NHTSA urged to require rear seat belt warning systems

December 5, 2019

Federal regulators should amend vehicle safety standards to require a visual display that alerts the driver when passengers in the rear seats are not wearing their seat belts, the Insurance Institute for Highway Safety and the Highway Loss Data Institute said in a recent regulatory comment.

The National Highway Traffic Safety Administration (NHTSA) requested comments on whether to require rear seat belt reminders in a possible update to vehicle safety standards.

Consumers want these reminders, IIHS research shows. However, detecting unbelted passengers in the back can be complicated, David Kidd, HLDI senior research scientist, wrote in the comment.

Without a complex detection system, a toddler properly secured in a child seat could trigger a false alarm, for example. That makes an audible alert impractical for now. A display-based system would allow drivers to remind passengers to buckle up, while minimizing the aggravation caused by false warnings.

The rear-seat system should also include an audible and visual warning when rear seat belts are unfastened while the vehicle is in motion — an unlikely scenario for false alarms.

In addition, NHTSA should update its standards for safety belt reminders in the front of the vehicle, Kidd wrote.

The current standard applies only to the driver’s seat. It requires a 4-8-second continuous or intermittent warning sound and a continuous or flashing warning light or text alert that lasts at least 60 seconds. Both warnings must be triggered when the ignition is switched on and the driver’s lap belt is not in use.

However, IIHS research shows that audible warnings that last at least 90 seconds increase the seat belt use of drivers who do not routinely use a seat belt by more than a third (see “Belt reminders can be just as effective as interlocks,” April 25, 2019). Implementing such warnings in the front seats could therefore save up to 1,489 lives each year.