The Insurance Institute for Highway Safety has evaluated the crashworthiness of the Sonata in two 40 mph frontal offset crash tests into deformable barriers.

During the first test, the driver seatback failed to maintain its adjustment in its locked precrash position, resulting in forward rotation of the seat back into the inflated airbag. The seat back then moved rearward and after the crash was found in a semi-reclined position. Postcrash inspection showed the lap portion of the driver lap/shoulder belt was partially caught beneath the seatback adjustment lever and had likely activated the lever during the crash.

Starting on August 1, 2005, Hyundai put into production a new seatback adjustment lever designed to minimize interaction with the seatbelt and ensure the belt cannot slide between the lever and the plastic trim on the side of the seat. Hyundai has recalled all 2006 Sonatas manufactured before August 1 to replace the levers at its cost.

A second test was conducted to assess the effect of the fix. Hyundai sent the Institute a replacement seatback adjustment lever that was retrofitted in a Sonata produced before August 1, 2005. In the second test, the seat back remained in place.

The evaluation of the Hyundai Sonata is based on the second test, except for the structural rating, which is based on both tests.
 

In the second test, measures taken from the head, chest, and legs indicate low risk of injuries to these body regions in a crash of this severity. Forces on the neck when the head hit the roof rail indicate that neck injuries would be possible. Head acceleration from the roof rail hit was low.
 

Dummy movement was well controlled in the second test. During rebound, the dummy’s head hit the roof rail.
 

Measures taken from the dummy indicate that a fracture of the pelvis would be likely in a crash of this severity. Rib fractures and/or internal organ injuries would also be possible.
 

Measures taken from the dummy indicate a low risk of any significant injuries in a crash of this severity.
 

Driver: The dummy's head was protected from being hit by any hard structures, including the intruding barrier, by a side curtain airbag that deployed from the roof.

Rear passenger: The dummy's head was protected from being hit by any hard structures, including the intruding barrier, by a side curtain airbag that deployed from the roof.