Fuel door position isn’t necessarily a random choice, but engineers would prefer the right side if they don’t face any practical problems. Although almost every feature and part in a modern-day automobile in meticulously designed and installed; but there are still some things which are rather flexible and don’t have to adhere to strict industrial standards and codes.
Nissan’s Steve Yaeger explained the logic,
“The placement of the fuel door is mainly a factor of fuel tank design, location and underbody packaging. With all of the structure and components located underneath the vehicle, (engineers) would quickly encounter restrictions in trying to route the filler tube to the same side on every vehicle.”
Mac Demere, from the All State Blog, dwells on such a feature: Why do some cars have gas caps on the left but others have them on the right side?
He writes that after performing an extensive research into the Federal Motor Vehicle Safety Standards; he found that there are no U.S. government regulations on the side of cap placement, which is the reason why we see such random diversity among the cars in this regard.
No legal or marketing motivation and very little practical implications show that the car company engineers are free to place the fuel doors according to the ease of packaging, as testified by Ford spokesman Mark Schirmer. He added,
“there’s not enough room — and no demand — for dual fuel doors.”
According to a Ford study, Americans in general, prefer left-mounted fuel doors as the cap on the driver’s side make it easier to place the car’s left fender close to the pump.
But countries where people drive on the left side of the road while sitting on the right side, such as Japan, India, the United Kingdom, Australia, Hong Kong, New Zealand, etc. prefer right-mounted fuel doors mainly due to the car manufacturing practices.