It happens in the blink of an eye. You’re driving and take your eyes off of the road to reach for your coffee cup or turn around to tell your kids to quiet down, and when you look ahead, a pedestrian is crossing the road right in front of you. You hit the brakes—but it may be too late.   

Unfortunately, this scenario is all too common. One out of three vehicle-pedestrian crashes involves a vehicle going straight as a pedestrian crosses the road. And fatalities involving vulnerable road users, such as pedestrians, bicyclists, and motorcyclists, have increased over the past decade.

To prevent these crashes, automakers now offer a “pedestrian detection” system in some models. If the system detects that a pedestrian could be in the vehicle’s travel path, it alerts the driver or employs automatic emergency braking, preventing what could be a fatal crash. 

The Volpe team found that pedestrian crash avoidance/mitigation systems can potentially reduce up to 5,000 vehicle-pedestrian crashes and 810 fatal vehicle-pedestrian crashes per year. (Hawlan/123RF photo)

As pedestrian detection technology becomes integrated into the cars we drive, we must ask: How effective are these systems in preventing pedestrian crashes and injuries? How do we measure safety? A team of advanced vehicle experts at U.S. DOT’s Volpe Center conducted a study to find out.

Measuring Safety Benefits

Volpe researchers analyzed the potential safety benefits of pedestrian detection systems, also known as pedestrian crash avoidance/mitigation (PCAM) systems, in terms of crash avoidance and crash mitigation measures. The research was sponsored by the National Highway Traffic Safety Administration (NHTSA).

“When a car manufacturer does this, they focus on the safety of their own vehicle fleet,” said Mikio Yanagisawa, an advanced vehicle technology expert at Volpe. “We took real-world pedestrian crash data and track test data from multiple manufacturers’ PCAM systems and quantified a national safety benefit.”

The researchers used a quantitative measure to determine the effectiveness of PCAM systems. They devised a method using test data, real-world driver behavior data, and historical crash data to assess safety impact.

“We projected how many crashes these systems could avoid and how many lives they can save,” said Yanagisawa.

This information helps NHSTA inform consumers about advanced safety features and also helps determine what safety benefits consumers need to know about.

Technology Evolves

The Volpe team found that PCAM systems can potentially reduce up to 5,000 vehicle-pedestrian crashes and 810 fatal vehicle-pedestrian crashes per year. These crashes account for 8 percent of crashes where cars strike a pedestrian and 24 percent of same crash types where fatalities were involved.

If a crash is unavoidable, PCAM systems could reduce the resulting number of injured pedestrians through impact speed reduction.

Yanagisawa added that the steps his team took to carry out this research highlight the team’s technical capabilities—whether it’s collecting or analyzing crash data or naturalistic driving data, or conducting system performance testing, crash simulations, or human-factor-based experiments. These capabilities can be applied to other areas of safety research involving advanced vehicle technology.

Read the full report: Estimation of Potential Safety Benefits for Pedestrian Crash Avoidance/Mitigation Systems.