When a vehicle strikes a pedestrian, the outcome can range from minor bruises to fatal injuries, and the severity of these injuries is strongly influenced by two key factors: the speed at which the vehicle is traveling and the height of its front end. New research from the Insurance Institute for Highway Safety (IIHS) reveals a chilling truth: as vehicle speeds increase, so does the risk of severe harm, and this risk is magnified when taller vehicles, such as SUVs and pickups, are involved.
The study, based on data from 202 pedestrian crashes across several U.S. states, illustrates how the interplay between vehicle speed and height dramatically alters the likelihood of serious injuries. The findings suggest that U.S. pedestrians are at a greater risk of harm at lower speeds compared to their European counterparts, primarily due to the prevalence of taller vehicles on American roads. The research makes a compelling case for revisiting speed limits, particularly in areas dense with pedestrian traffic, and urges vehicle manufacturers to take action in designing safer vehicles.
Speed Matters: The Stark Increase in Injury Risk
The relationship between speed and injury risk is well-established: the faster a vehicle travels, the more likely it is to inflict severe harm on pedestrians. However, this latest study underscores just how much more dangerous this dynamic becomes when the vehicle involved has a taller front end, such as an SUV or pickup truck. Even a slight increase in speed can exponentially raise the chances of severe injury.
IIHS researchers found that a pedestrian struck at 20 mph had a 46% chance of sustaining at least a moderate injury, like a broken bone or concussion. That risk climbs significantly as speed increases. At 35 mph, the risk of moderate injury jumps to 86%, and the likelihood of serious injury increases to 67%. As for fatalities, the difference is stark: at 20 mph, the risk of death is just 1%, but by 35 mph, the chances skyrocket to 19%. At speeds exceeding 50 mph, more than 80% of pedestrians face the grim prospect of fatal injuries.
The Role of Vehicle Height in Amplifying the Danger
What makes this study even more alarming is the revelation that taller vehicles increase the risk of both moderate and serious pedestrian injuries, particularly when combined with higher speeds. For example, at a crash speed of 27 mph—the average speed of the 202 crashes analyzed—a median-height car would have a 60% chance of causing moderate injuries and a 30% chance of causing serious injuries. In contrast, a pickup truck, with its front end 13 inches higher than a typical car, was shown to have an 83% chance of causing moderate injuries and a 62% chance of causing serious harm.
These results reinforce previous IIHS studies, which found that vehicles with taller front ends are more likely to kill pedestrians when involved in crashes. The new study extends this understanding by showing that the impact of speed is even more severe in tall vehicles. For example, when the crash speed increases from 15 mph to 35 mph, the likelihood of serious injury rises from 9% to 52% for a median-height car, but for a median-height pickup, that risk shoots up from 11% to 91%.
U.S. Pedestrians Face Greater Risks Due to Vehicle Trends
The study also compares U.S. data with European crash data and finds that pedestrians in the U.S. are more likely to be injured at all speeds. This difference is largely due to the greater number of SUVs and pickups on American roads compared to Europe, where passenger cars still dominate. The shift towards taller vehicles in the U.S. has resulted in a higher risk for pedestrians, even at lower speeds.
IIHS Senior Statistician Sam Monfort, the lead author of the study, explained the significance of these findings. “Although SUVs are a growing share of the market in Europe, the passenger vehicle fleet there has long been dominated by cars. In contrast, the majority of passenger vehicles on U.S. roads today are SUVs or pickups,” he said. “These choices have very real consequences for pedestrian safety.”
Rethinking Speed Limits and Traffic Safety Measures
The findings have serious implications for speed limits, particularly in areas with heavy foot traffic. A commonly accepted benchmark for a “safe” crash speed is one where the risk of serious injury is 10% or less. According to the study, this threshold is reached at just 15 mph. This raises a troubling question: Is the typical 25 mph speed limit in residential areas too high for areas with high pedestrian activity, such as city centers or busy crosswalks?
Even modest reductions in speed can have a profound impact on pedestrian safety. For instance, reducing the speed limit from 30 mph to 25 mph would reduce the risk of serious injury by more than a third, from 50% to 32%. The study highlights the need for policymakers to carefully consider the growing number of taller vehicles when setting speed limits and designing urban environments with pedestrian safety in mind.
A Call to Action for Vehicle Manufacturers
The study also highlights the role of vehicle manufacturers in preventing pedestrian accidents and mitigating their consequences. While speed limits and urban planning are important factors, manufacturers can take proactive steps to reduce pedestrian risk. Modifying vehicle front-end designs to make them less hazardous to pedestrians, as well as equipping vehicles with advanced automatic emergency braking systems, could significantly improve safety.
“This study is a vivid illustration of how multiple factors—speed and vehicle height, in this case—converge to create negative outcomes on the road,” said IIHS President David Harkey. “Similarly, it will take a combination of actions from different corners of the transportation world to improve pedestrian safety.”
As the U.S. continues to see an increasing number of SUVs and pickups on the road, the implications of this study become even more urgent. While the focus has often been on the importance of reducing vehicle speeds to protect pedestrians, this research makes it clear that vehicle design also plays a critical role in ensuring safety. By addressing both of these factors, society can take significant steps toward reducing pedestrian injuries and fatalities in the years to come.