Blind Spot Monitor
Blind spot monitoring, BSM, or a blind spot information system, depending on the term used by the vehicle manufacturer, is a safety feature which was first introduced by Volvo over 10 years ago. Blind spots can be a major cause of high speed car accidents simply because when a car changes lane on a motorway or dual carriageway any adjacent vehicles could no longer be seen in the rear view or side mirrors, and may be obscured by the A-pillars. Therefore, blind spot monitoring is most effective when your car is passing another vehicle, being passed, or when you’re preparing to make a lane change.
How does it work?
Some car manufacturers use cameras although the majority of blind spot monitoring systems utilise radar sensors which are usually located under the rear bumper or wing mirrors. They monitor the areas behind and next to your car. The detection area covers approximately one lane width on both sides of the vehicle, and extends from the side view mirrors to approximately 10 feet beyond the rear bumper.
A visual alert, which is usually yellow in colour, will flash in the wing mirror on the relevant side of the car to alert the driver that a vehicle is in the blind spot. It will then go out when the passing car is either alongside you or is in front of your vehicle.
Blind spot monitoring systems do not tend to be configured to detect two-wheeled vehicles on the road such as motorcycles and bicycles, so extra care is needed when passing them. The same degree of attention also of course applies even if you don’t have the technology fitted to your car.
This technology is designed to minimise the risk of accidents rather than replacing the need for the driver to remain vigilant whilst driving, for this reason you should never relay solely on any technology but instead see it as an extra level of protection.