Safe fuel tank design involves storing highly flammable fuel, which means being leak and emission proof. It must include a gauge and be refillable. It must connect with or incorporate a filter and a pump. How it is fabricated and where it is located—all involve safety considerations. The safest location has proven to be out of the ‘crumple’ zone, which means, where the engine is in the front of the vehicle, and in front of the rear axle.
Not locating the fuel tank where it is as protected as possible by the vehicle frame and where it is within the crumple zone has increasingly been regarded as an unsafe design because it increases the risk of a collision causing a fire following tank or fuel line rupture.
The discussion of this issue dates back at least to the 1970s, linked notoriously with the Ford Pinto, an early sub-compact, the subject of lawsuits, an investigation by the National Highway Traffic Safety Administration (NHTSA) over the placement of its fuel tank between the rear axle and the rear bumper.
Chrysler acquired the profitable Jeep brand in 1987 and the acquisition brought with it an inherited Jeep design placing the fuel tank behind the rear axle. In 2005, Chrysler moved the gas tank for the Grand Cherokee model in front of the rear axle to make more cargo room, it said, but otherwise continued using the inherited design in other models. Jeeps with the inherited design have been reportedly involved in what should otherwise have been non-fatal collisions but allegedly caught fire when their gas tanks were punctured on impact.
In 2010, a petition from a consumer safety lobbying group prompted an NHTSA investigation which, in 2012, reportedly concluded that the pre-2005 Jeep Grand Cherokee was associated with a higher number of rear-end collision gas tank vehicle fires than non-Jeeps and that it would investigate other Jeep models. In June 2013, the NHTSA ordered Chrysler to recall certain models for presenting an “unreasonable risk” of “burn[ing] to death in rear impact crashes.” Chrysler complied with the recall.
The ‘fix’ agreed upon was to add a tow hitch on the 1.5 million affected vehicles. Some safety experts and victims’ lawyers say it is inadequate, quoting the deposition of Chrysler engineer François Castaing, the so-called father of the Jeep, two years before the recall: “A tow package does not protect the tank.” (The context of the statement may be important, and is missing here.)
Some safety experts and the NHTSA have alleged that Chrysler’s recall has been slow. Chrysler maintains that there is no defect, the vehicles are safe, met all the safety standards at the time of sale and that the fire deaths resulted from high speed crashes “far in excess of any reasonable expectations” for fuel tank performance.
This story is in the news (again) now as details of the above-noted meeting are coming out in depositions related to ongoing lawsuits, and as the mid-March 2015 recall target date has just passed.
There may be “better” and “best” locations for fuel tanks, but no location of a fuel tank will guarantee complete protection against fuel leakage in a severe crash. Fortunately, vehicle fires and explosions caused by traffic accidents are and always have been very rare occurrences.
If fiery death was a risk worth worrying about for the average motorist, then the answer would be to operate diesel vehicles. Spilled gasoline will readily burn, and when vaporized will explode, but diesel fuel is much less volatile.