To determine the location of the fuel tank, follow these basic guidelines:
- keep the fuel tank away from the engine (if the engine is in front, the reservoir should be placed on the back, and conversely); placing the fuel tank at the rear of the car is preferable, because the most severe road accidents are the result of frontal collisions, however, the invasions usually take place. at medium speeds;
— in some cases, constructors, wanting to create more comfortable conditions and protect the cabin against fuel from entering it, they put the fuel tank, on the outside of the bodywork; however, with such a solution there is a greater probability of the tank's exposure to damage not only in a road accident, but also due to the impact of uneven road surfaces.
Research results indicate, that fuel may also leak from a fuel filler opening that is not tightly closed with a plug. During the tests of car collisions at different speeds, a detailed analysis of this phenomenon was carried out. The results were as follows: if the tank deformation is minor, it is the cork that rises a few millimeters, which causes an annular gap, fuel may spill through it; if the fuel tank deforms significantly, the tap comes off, and the filler hole is damaged. When concentrated dynamic force acts directly on the tank, it is significantly damaged, and a jet of fuel gushes from the filler opening to a height of approximately 4 meters.

The described phenomena testify to this, that in the event of similar damage, a combustible mixture may form. When the cap tightly covers the filler hole, the fuel cannot run out. Stated, that damage to the fuel tank can only be caused by considerable forces. The results of special tests of the fuel tank itself showed, that it can undergo significant deformation without cracking (accompanied by leakage of fuel), even when it is filled with fluid.

Based on the results of car resistance tests against hitting a metal obstacle (the fuel tank was located in the front of the car), carried out at different speeds, the following conclusions were made:
— low-velocity impacts do not break the tank walls, and the tank remains in place;
— medium-velocity impacts cause slight deformation of the tank walls without cracking; fuel tank, it works as an element that transfers forces to the body and deforms the body; in case of further increase, collision speed, the deformation of the fuel tank increases, there are slight cracks in these places, in which the tank is in contact with protruding parts (body mounting bolts, body or frame parts, etc.), in this case the fuel is already spilling;
— as a result of the impact at very high speed, the fuel tank is completely destroyed, and fuel quickly spills a few meters around the car.

The research have shown, that the fuel tank has sufficient mechanical resistance to the action of dynamic forces, but when the collision occurs at high speed, this is when fuel flows out of the filler opening, and in exceptional cases also from cracks in the tank.