Toyota Defies Safety Principles

The Toyota Van, and other similar era Japanese minivans, are designed in ways that ignore well-established crashworthiness principles, research and the very foundations of good occupant protection.  Additionally, these vans show an above average rollover propensity – especially noteworthy given their use and driver profile.  The following provides a historical analysis of the issue of occupant "packaging" and provides a background on the crashworthiness and stability of the Toyota Van.

Placement of seats in the front crush space of a vehicle defies all that has been known for a quarter century about protecting people from harm by effectively packaging human cargo.  It makes no sense.  Pioneers in the field recognized that car occupants were needlessly being killed and seriously injured in crashes because those who designed the cars failed to provide sufficient crash packaging for the occupants.

Hugh DeHaven, an innovator in the field of automobile and aircraft occupant crash protection, demonstrated early on that human bodies could withstand forces of severe car crashes without death or serious injury if they were properly "packaged" by their automobiles.  This provided a springboard for much of the later effort to increase the crashworthiness of motor vehicles.

In "Cushion That Impact!" (1950), DeHaven notes that the human body, if protected by a proper distribution of force, can tolerate more crash force than the car itself.  He showed that if the contact points were hard, injury resulted.  But if soft, light, yielding material was struck, the difference in result "was like the difference between being hit by a boxing glove or crowbar."

In "Crash Study Can Reduce Chances of Injury" (1952), DeHaven states "the principles used to provide greater safety...are closely related to principles used by packaging engineers for increasing the protection and safety of valuable goods in transit."  He goes on to say that the first tenet followed by packaging engineers is that "the package should not open up and spill its contents."  Col. John Stapp demonstrated these principles in his dramatic sled tests in 1950's.

Another safety trailblazer, Derwyn Severy, performed some of the first automobile collision experiments at UCLA, using both human and anthropometric dummy subjects.  These investigations facilitated procurement of critically needed data on human engineering aspects of collision injury minimization.

In "Technical Findings From Automobile Impact Studies" (1956), Severy says:

...virtually all types of vehicular collisions could occur without motorist injuries if it were practical to build onto the car a sufficient amount of structure of suitable strength to keep within safe limits the decelerations (and the accelerations) encountered during collision.  An opposite extreme of the protection affords the motorists by such a hypothetical car structure is typified by the motorcycle.  For most collisions it provides negligible protection because the motorist in this case is outside the structure inside of the converse.   (emphasis added)

In "Active Versus Passive Motorist Restraints" (1970), Severy notes that the advantage of the seat belt, in addition to moderating the force with which the motorist impacts interior structures during a collision, is that it keeps the occupant "within the more protective confines of the passenger compartment."

William Haddon, Jr., M.D. first defined the scientific concepts dealing with the prevention and amelioration of motor vehicle crash injuries.  We now use the term "crashworthiness" to describe the principle Haddon articulated.  He was the first head of the National Highway Traffic Safety Administration, and with the assistance of Bob Brenner, personally wrote to the first motor vehicle safety standards.  He continued his work at the Insurance Institute for Highway Safety.

In "Reducing Truck and Bus Losses – Neglected Countermeasures" (1971), Haddon points out that the "properly packaged" human body is capable of high force tolerance without injury.  Haddon goes on to say that "the failure to prevent most, if not virtually all injuries of any severity...must be attributed to inadequacies..in design."

In "A Logical Framework for Categorizing Highway Safety Phenomena and Activity" (1972), Haddon gives the following analogy:

...we "package" articles shipped by mail so that over the full range of anticipated impact severities the forces of impact will be so spread out in time, space, and magnitude that they will not exceed the damage thresholds of the package's contents.

This principle in nicely illustrated in a film that IIHS did in the early 1970's.

NHTSA crash tested the 1984 and the 1990 Toyota Van.  There was little change to the vehicle; however, the injury criteria did differ a fair amount.  In the 1984 test, the head injury criteria (HIC) for the driver indicated that serious or fatal injuries were likely.  In the 1990 test, the HIC was lower but the injury criteria for chest and femur loads have increased. 

In NHTSA's technical assessment paper "Relationship Between Rollover and Vehicle Factors" the Toyota Van was tested in a tilt-table, the results of which NHTSA says correlate to rollover accidents.  The figure for the Toyota Van is worse than that of the Suzuki Samurai, a vehicle which Consumer Reports (July 1988) suggested should be removed from the road because of it's stability problems.

(11/22/02)