With most cars unless there’s an over-riding need to put it on the left, will put it on the right side. They fit the filler cap and tank that side because, when full, it’s heavy 40Kgs or so for 60Ltrs of fuel. The only other asymmetric bits of the car are the steering column and driver so it helps it balance the car. Remembering of course that most cars would have been designed from the outset to be LHD.
Japanese cars and older Brit cars being the exception because they would have been designed from the outset to be RHD.
How true that is I’m not sure, but looking out in the Car Park there is a Seat, a VW, A Volvo and a Renault all caps on the right, and a Toyota, cap on the left.
Our Shitroen C3 Picasso (French) has it on the left….
You’ve got to wonder why, in this day and age of computer design and international car models, the manufacturers don’t do the sensible thing and put two filler caps on each car, one either side.
Extra cost to the manufacturer for something that doesn’t really matter, given that you can drive up to a petrol pump on either sides, and even if you can’t the hose will reach on many cars.