IIHS research reveals large vehicle blind zones increase left-turn pedestrian crash risk by 70%, with thick A-pillars, bulky mirrors, and tall hoods identified as primary visibility obstructions.

Vehicles with large driver-side blind zones are 70% more likely to strike pedestrians during left turns compared to vehicles with small blind zones, according to new research from the Insurance Institute for Highway Safety. The study identifies thick A-pillars, bulky side mirrors, and tall hoods as primary design elements that obstruct driver visibility and contribute to turning crashes.

Pedestrian deaths have increased 78% since reaching their lowest point in 2009, now accounting for more than 7,300 crash fatalities annually. Higher vehicle speeds and vehicle-centric infrastructure designs are among the suspected factors driving this increase. The shift toward vehicles with taller, blunter front ends, particularly SUVs and pickups, represents another contributing factor, as these vehicle types demonstrate higher rates of pedestrian injury and fatality in crashes.

“These results clearly identify problematic aspects of vehicle design,” said IIHS President David Harkey. “The challenge for automakers will be to find ways to address them that don’t diminish the protection vehicles provide to their occupants in a crash.”

IIHS researchers employed a camera-based measurement technique to assess blind zones in 168 vehicles from two driver vantage points: a 5-foot-9 man and a 4-foot-11 woman. These heights correspond to commonly used crash test dummy sizes and represent a broad range of the driving population. Because vehicle designs remain consistent across multiple model years, the measurements applied to numerous make, model, and model year combinations, enabling analysis of a large volume of pedestrian crashes.

The research team defined blind zones blocking more than 30% of the driver-side view as large, those blocking 20-30% as medium, and under 20% as small.

For a 5-foot-9 driver, passenger cars exhibited the largest average driver-side blind zones, while pickups had the smallest. However, pickups and SUVs generally provided narrower windshield fields of view. The nearest visible point on the ground ahead of these vehicles was also positioned farther away from the driver.

For a 4-foot-11 driver, SUVs and pickups demonstrated the largest average driver-side blind zones. These vehicle types also provided the narrowest field of view and greatest distance to the nearest visible ground point.

The study identified three key measurements affecting left-turn pedestrian crash risk:

Driver-side blind zone size: Average blind zones blocked 27% of the area to the left and front of vehicles for 5-foot-9 drivers. For 4-foot-11 drivers, average blind zones blocked 33% of this critical scanning area.

Windshield field of view: The average windshield provided an 88-degree field of view for drivers of either height. A front field of view of 85 degrees or less was associated with a 51% increase in left-turn crash risk versus field of view wider than 90 degrees.

Nearest visible point: The nearest visible ground point averaged 26 feet ahead for taller drivers and 30 feet for shorter drivers. A nearest ground-level visible point more than 30 feet from the driver was associated with a 37% increase in left-turn crash risk.

Analysis of nearly 4,500 police-reported pedestrian crashes in seven states revealed that large driver-side blind zones were associated with a 70% increase in left-turn pedestrian crash risk compared to small blind zones. Medium driver-side blind zones were associated with a 59% increase in left-turn crash risk.

Researchers calculated these estimates by comparing the ratio of left-turn crashes to straight-moving crashes for each blind zone category. Straight-moving crashes were included to account for how frequently vehicles encounter and strike pedestrians independent of driver-side blind zone effects.

A separate analysis of 3,500 crashes showed passenger-side blind zones had no significant impact on right-turn crash risk.

“When a driver’s view is partially blocked, it’s easy for a person in the crosswalk to disappear from sight,” said Wen Hu, senior research transportation engineer at IIHS and lead author of the study. “That’s exactly the kind of situation that leads to turning crashes.”

Some vehicle characteristics that increase blind zone size also enhance occupant safety in other crash scenarios, creating complex design tradeoffs. Thick A-pillars contribute to roof strength, protecting occupants during rollover crashes, while long hoods relate to larger crumple zones needed to manage frontal impact forces.

Several technological interventions could address visibility challenges without affecting vehicle structure:

Road and crosswalk design changes could also mitigate risk. Traffic signals can provide pedestrians several seconds to begin crossing before the light turns green for vehicles, allowing drivers to identify crosswalk occupants before initiating turns. Extended curbs at intersections place waiting pedestrians in the driver’s line of sight and reduce pedestrian crosswalk exposure time.

“The driver’s ability to see is a fundamental element of safety that hasn’t received enough attention,” Harkey said. “That should change with our new ability to easily measure vehicle blind zones and assess their effects on crash risk.”