Many cars globally feature fuel tank doors on the passenger side, a design choice rooted in safety, engineering, and industry tradition rather than a random decision.

• The primary reason is safety: being on the passenger side keeps drivers away from moving traffic when refueling, especially at the curb.
• Engineering logic also plays a role, as routing the fuel filler neck to the passenger side can be simpler and cheaper for manufacturers.
• This has become a common industry tradition, though some brands like BMW and Mercedes-Benz opt for the driver's side due to specific vehicle architectures or market preferences.