The Subaru Outback returns for the 2017 model year with a feature that could help fleets reduce the risk of low speed collisions that occur while the driver is backing up the vehicle.

The Outback, and several other 2017 Subaru vehicles, can now be equipped with Reverse Automatic Braking, an enhancement to the EyeSight safety and driver-assisting system. We're familiar with forward automatic braking systems — also known as collision avoidance systems — that can brake or steer the vehicle to avoid or lessen the impact of an imminent collision.

These systems use forward-facing sensors and calibrate speed and proximity to vehicles on the roadway ahead. This technology is widely credited to a team of engineers at Hughes Research Laboratories in Malibu, Calif., who first demonstrated a radar-based system in 1995. Early adopters of forward warning systems included the Lexus SC400 and Cadillac STS. Automakers have agreed to make forward automatic braking a standard feature by 2022.

OK, back to Subaru. Their new rear automatic braking system functions similarly to the forward systems, but at lower speeds. After testing it, I can attest that it would help combat distracted backing and add an extra layer of protection of smaller objects behind the vehicle such as children or lower walls and poles.

Here's how the system works. Rather than being radar based, the system is sonar based. It uses four small sensors mounted to the rear bumper that appear as 2-inch dots to the naked eye.

You can tell the system is engaged, when you see "RAB On" displayed in the lower left corner of the dashboard display when you put the vehicle into reverse. This is coupled with the warning, "Check Surroundings Before Backing Up."

The sonar sensors begin detecting objects in a 5-foot field behind the vehicle and 6 inches outside the width of the rear end. The system operates when the vehicle is traveling up to 9 mph.

It provides progressive audible alerts at first, and then reduces engine power when a collision is imminent. If the driver fails to apply brakes, the system will panic-stop the vehicle, and informs the driver to apply brakes to keep the vehicle from rolling away. If the driver doesn't apply the brake, the vehicle will activate the electric parking brake.

The system will be cancelled if the driver presses the brake pedal or accelerator.