Checking the rearview mirror, looking over the shoulder, and only then changing lanes. That’s the mantra every driver learns in driving school. However, in dynamic traffic, a moment of inattention or a vehicle that “hid” exactly where we do not see it, in the so-called blind spot, can lead to a serious accident.
This is exactly where one of the most valued technologies to help the driver – the blind spot monitoring system (Blind Spot Monitoring – BSM) comes into play. Once reserved only for premium models, today it is increasingly available, but often comes with a hefty surcharge. With that in mind, the question is, is the BSM really a necessary guardian angel or just another expensive addition to the equipment list?
How does BSM work?
The basic task of the blind spot monitoring system is simple, to monitor the area next to and slightly behind the vehicle that the driver cannot see either in the rearview mirrors or with peripheral vision. To achieve this, the system relies on sensors, usually radar, hidden in the corners of the rear bumper. These sensors constantly emit radio waves and analyze their return, recognizing objects such as cars, trucks, and increasingly motorcycles that enter the critical zone. Although radars are the most common and reliable solution because they work flawlessly in almost all weather conditions and at high speeds, some manufacturers also use ultrasonic sensors (similar to parking sensors) that are more effective at lower, city speeds or even cameras.
When the system detects a vehicle in the blind spot, it warns the driver in the most intuitive way possible, which is usually by turning on a small indicator light, usually orange or yellow, in the housing of the side mirror or on the A-pillar. This passive warning is discreet and non-disruptive. However, if the driver ignores the light and activates the turn signal, the system will respond with a different, more active warning level. This is most often a sound signal, but it can also be a vibration of the steering wheel.
The most advanced systems go one step further. If the driver nevertheless starts to change lanes, the “active” system can intervene independently by turning the steering wheel slightly or applying the brakes on the opposite wheels to return the vehicle to a safe position within the lanes.
How effective is BSM really?
A subjective sense of security is one thing, but real efficiency is measured by statistics. Research is relentless and confirms that BSM is one of the most effective security technologies today. According to a comprehensive study by the US Institute of Highway Safety (IIHS), vehicles equipped with a blind spot monitoring system have a 14 percent lower crash rate when changing lanes. Even more interesting is the fact that the number of collisions with injured persons decreases by as much as 23 percent.
Translated into real numbers, it is estimated that in the US alone, if every vehicle were equipped with this system, around 50,000 crashes and almost 16,000 injuries would be prevented annually. These are tens of thousands of people who have avoided accidents thanks to a pair of radar eyes on the back of their car. It is precisely because of these results that safety agencies such as Euro NCAP give additional points to vehicles that offer BSM as standard equipment, putting pressure on manufacturers to make it standard.
Limitations and pitfalls of the system
Despite its proven effectiveness, BSM is not omniscient and has its limitations. The greatest danger lies in the driver’s psychology, which is excessive reliance on technology. Drivers can get so used to the light signal in the rearview mirror that they completely stop physically checking the blind spot by looking over their shoulder. This can be dangerous if the system fails or fails to recognize the threat.
Sensors covered in mud, snow or ice can temporarily stop working, and most systems only activate above a certain speed, usually around 30 km/h, which means they are not always helpful in heavy city traffic. Also, the systems sometimes have a harder time detecting smaller vehicles like motorcycles and bicycles due to their narrower silhouettes. Research shows that the system can take up to 26 percent longer to spot a motorcycle compared to a car.
Why is it not standard equipment?
If the technology is so effective, why don’t we still find it as standard equipment in all cars, like airbags? The answer lies in the manufacturer’s pricing policy. BSM is rarely offered as a standalone option. Instead, manufacturers “package” it together with other, often less essential, equipment items (like tinted windows or cruise control) into more expensive packages that can cost from 500 to 1,500 euros.
Analysis by Consumer Reports showed that buyers often have to upgrade to a higher, more expensive equipment package just to get this key safety feature, which can increase the total price of the vehicle by several thousand euros. Paradoxically, some more affordable cars, such as the Hyundai Elantra or the Nissan Sentra for the American market, offer BSM as standard on all trim levels, while in much more expensive SUVs it is still an expensive extra.
In conclusion, the blind spot monitoring system is not just another marketing gimmick. It is a technology that has been proven to reduce the number of accidents and save lives. Although it has its limitations and manufacturers often charge unfairly for its installation, its value is unquestionable. Trends show that, under the pressure of safety regulations and increasing customer awareness, BSM will slowly but surely become the standard, just as ABS and ESP have become. Until then, if you’re buying a new or newer used car, paying extra for this system is one of the smartest investments you can make in your own safety.