Editorial Feature

Automotive Sensors: Blind Spot Sensor Technology


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All drivers need to be aware of the so-called “blind spot” in their field of vision, in which an area close to the vehicle and uncovered by mirrors is invisible unless they can rotate their body to look out of the driver-side window.

Blind spots occur in all large vehicles including trucks, cars, aircraft and motorboats. Direct blind spots vary by vehicle, and drivers especially should be familiar with which around their car are not covered by mirrors or otherwise obscured from their vision.

Trucks have a large number of invisible areas when compared to other passenger vehicles. However, blind spot accidents can be minimized with the incorporation of a vehicle-based sensor, a blind spot monitor that detects other vehicles or objects at the sides and rear of the driver. This sensor alerts the driver through visual or audible warnings.

The following video discusses the introduction of a blind spot detection system by Autol. The sensor device is made up of three segments: the control unit, the detection unit, and the alert bar.

Blind Spot Detection System for vehicles - SEMA 2010

An animated demonstration of the blind spot detection system is a great example of how this device works when on the road.

Blind spot detection


A significant proportion of automotive accidents occur due to the driver's carelessness with blind spots. Although a number of methods are available for assisting drivers, wide-angle glasses and rear mirrors are the simplest methods that help drivers overcome the blind spot.

However, a major limitation of these methods is the need for human assistance. Another approach involves the use of sonar- or radar-based sensors that collect and process range information for predicting collisions.

In 2009, Mahapatra R.P and colleagues from SRM University, Chennai, India, proposed a panoramic sensor-based automated vehicle monitoring system that captures the images of objects with the help of a rotating camera and processes them. These high-resolution panoramic images are unwrapped to obtain a complete three-dimensional image by which the distance between the vehicle and object can be determined.

Coverage control of blind spots is one of the major challenges involved in the application of wireless sensor networks. Jin and colleagues from Northeastern University, Shenyang, China investigated the coverage control problem for hybrid networks comprising static and mobile sensors in 2009. Results of simulation showed that the proposed mechanism is feasible and effective.

Sotelo and colleagues proposed a vision-based blind spot detection system in the University of Alcalá, Spain, in 2008, for intelligent vehicle applications. The lateral mirror of a car is mounted with a camera to visually detect the blind spots.

The detection is carried out through computer vision techniques such as optical flow and double-stage data clustering techniques.

The proposed system can predict the blind spot located at a distance of 20 m from the vehicle and alerts the driver about the presence of obstacles or other vehicles in the blind spot area. Experimental results showed that the system has a detection rate of 99% and low false positive rates.

Current Applications

Blindspot detectors are used for detecting bystanders, obstacles and other automobiles for protection against mishaps such as accidents and collisions with automobiles or obstacles. They are also used for cross-traffic warning to alert a driver of what is approaching from the left and right sides while stepping out of the car.

Currently, a number of aftermarket blind spot sensor systems are available from a wide range of manufacturers. Blind spot sensor technology is also routinely included in new cars, especially electric vehicles such as the Nissan Leaf.

Future Developments

Every year, a large number of accidents take place due to blind spots. Although the mortality rate of these accidents is just 1% which is low compared to other accidents, the extent of injury and property damage is high. Therefore, lane-change blind-spot accidents remain a cause of great concern.

According to the U.S Department of Transportation, highway congestion resulting from more vehicles on the same lane is the prime cause of blind spot accidents. Radar systems are a suitable technological solution.

In 2007, Valeo Raytheon Systems Inc., one of the largest automotive suppliers in the world, developed a lane-change assistance system consisting of radar sensors. These sensors continuously monitor the velocity and direction of the vehicle to obtain a digital picture of the vehicle's environment. The warning indicator is switched on when the vehicle approaches the blind spot. The system also emits an audio alarm to give an additional warning.

Similarly, the blind-spot detection device developed by Advanced Technology Products of Toronto, Canada, employs a patented passive infrared sensor technology that can sense thermal energy released from the tires of the vehicle while moving.

The temperature difference is used for turning on the red light to warn the driver. Most of the automobile manufacturers consider employing radar-based sensors as these radars cover a wide area from the vehicle's side to the rear and have the potential to differentiate mobile and stationary objects.

Sources and Further Reading

  • Mahapatra RP, Kumar KV. Panoramic sensor based blind spot accident prevention system. World Academy of Science, Engineering and Technology. 2009;25:915-921.
  • In Search of the Ideal Blind-Spot Detection System – Frost & Sullivan
  • Jin L, et al. Research on the discovery of blind spots in wireless sensor networks based on voronoi diagram. This paper appeared in Hybrid Intelligent Systems. HIS '09. 2009;2:209-214.
  • Sotelo MA and Barriga J. Blind spot detection using vision for automotive applications. Journal of Zhejiang University Science A. 2008;9(10):1369-1372.

This article was updated on 13th February, 2020.


  1. Diehard65 . Diehard65 . United States says:

    I have been driving a 2011 Dodge Charger, equipped with a blind spot alarming system, for over 2 years. I consider myself a fairly careful driver but done the less, I have to say nothing beats the speed  of an audible alarm when that turn signal is touched. (I have the visual as well.)

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