ARLINGTON, Va. — In a recent series of frontal offset crash tests by the Insurance Institute for Highway Safety, all seven new or redesigned vehicles earned the top rating of good. The Institute tested three 2003 model midsize cars (Mazda 6, Infiniti G35, and Saab 9-3), two 2004 model minivans (Toyota Sienna and Nissan Quest), and two 2003 model large luxury cars (Lincoln Town Car and Mercedes E class). In addition to good overall ratings, five of the best-performing vehicles earned the Institute's "best pick" designation.
Vehicle ratings reflect performance in 40 mph frontal offset crash tests into a deformable barrier. Based on the results, the Institute evaluates the crashworthiness of passenger vehicles, assigning each vehicle a rating from good to poor overall. If a vehicle earns a good rating, it means that in a real-world crash of similar severity a belted driver would be likely to walk away without serious injuries.
"These results show the progress the auto manufacturers have made in designing safer vehicles," says Institute president Brian O'Neill. "Good performance in the Institute's frontal offset crash test program now is the norm. None of the vehicles we've tested in 2002 or in 2003 has received a marginal or poor frontal crash test rating. But it wasn't always that way."
Saab 9-3 is much improved compared with previous models
When the Institute tested the 1995 model Saab 900, predecessor model to the 9-3, "its structural performance was poor and there was major deformation of the passenger compartment," O'Neill says. "The 1999 model 9-3 was somewhat improved, but there were still structural problems. In contrast, the new 2003 9-3 is a good performer and a best pick. The structural design of this car is much improved compared with its predecessor models."
COMPARISON OF THREE SAAB MODELS: 1995, 1999, and 2003
Measured intrusion (cm) in 40 mph frontal offset tests
1995 SAAB 900
Poor performance: major intrusion
into the occupant compartment
1999 SAAB 9-3
Improved structural performance:
somewhat less intrusion
2003 SAAB 9-3
Good structural performance:
much less intrusion
Two other midsize cars also earn top rating
The Mazda 6 and Infiniti G35 have good structural designs. The safety cages of both vehicles held up well in the offset test, and most injury measures were low.
"There are now 11 inexpensive and moderately priced midsize car designs with good offset crash test ratings," O'Neill says. "There's no reason to buy a midsize car that doesn't do well in the Institute's test."
Two minivans earn good ratings
The Nissan Quest and Toyota Sienna are new designs for 2004. The Institute tested the Sienna twice, because in the first test there was a major fuel leak immediately following the crash. Toyota identified a defect in the manufacturing process of the plastic fuel tank and recalled the affected models. In a second test with one of the newly manufactured fuel tanks, there was no leak and the results for the instrumented dummy were similar.
"The driver space was maintained well in both tests of the Sienna, injury measures were low, and there was minimal intrusion into the occupant compartment," O'Neill says. The Sienna earned a good rating, and it's a best pick.
The Nissan Quest performed much better than its predecessor model, which the Institute rated poor in 1999. "There's still some room for improvement," O'Neill says. "The steering column moved up too much, and the dummy's head contacted the steering wheel through the frontal airbag. The new Quest is still a good performer but not a best pick."
Lincoln Town Car improves in second test
In the first test of this car, the structural performance was good, but during the crash the dummy's head rebounded against the door frame.
"The hit was hard and resulted in high forces on the head," O'Neill says. "We gave the Town Car an acceptable rating, but Ford officials thought they could fix the problem. They modified the way the airbag deploys, and in the second test the head injury measures were low. The Town Car with the modification earned a good overall rating."
Mercedes E class performs well
The structural performance was good, and there was minimal intrusion into the driver footwell area. During the crash, the dummy's head moved partway out the open window and contacted the door frame, so the dummy kinematics rating was only acceptable. But on all other measures the E class performed well, so it was rated good and a best pick.
Structural design is key
The Institute's frontal offset test into a deformable barrier is especially demanding of vehicle structure. The driver side hits the barrier, so a relatively small area of the vehicle's front-end structure must manage the crash energy. This means intrusion into the occupant compartment is more likely than in a full-width test.
"Good structural design is the key to good performance in the offset tests," O'Neill says. "If a car's front-end structure absorbs and manages the crash energy so the occupant compartment remains largely intact, with little or no intrusion into the driver's space, then the dummy's movement can be controlled, and injury measures are likely to be low. In contrast, poor structural design means greater likelihood of poor control of the dummy and high injury measures."
Institute and government tests complement each other
The Institute's crashworthiness evaluations are based on results of frontal offset crash tests at 40 mph. Each vehicle's overall evaluation is based on three aspects of performance — measurements of occupant compartment intrusion, injury measures from a Hybrid III dummy positioned in the driver seat, and analysis of slow-motion film to assess how well the restraint system controlled dummy movement during the test.
The federal government has been testing new passenger vehicles in 35 mph full-front crash tests since 1978. This New Car Assessment Program has been a major contributor to crashworthiness improvements — in particular, improved restraint systems in new passenger vehicles. The Institute's offset tests, conducted since 1995, involve 40 percent of a vehicle's front end hitting a deformable barrier at 40 mph. This test complements the federal test involving the full width of the front end hitting a rigid barrier. Both tests are contributing to improvements in crashworthiness — in particular, improved crumple zones and safety cages.
The same 40 mph offset crash test is used to evaluate new cars by the European Union in cooperation with motor clubs, by an Australian consortium of state governments and motor clubs, and by a government-affiliated organization in Japan.