Rear-End Crash Neck Injury Test Fails To Give Most Vehicles ‘Good’ Rating in New Evaluation: IIHS

New rear-end crash tests have been introduced after vehicles with “good” ratings continued to cause whiplash injuries.

A new rear-impact safety evaluation found that only four of the first 18 small SUVs tested earned a “good” rating for whiplash protection.

The Insurance Institute for Highway Safety (IIHS) announced the whiplash prevention test on January 27, noting that neck sprains and strains, which typically result from rear impacts, are the most frequently reported injuries in U.S. auto insurance claims.

Seat and head restraint evaluations simulate rear-end crashes using test dummies to assess how well vehicle designs limit the risk of neck injuries.

Earlier head restraint tests used a single crash pulse meant to replicate a 20-mph rear-end impact. Those evaluations were phased out in 2022 after automakers improved seat and head restraint designs, leading nearly all tested vehicles to receive good ratings. 

Despite those gains, whiplash injuries continued to occur in real-world crashes, even among occupants of vehicles with strong prior scores, prompting the need for a more demanding test to drive further safety improvements.

New Rear-End Crash Neck Injury Test

To better understand how vehicle design affects injury risk, IIHS tested 36 late-model vehicle seats at three different rear-impact speeds. Researchers measured the forces and motion experienced by a test dummy, then compared those results with real-world injury claim rates from the IIHS-affiliated Highway Loss Data Institute.

Like the previous 20 mph test, the new evaluation measures how quickly the head restraint moves into position behind the dummy’s head and the acceleration experienced by the upper spine.

The updated test also adds a 30-mph rear-impact simulation and measures pelvic movement to evaluate how well the seat absorbs crash energy. It also examines how the head tilts and bends relative to the neck during impact.

“This new test challenges automakers to further improve their seats and head restraints to provide better protection in the rear impacts that typically cause these injuries.”

— David Harkey, President, IIHS

Ideally, the dummy should sink into the seatback so the pelvis stays aligned with the head, while the head restraint supports the head in a natural upright position. If the restraint makes contact above or below the head’s center of gravity, it can force the chin sharply upward or downward.

For the new evaluation, the measures were combined to gauge three aspects of injury prevention, including head and spine support, the interaction of the head with the head restraint, and how well the seat manages the energy transferred to the occupant’s body.

Neck Injury Test Results 

Vehicles earning good ratings provided strong protection across nearly all measures at both impact speeds. Models rated poor fell short in all three injury prevention areas and performed particularly badly in at least one.

Good:

• Audi Q3
• Hyundai Ioniq 5
• Subaru Forester
• Toyota RAV4

Acceptable:

• Buick Encore GX
• Chevrolet Equinox
• Honda CR-V
• Jeep Compass
• Kia Sportage
• Mercedes-Benz GLB-Class
• Mitsubishi Outlander
• Volkswagen Taos
• Volvo XC40

Marginal:

• BMW X1
• Nissan Rogue

Poor:

• Ford Bronco Sport
• Hyundai Tucson
• Mazda CX-50

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