Manufacturers design vehicles to pass safety tests, not necessarily to pass tests of real life collisions. This distinction could cost you your life.
In the real world the cost of a $0.12 part can make a massive difference in profit when a manufacturer builds a million vehicles. That point is rarely understood when members of the public scratch their heads over the unethical practices of manufacturers who use cheap parts or production processes that result in deaths.
This similar problem also rests with instances where manufacturers must meet various standards and tests in order to certify their vehicles as safe for the road. Manufacturers build to pass government safety tests, not to pass the tests of real life collisions. Manufacturers know what tests they will need to pass, at what speed, angle of impact and overlap with a barrier, and they create designs specifically to pass those very specific tests. But collisions in the real world do not occur in the manner of those tests. In fact the conditions in real life that match government safety tests are very, very rare. This comment is not made without personal experience.
While an accident investigator working under contract to Transport Canada Zygmunt Gorski was one of many investigators in the late 1980s who was given the assignment of finding real-life collisions to match the standard, frontal, 50 km/h, barrier impact test that was being used by Canada and the U.S. in their safety compliance programs. The difficulty in finding such a real-life collision was known even before the program was commenced because hundreds of previous collisions had already been documented under other Transport Canada research studies. In the end not a single collision was found which matched those required parameters. Some latitude had to be used to bring the study to about a dozen or two crashes which were similar but still not exactly comparable.
When manufacturers design vehicles for the purpose of passing these very specific test conditions the performance of a vehicle can suffer when the real life conditions do not match the standard. This is what can happen, for example, when we observe vehicles that disintegrate during side impacts. The side impact tests that are performed are with passenger cars as the “bullet” vehicles, striking the sides of other passenger vehicles. In other instances specific sleds are designed to mimic the specifications of such a bullet passenger car. In all these instances the struck vehicle sustains contact at a specific location that is previously known by the manufacturer. Thus the manufacturer designs the vehicle to match that specific test. In no instances, for example, does the standard test take into account that the direct contact may occur to other portions of the side of the target vehicle. Also such tests do not take into account the rotation of the vehicles and what addition or altered forces make take place during that rotation. Similar problems exist with side impact tests with narrow objects such as poles.
Thus when a real life collision occurs involving a side impact the immediate response of investigators is to comment on how severe the collision must have been in order to produce separations in the vehicle structures. As police investigations are the only ones that hit the headlines of news media there is minimal recognition that structural problems or failures of vehicles could be an issue because of the biased focus of police investigations toward laying charges against drivers. The training that police receive with respect to collision reconstruction is vastly focused on vehicle speed and other driver failures. The closest that police training comes to assessing vehicle structural issues is when they have been involved in the rare activity of measuring vehicle crush for the purpose of determining the extent of energy dissipation which then leads them to determine the collision severity and ultimately the speed of the vehicles. But in those rare instances the purpose of such actions is not to look at the evidence to evaluate where some structural component has failed prematurely.
This detailed evaluation of the physical evidence is greatly curtailed now-a-days with the advent of event data recorders. Now-a-days the collision reconstructionist need not be greatly familiar with the physical evidence on the roadway or on the vehicle. The belief becomes more pronounced that all is needed is a good understanding of how to extract data from a “Black Box” and it is this module that will contain all the evidence that matters. Theoretical discussions amongst police reconstructionists contain the caveats that police need to make sure that the extracted data matches the physical evidence. But if the investigator is not familiar with the physical evidence then that warning is of little effect. Again most of the evidence that police investigators consider is the evidence related to vehicle speed, not to other important issues such as vehicle crashworthiness.
The problem is that many factors that relate to the public’s safety on the road are not clearly identified. The failure of vehicle structures in crashes is one of those factors. We will provide a safer roadway environment when we return to the original roots of scientific collision reconstruction where it was stated that HVE (Human, Vehicle and Environment) factors must all be considered and evaluated, and to focus on just the Human produces a biased analysis.