Although automatic emergency brake systems have proven to prevent typical front-to-rear crashes — reducing rates of rear-end crashes by 50% and rear-end crashes involving injuries by 56% — a new study from the Insurance Institute for Highway Safety is exploring additional opportunities to increase the effectiveness of the technology.

The findings indicate that extending the functionality of automatic braking to address less common types of rear-end crashes such as those involving turning, changing lanes or striking heavy trucks or motorcycles would help maximize the benefits of the technology.

In fact, IIHS estimates that automatic braking could potentially prevent as many as 70% of front-to-rear crashes involving passenger vehicles as striking vehicles and 20% of all passenger vehicle crashes reported to police.

To determine what types of rear-end crashes in which vehicles with automatic braking are involved, IIHS examined police crash reporting data from 23 states during 2009 to 2016 for striking passenger vehicles with and without autobrake among models on which the system was optional. 

Many of the crashes during the study period involved typical scenarios that current autobrake systems already address.

For example, over two-thirds of the crashes happened when the road surface was dry, the striking vehicle was moving straight, or the vehicle hit was slowing or stopped. More than 50% of crashes occurred at speed limits of 45 mph or below, and about half of the vehicles struck were cars.

The remainder of the crashes studied involved less-typical situations.

For example, vehicles with the systems that are involved in crashes were more likely to be turning or to strike a vehicle that was turning or changing lanes. In some cases, the vehicle struck a non-passenger vehicle or special-use vehicle such as a medium- or heavy-duty truck or motorcycle. Other atypical situations involving vehicles with automatic braking included crashes on a snowy or icy road, or on a road with a speed limit of 70 mph or higher.

The findings indicate that designers of autobrake to date have focused on creating technology that addresses the most common types of collisions.

Going forward, IIHS believes there's a clear need for automatic braking systems that reliably detect other vehicles.

For example, a 2017 IIHS research report suggests that automatic braking could prevent up to 13% of passenger vehicle crashes with motorcycles. Systems that reliably detect large trucks could prevent underride crashes.