From a structural standpoint, this crash test doesn't look terrible. The front end looks to have absorbed the crash energy, leaving the occupant compartment largely intact. To an untrained eye watching this test as it happened (much like at 1:54 - 1:59 in the video) this probably didn't look like a candidate for "terrible". In the post crash damage shots, damage to the occupant compartment was minor, and only the upwardly tilted steering wheel gave any indication as to the dire nature of this crash test.
But then you see the numbers. Keep in mind that a HIC above 1,000 and/or a Chest G above 60 is likely to result in serious injury. Fatality is likely at HIC above 2,000.
Driver HIC was an astonishing 3,034, and at 4:33 into the video, in the close-up driver view, the cause of the high HIC was apparent. The seat belt is far too weak, and allows far too much forward movement. At the same time, the steering column moves upward several inches, and the driver's head is in a perfect position to slam into the thinly padded, unyielding hub of the steering wheel. The hub has an impaling effect, and the driver's head rebounds toward the seat with great force. It's clear that the impact has been very violent.
The HIC on its own is likely to prove fatal, but the Chest G measurement of 87 is also very poor. Again, the steering column does the damage. After the impact, it's bent on the bottom where the driver's chest slammed into the lower rim.
If this were ranked among the nearly 1,200 35 mph tests (comprising nearly 2,400 occupants, as each test includes a driver and passenger) that NHTSA has done, the driver's result for this truck would be among the worst. It would be 5th worst occupant on HIC, as well as 5th worst occupant on Chest G. Injury risk is hard to compare at these extreme levels of force, as the risk of severe injury is virtually 100%.
Worst HICs at 35 mph:
1. Driver, 1979 Peugeot 504: 4,611
2. Driver, 1982 Renault Fuego: 3,768
3. Driver, 1988 Chevy Van: 3,665
4. Driver, 1980 Honda Prelude: 3,063
5. Driver, 1979 Mazda Pickup at 30 MPH - 3,034
The average driver HIC in the 35 mph test for 1979 vehicles was only 1,223. At 30 mph (on 1978 vehicles), it was 942. When only cars are included (no trucks, SUVs, or vans), the 30 mph average drops to 843. Light trucks, vans, and SUVs were not tested at 35 mph until 1983, so all of the 35 mph tests were on cars.
But what if they had tested this vehicle at 35 mph instead of 30? Keep in mind that 35 mph has 36% more kinetic energy than 30 mph. The average HIC in the 1979 35 mph tests was 1,223, and the average car HIC in the 30 mph test was 843. The vehicles tested were not the same, so this data is only a rough guide, but the HICs on the 35 mph tests averaged 45.1% higher on cars. The discrepancy can vary widely from vehicle to vehicle. Chest G's averaged 45.9 at 30 mph and 55.4 at 35 mph, for a 20.7% rise.
So, if we take these averages and apply them to the Mazda pickup, we can expect a HIC of 4,402 and 105 Chest G's. This would make this truck arguably the worst performer in NHTSA history.
But I have reason to believe that actual results would be even worse. Looking closely, we can see that the cab and occupant compartment of the truck are beginning to deform. 36% more energy would probably translate directly into damage to the cab, causing more intrusion and "shoving" the steering column toward the driver with even more force. Combined with the increased speed of dummy movement, this would likely make the contact with the steering wheel much more violent. I believe that if this vehicle had been tested at 35 mph, the HIC would have likely exceeded 5,000 and may have been as high as 7,000. Chest G's would likely end up in the 115-135 range. There are a number of vehicles where the HIC has been twice as high at 35 as it was at 30, Usually these are poor performers that exhibit intrusion at 35.
The 1986 redesign of the Mazda pickup still had forces that exceeded the limits for likely serious injury, but a 35 mph crash test came back with a HIC of 1,434 and 65 Chest G's. These force levels are likely to be survivable.
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