Impala and Avalon earn top ratings for side impacts

The Buick LaCrosse with standard side airbags is rated marginal, and so is the Chrysler 300 equipped with optional side airbags. The 300, Ford Five Hundred, and Ford Crown Victoria, all tested without their optional side airbags, are rated poor for side impact protection. (Note: The Ford Five Hundred with optional side airbags was tested last year and earned a good rating. With optional side airbags, the Five Hundred and its twin Mercury Montego earn the Institute's TOP SAFETY PICK 2006 (gold) award for good ratings in front, side, and rear tests.) According to Ford, the Five Hundred and Montego will be equipped with standard side airbags beginning with cars built in September 2006.

Side impacts are the second most common fatal crash type after frontal crashes. About 9,700 people were killed in side impacts in 2004. In crashes involving newer model cars in collisions with other passenger vehicles, more driver deaths now occur in cars struck in the side than in the front. This contrasts with the past when more deaths occurred in frontal crashes.

"The change reflects the big improvements manufacturers have made in frontal crashworthiness in response to Institute and federal government frontal crash test programs," says Institute president Adrian Lund. "These new crash test results show that the same improvements are beginning to be made for protection in serious side impacts."

Impala and Avalon are star performers: The side structures of these two cars performed reasonably well in resisting intrusion from the striking barrier during the crash test. Both cars are equipped with standard curtain-style side airbags designed to protect the heads of people in both front and rear seats.

In the test of the Impala, intrusion into the occupant compartment was minimized by the strong pillar between the front and back doors. The side airbags deployed from above the window frames and inflated between the heads of the crash test dummies and the intruding barrier.

"This is why side airbags with head protection are critical," Lund points out. "Without them, people's heads are vulnerable to being struck by the front ends of striking vehicles or trees and poles."

Side airbags are standard in more cars: Growing sales of SUVs and pickup trucks have exacerbated height mismatches among passenger vehicles, and these mismatches increase the risk of serious head injuries among occupants of side-struck vehicles. SUVs and pickups made up 31 percent of new vehicle sales in 1994, but the proportion has increased to nearly 47 percent.

Side airbags with head protection became standard in 2005 Avalons, 2006 Impala and LaCrosse models, and in the Lucerne when it was introduced to replace the LeSabre and Park Avenue models in 2006. The predecessor to the Azera, the Hyundai XG350, had standard combination head/chest side airbags for front-seat occupants. The replacement Azera was upgraded in 2006 with standard curtain-style airbags as well as chest airbags that protect both front- and rear-seat occupants.

Worst performers don't have side airbags: All three cars that earned the lowest rating of poor, Chrysler 300 plus Ford Five Hundred and Crown Victoria, were tested without their optional side airbags. In the Five Hundred, the driver dummy's head was hit by the intruding barrier. This produced high head injury measures. In a real-world crash of similar severity, the driver could have sustained a serious skull fracture and brain injuries. Rib fractures and internal organ injuries also would be possible.

The driver dummy's head was struck by the barrier in the 300 without side airbags, although this did not produce high head injury measures. Equipped with its optional side airbags, the 300 improved to marginal and head protection was good. However, injury measures from the dummy's pelvis and chest kept this car from earning a higher overall rating.

The Crown Victoria without side airbags is rated poor. It earned the worst structural rating in this group of large cars. Although the driver dummy's head was not struck by the intruding barrier, a high acceleration occurred when the head struck the window sill. High forces were recorded on the driver dummy's chest, indicating the likelihood of rib fractures and internal organ injuries. The Crown Victoria is available with optional combination head/torso side airbags for front-seat occupants. Ford is making design changes to improve this car's protection of occupants in side impacts and has asked the Institute to test a Crown Victoria with its optional side airbags. When the changes are made, the Institute will conduct the test and report the results.

How the side impact test is conducted: A vehicle's side evaluation is based on performance in a crash test in which the side of the vehicle is struck by a barrier moving at 31 mph. The barrier represents the front end of a pickup or SUV. Overall ratings reflect injury measures recorded on two instrumented SID-IIs dummies, assessment of head protection countermeasures, and the vehicle's structural performance during the test. Injury measures obtained from the two dummies, one in the driver seat and the other in the rear seat behind the driver, are used to determine the likelihood that a driver and/or passenger in a real-world crash would sustain serious injury to various body regions. The movements and contacts of the dummies' heads during the test also are evaluated. Structural performance is based on measurements indicating the amount of B-pillar intrusion into the occupant compartment.

(Source: IIHS)