American cars and trucks continue to grow in size, and new research indicates that the added height comes at the cost of safety.

According to a recent study published by the Insurance Institute for Highway Safety (IIHS), vehicles with taller and blunter front ends are 45% more likely to cause fatal accidents involving pedestrians than smaller passenger and commercial vehicles.

"We expected these vehicles to indeed pose a higher risk of pedestrian death," said David Harkey, president of IIHS in an interview. "But I'm not sure we expected the number to be this high."Pedestrian fatalities in the U.S. have reached a 40-year high. NATIONAL Pedestrian fatalities in the U.S. have reached a 40-year high. The number of pedestrian deaths in the U.S. has steadily increased, reaching the highest level in over 40 years. Pedestrian fatalities are rising faster than overall road deaths, surging over 80% since 2009.

This new study adds to the growing body of evidence that larger vehicles are a significant factor in pedestrian fatalities. However, transportation safety experts note that there are multiple reasons for this increase, including road design and vehicles traveling at higher speeds.

Researchers from IIHS examined data from nearly 18,000 pedestrian-involved crashes. They found that pickups, SUVs, and vans with a hood height of over 40 inches are 45% more likely to cause fatal incidents than shorter vehicles with a hood height of 30 inches or less.

The study also revealed that the shape of the vehicle's front end matters. Among mid-sized vehicles with a hood height between 30 and 40 inches, vehicles with a blunt front-end profile are 26% more likely to be involved in pedestrian fatalities than vehicles with a sloped front end.

Harkey emphasizes that the height and profile of the front end of these vehicles may contribute to more severe injuries.

Roads are becoming increasingly hazardous for pedestrians; Minority fatality rates worse BUSINESS Roads are becoming increasingly hazardous for pedestrians; Minority fatality rates worse "A vehicle hitting a pedestrian much higher in the torso area tends to push the pedestrian forward and downward," he said. "As a result, you have much more severe injuries, often with more head injuries."

Safety experts also point out that the added height of these vehicles can worsen visibility.

"The front end of some of the best-selling vehicles in America (full-size pickups) has a height of up to 55 inches, creating huge blind spots ahead that are particularly dangerous for children and wheelchair users," said Angie Schmitt, author of "Right of Way: Race, Class, and the Silent Epidemic of Pedestrian Deaths in America.""Poor and vulnerable people are paying a high price for this arms race among car consumers," Schmitt said in an email.

According to IIHS, over the last three decades, the average passenger car in the U.S. has increased by approximately 4 inches in width, 10 inches in length, 8 inches in height, and 1,000 pounds in weight. The non-profit organization is funded by auto insurance companies and associations and aims to find ways to reduce the number of crashes and associated losses.

"We need automakers to pay attention to these kinds of findings and start thinking about what they can do in terms of designing their vehicles to protect vulnerable road users in our system," said Harkey. "We really need to think comprehensively about what we need to do to protect everyone on our roads—not just those inside the vehicle but also those outside of it."