Volvo’s Radar-Based Occupant Alert System Aims to Extinguish Hot-Car Deaths

volvo-xc40-rechrage-2021-02-backseat-car-seat-check-interior 2021 Volvo XC40 Recharge | photo by Jennifer Geiger

According to the Department of Transportation, 935 children have been victims of hot-car deaths since 1998, and the tragedies have become more prevalent in recent years. The agency’s data show more than half of such deaths result from a child being forgotten in the vehicle, and more than half of the victims are children under 2 years old. To address the issue, Volvo has revealed a new interior radar system that monitors the entire vehicle to ensure young kids and pets aren’t left behind.

Related: Major Automaker Groups Agree to Add Rear-Seat Reminder to Cars by 2025

The new system uses a series of radar sensors in the overhead console, roof-mounted reading lamps and cargo area to detect even tiny movements throughout the car. While most rear-seat reminder systems alert the driver to check the rear seat when they turn off the engine, Volvo says the reminder is more effective after the driver attempts to lock the vehicle. With Volvo’s system, if the driver tries to lock the vehicle while a child or animal is detected inside, the lock function is disabled and an alert is displayed on the center console screen.

volvo-occupant-sensing-oem Volvo interior radar system | Manufacturer image

Some rear occupant alert systems available today use a combination of visual and audible alerts to notify the driver before and after they exit the vehicle, but Volvo’s is limited to the onscreen alert after the lock attempt to avoid warning fatigue, according to Volvo spokesperson Thomas Schultz.

“The system only alerts when the driver is attempting to lock the car,” Schultz confirmed in an email to “Alerting people of the presence of occupants when it’s likely they need it and avoiding excessive warnings — which can lead to alerts being ignored over time — is a fine balance. It is also difficult for a car to differentiate between a driver knowingly leaving the car for a few moments and one who has genuinely forgotten about a child or pet as they leave the car for a longer period.

“We have determined that the best time to alert the driver to occupants is when they’re going to lock the car: This is the point at which anyone inadvertently leaving a child or pet behind would need to be alerted, but reduces the risk of ‘warning fatigue’ that could arise from earlier warnings.”

In addition to activating the driver alert, the vehicle’s climate system will remain on when occupants are detected in order to reduce the risk of heatstroke or hypothermia so long as the vehicle’s battery has sufficient charge.

Currently, most occupant reminder systems are activated when a vehicle’s rear doors are opened at the start of the trip, but they don’t actively monitor the entire vehicle for passengers left behind. Volvo isn’t the first automaker to showcase the radar-based technology, however: Hyundai first launched its ultrasonic rear occupant alert in the 2020 Palisade three-row SUV, and Toyota has been testing a Cabin Awareness concept system in prototypes, though the system isn’t yet available in a production model.

Volvo will launch the interior radar system as a standard feature in its upcoming all-electric EX90 SUV, expected to be revealed Nov. 9. Future models will also offer the technology, but the automaker has not yet disclosed rollout plans.

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