Mazda's Blind Spot Monitoring: Standard Feature Or Optional Extra?

Mazda's Blind Spot Monitoring (BSM) system is an active safety technology that helps drivers stay alert and safe on the road. The BSM system uses radars mounted on the rear bumper to detect vehicles approaching from behind and adjacent lanes, alerting drivers through visual and auditory cues. While BSM is now considered an essential safety feature, its availability varies across Mazda models and trims, with some offering it as standard, others as an optional extra, and some not at all. This paragraph introduces the topic by providing an overview of Mazda's BSM system, its purpose, and its availability across different models.

Mazda BSM technology

Mazda's Blind Spot Monitoring system (BSM) is an active safety technology that acts as an extra set of eyes on the road for drivers. The BSM system uses radars mounted on the rear bumper to detect vehicles approaching from behind and in adjacent lanes. When a vehicle enters the driver's blind spot, an icon is displayed on the appropriate door mirror, and if the driver indicates to change lanes, the icon flashes and a warning beep sounds. This system is designed to alleviate the stress of changing lanes and help prevent accidents.

Mazda was the first Japanese automaker to include a blind spot monitoring system in its production cars, introducing it on the Mazda CX-9 Grand Touring in 2008. Since then, Mazda has offered BSM as an optional or standard feature on various trims and models of the Mazda 3 and Mazda CX-30. As of 2024, all Mazda vehicles are equipped with blind spot monitoring, regardless of trim level, as it is considered an essential safety feature.

The BSM system is designed to detect vehicles approaching from behind or in adjacent lanes, but it may not always be perfect. There are certain conditions under which the system may not detect a vehicle, such as if the vehicle is driving alongside at a similar speed, travelling in the opposite direction, or in an extremely wide adjacent lane. Additionally, the system may not detect small vehicles such as motorcycles or those with low heights.

The BSM system can be customized to suit the driver's preferences. For example, the alert volume can be adjusted or muted, and the system can be turned on or off using a switch on the dashboard. Overall, Mazda's BSM technology is an important safety feature that can help prevent accidents and improve the driving experience by providing drivers with additional information about their surroundings.

BSM limitations

Blind Spot Monitoring (BSM) is a safe driving system designed to reduce accident injuries and the burden of driving. While it is a useful feature, BSM has its limitations and drivers should not rely on it too heavily. Here are some of the limitations and conditions under which BSM may have limited functionality:

• Bad weather conditions: BSM may not function optimally in rain, snow, fog, or other adverse weather conditions.
• Proximity to other vehicles: If there is no approaching intention or if vehicles are driving parallel without a significant speed difference, BSM may not detect them as potential hazards.
• Road conditions: BSM may be limited on roads that are too spacious or too narrow, or on roads with continuous curves or uneven levels.
• Light sources: Street lamps, signal lights, or other light sources may interfere with the effectiveness of BSM.
• Vehicle speed: BSM in Mazda vehicles is designed to activate when the vehicle speed is 15 km/h or above. At slower speeds, the system may not function as intended.
• Vehicle size: Smaller vehicles, such as motorcycles or low-height vehicles, may not be detected by the system.
• Speed difference: If there is a high difference in speed with vehicles in the monitored area, BSM may not detect them accurately.

It is important to note that while BSM is a valuable safety feature, it should not be solely relied upon. Drivers should always remain attentive and practice safe driving habits, paying attention to their surroundings and using their best judgment.

Rear Cross Traffic Alert

The Rear Cross Traffic Alert (RCTA) system is a part of Mazda's Blind Spot Monitoring (BSM) system and uses the same radar sensors for vehicle detection. The RCTA is activated when the Mazda is put in reverse and can detect vehicles that might be crossing your rearward path, such as when you're backing out of a parking space or driveway. The RCTA system is designed to assist the driver in checking the area to the rear of the vehicle on both sides while the vehicle is reversing by alerting the driver to the presence of vehicles approaching the rear of the vehicle.

The RCTA system detects vehicles approaching from the rear left and right sides of the vehicle, and the rear of the vehicle while the vehicle is being reversed out of a parking space, and notifies the driver of possible danger using the Blind Spot Monitoring (BSM) warning indicator lights and the warning buzzer. The system provides both a visual and audible alert when a vehicle is detected. The RCTA warning indication in the rearview monitor also synchronizes with the BSM warning indicator light on the door mirrors.

The RCTA system operates when the shift lever (manual transaxle) or the selector lever (automatic transaxle) is shifted to the reverse (R) position. If there is a possibility of a collision with an approaching vehicle, the BSM warning indicator lights flash and the warning beep is activated simultaneously. It is important to note that the system is only designed to assist the driver in checking for vehicles at the rear and should not replace the driver's responsibility to check the rear before reversing.

There are certain limitations to the RCTA system. For example, the BSM warning indicator lights may not flash or may be delayed even though a vehicle is behind the Mazda. Additionally, under certain conditions, the radar sensors may not be able to detect target objects or it may be difficult to detect them. These conditions include when the vehicle speed when reversing is about 10 km/h (6 mph) or faster, or when the radar sensor detection area is obstructed by a nearby wall or parked vehicle.

BSM sensors

Mazda's Blind Spot Monitoring system (BSM) uses radar sensors mounted on the rear bumper to detect vehicles approaching from behind and in adjacent lanes. These sensors are positioned on each corner of the car, with one on each side of the rear bumper. The system provides an extra set of eyes on the road, alerting drivers to the presence of vehicles in their blind spots.

The BSM system is designed to help drivers when changing lanes or reversing out of parking spaces. When a vehicle enters the driver's blind spot, the system displays an icon in the appropriate door mirror. If the driver indicates to change lanes while a vehicle is in the blind spot, the icon flashes and a warning beep sounds. This alerts the driver to the potential hazard, allowing them to make a safer lane change decision.

While the BSM system is generally reliable, it may not detect vehicles in certain situations. For example, if a vehicle is driving alongside the Mazda at a similar speed, or if the vehicle is in an extremely wide adjacent lane, the BSM system may not provide an alert. Additionally, the system may not detect small vehicles such as motorcycles or those with low heights.

The BSM system has evolved over the years, with Mazda introducing it as an optional feature in 2012 for select models and trims. Over time, Mazda expanded the availability of BSM, and in 2024, all Mazda cars were equipped with BSM as a standard feature, regardless of the trim level.

BSM accuracy

The accuracy of Mazda's Blind Spot Monitoring (BSM) system is dependent on several factors, including the speed of the monitored vehicle, the relative speed difference, and the size of the vehicle. The BSM system uses radar sensors mounted on the rear bumper to detect vehicles approaching from behind and in adjacent lanes. While the system is designed to provide an extra set of eyes on the road, there are certain conditions under which the BSM system may not detect a vehicle in the blind spot.

For example, if the vehicle within the detection area is not approaching the Mazda vehicle, or if it is travelling in the opposite direction, the BSM system may not alert the driver. Additionally, if the vehicle is travelling at a similar speed or if it is in an extremely wide adjacent lane, the BSM system may not register it as a potential hazard. The system also has limitations in detecting small vehicles like motorcycles or those with a very low height.

The BSM system's accuracy can also be affected by external factors such as weather and road conditions. In complex environments, the system may struggle with a high false alarm rate or a missed alarm rate. However, Mazda has likely taken steps to improve the accuracy of their BSM system, as it is now considered an essential safety feature.

Aftermarket blind spot monitoring systems are also available, but their accuracy may vary. The most affordable options may have limited functionality and accuracy, while more advanced systems with better algorithms and sensor accuracy can cost more than $500.

Frequently asked questions