What is a blind spot monitor?

  • How does a blind spot monitor work?
  • What are the benefits of it?
  • Parkers explains the tech
  • How does a blind spot monitor work?
  • What are the benefits of it?
  • Parkers explains the tech

A blind spot monitor warns the driver if another vehicle is positioned in their "blind spot" - that area over the driver's shoulder, often obscured by metalwork - usually by a visual or audible alert. Active blind spot monitors can, in certain circumstances, take things further and tell the car to take evasive action in the event of a predicted danger.

How does a blind spot monitor work?

Much like adaptive cruise control (ACC), the car beams out radar waves in order to detect other vehicles in the driver’s blind spot. If one is detected, the car will alert the driver using a visual or audible signal - and some may even issue a haptic alert, by vibrating the steering wheel for instance. Alerts will often be heightened if the driver has activated the indicator on the side of the hidden vehicle, suggesting they're about to move into danger. 

Do I need it?

If you frequently travel on motorways, a blind spot monitor is a valuable piece of equipment and could save your life. Those who do most of their driving in town may still find it useful when spotting cyclists, however.

Found on

Initially introduced on Volvo cars, blind spot monitor systems are now available on a wide range of vehicles such as the Ford Focus, Volkswagen Passat and Mercedes C-Class.

Also known as

Active blind spot assist, side assist.

Looking for more jargon-busting motoring meanings? Head over to our Parkers Car Glossary page and take a look at our other definitions

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