry, wet, slush, fresh snow, compacted snow, ice. This information is then conveyed to the driver via a digital screen, providing a vital understanding of the road conditions in real time.
For Bridgestone this is just the first step, as future plans include sharing this information to vehicles following behind. This of course is not entirely up to the Japanese company, requiring a broader communication infrastructure that includes both the road and the vehicles on it. Such Intelligent Transportation Systems have been in development for several years in Japan, Europe and USA, and Bridgestone appears to have a head start over its competition.
With plans for commercial application of the CAIS 3 system in the near future, coupled with the widely used air pressure sensors, Bridgestone could soon have tires on offer that communicate to the driver comprehensive information on every aspect of the tire's interaction with the road: air pressure, tread wear and road conditions.
Source: Bridgestone (in Japanese)