Automotive Electronics Banner

Blind Spot Detection

Basic Description
Blindspot Illustration

A person seated in the driver's seat of a typical car or truck depends on the rear view mirror and two side mirrors to see vehicles approaching from behind. However, vehicles or other objects on either side and slightly behind a car may be in an area that is outside the field of view of the these mirrors. This region is called the vehicle's blind spot. Driver's education classes emphasize the importance of checking for vehicles in the blind spot before attempting to make a lane change. Nevertheless, hundreds of thousands of collisions occur every year during lane changes.

Blind spot detectors use radar or image sensors to monitor a vehicle's blind spots and alert the driver when other vehicles are present. The alert indication is normally a yellow or red light located in or near the side mirrors that illuminates when a vehicle enters the blind spot associated with that particular side of the vehicle. Some models will provide an additional haptic warning that vibrates the driver's seat and/or steering wheel should they use the turn signals to indicate their intention to change lanes even though there is a vehicle in the blind spot.

With the 2011 model year, Infiniti introduced two models offering a feature called "Blind Spot Intervention". In addition to warning the driver about a vehicle in the blind spot, this system actually helps to prevent the car from changing lanes when a collision is likely to occur. The system applies mild braking to the wheels on the opposite side of the vehicle to pull the vehicle back to its original lane when it determines that changing lanes is likely to cause a collision with a vehicle in the blind spot.

Other Blind Spot Detection Methods

Bosch's "Side View Assist" uses ultrasonic sensors for blind spot detection.

Multi-radius mirrors having a 40-degree field of view have been a popular option for consumers in Europe and Japan for more than 20 years. But in the US, this cannot be the solution, since government regulations permit only flat mirrors, having a 15-degree field of view.

A different blind-spot detection device has been developed by Advanced Technology Products of Toronto, Ontario. The system uses a patented passive infrared sensor technology, which the company claims can sense thermal energy radiating from the tires of a moving vehicle. This temperature difference is used to trigger a flashing red light to warn the driver of the hazard.

Michigan-based Magna Donnelly Corp. has developed panoramic vision displays involving three cameras, which can give an image of both sides and of the back of the vehicle, covering a 70-degree field of view with almost no blind spots. The three cameras replace the exterior and interior rear-view mirrors.

Radar and/or image sensor, vehicle speed sensor
Light or display (usually in side mirrors) sound alert, brakes, haptic warning in the seats or steering wheel.
Data Communications
Some units are self-contained (i.e. no data communication). Others may use CAN or LIN buses.
Bosch, Continental, Delphi, LaneFX, Smartmicro, SMR, TRW, Valeo, Xiamen Autostar
For More Information
[1] In Search of the Ideal Blind-Spot Detection System, Frost & Sullivan, June 2004.
[2] The New Volvo S80's Blind Spot Detector, David Thomas, Kicking Tires Blog,, Feb. 16, 2007.
[3] Side Blind Spot Detection: DigInfo, YouTube, June 2007.
[4] Blind Spot (vehicle), Wikipedia.
[5] Blind Spot Warning (BSW) System/Blind Spot Intervention" (BSI) System, YouTube, Mar. 2010.
[6] Chrysler Blind Spot Protection Demo in Parking Lot, YouTube, June 26, 2008.
[7] Autostar Blind Spot Assist Video, YouTube, Mar. 11, 2009.
[8] Blind Spot Detection System Detects Human Body, Christoph Hammerschmidt, EE Times Europe, May 25, 2010.
[9] Blind Spot Assist Demonstration, YouTube, July 27, 2010.
[10] Blind Spot Detection System - SEMA 2010,
[11] Blind Spot Detection Systems In 25% of New Cars by 2016, ABI Research, Mar. 2011.
[12] 2013 Toyota Rav4 | Blind Spot Monitor, YouTube, Dec. 13, 2012.