Automobiles have been equipped with sensors for many years. The ubiquitous devices warn motorists when they're vehicle is low on fuel or when a door is slightly ajar.

But, today, sensors connected with safety applications proliferate on vehicles. For instance, sensors play an important role in electronic stability control (wheel-speed, gyro and braking sensors) and lane departure warning and blind-spot detection systems (radar, infrared and optical sensors).

"Active safety systems are driving increased sensor use," says Robert LaGuerra, senior automotive industry analyst at ABI Research (Oyster Bay, NY). "Safety sells. It is becoming one of the biggest markets in the automotive industry. And the economic implications of road safety mean that governments are involved."

LaGuerra is the author of a new study on automotive sensors that tracks future demand to 2012. It discusses many of the safety applications that employ sensor technologies; identifies market drivers; and offers detailed profiles of the major industry players.

According to LaGuerra, blind-spot detection will be a key growth segment. He believes that radar will ultimately prevail over competing infrared and optical technologies. For bumper-mounted close-range obstacle detection, he cites ultrasonics as the most popular technology.

But LaGuerra warns that sensors are not "one size fits all." Different sensors may address the same task, but not all perform equally under all conditions, he points out. So, many future safety systems will feature combinations of multiple sensing technologies. For instance, radar and optics will be used for forward-viewing applications.

While sensor technology is improving, LaGuerra says several factors may slow their evolution, such as the auto industry's long development cycle and a lack of standardization. "These factors, which differ greatly with the difficulty of the task and the sophistication of the system, must weave their way through a complex web of industry players: OEMs, system designers and sensor manufacturers," explains LaGuerra.