Tends to be the newer ones.

Tends to be the older ones.

No, the worst of all.  
Too low, splashes out when topping up,
hard on the back bending down to fill
and hit in rear end collisions.
I'd never buy a car with such a stupid fill location.

??? Perhaps it depends if the designer is left or right handed.
It is best to be on the opposite side from the exhaust, but dual
exhausts defeat that safe design approach.

The passengers side makes sense when in RSD countries you pull up to the
side of the road to fill up.
Makes sense when you run out and fill from a can.

I don't mind that my older car fills from the passenger side, because
that side of the pumps isn't as busy anymore.  <:)
Our problem is that my wife's newer car fills from the other side and I
get it confused when pulling into a gas station.

Most of the passenger side fill cars are European.   It seems that in
some countries fuel pumps are sometimes right at the curb and a driver
pulls off to the side of the road to fill up, in which case the fuel
filler needs to be on the passenger side of the vehicle.  Think of it
like parallel parking next to a fuel pump.  This method is just about
never seen in the US.  For US self-serve use it is slightly more
convenient to have the filler close to the driver.  Best of all is to
live in New Jersey and not have to pump your own!

Rear fill is very bad for fuel spillage and because it puts the fuel
tank in harm's way in a rear end collision. This is the way nearly all
US made cars used to be, but it has gone away due to better safety
engineering.

John

I remember reading something somewhere that said the majority of cars
smashed were hit on the passenger  side quarter panel. It was determined
to be safer to have the gas filler neck on the left than the right.
When it was behind the license plate in the back the filler neck tended
to get damaged from being rear ended - even light bumper taps could
spring the filler neck to crack the seam where it joins the tank.

I thought it was rather unique that GM hid the filler door on some 50's
models. Caddy behind the LR Tailight and the 57 Bel Air's in the end of
the quarter panel behind the chrome trim.

The 68- 70 Dodge Chargers had an odd location of the " top " edge  of
the LR 1/4 panel.

And look at the 60's & 70's Corvettes having the filler on top of the
rear - I'll call it the trunklid even thought there was no opening for a
trunk.

When I worked at Amaco in 1984 a dude come in with new Porsche - might
of been a 911? it wasn't the Carera, it had those flip up headlight
modules.,,, anyway there is a rubber flap that you could fold out after
the filler door is opened so it could protect the quarter panel from
knick knicks from the gas nozzle. Well after the guy pulled the gas cap
off the car he didn't realize he was at full serve. I'm ready to run the
nozzle in the opening and the rubber boot around the gas nozzle bumps
his quarter panel before he got the rubber flap unfolded. This guy
almost had a heart attack. I reassured him there was no dent or scratch.
I had to pull the nozzle out so he could check, then he pulled out the
rubber protector flap and told me to be more careful. We never saw that
car or that dude again.

Best one was when Daddy - O was trailering a 20' Renell cabin cruiser in
the early 80's. Pulling in the gas staion to fill the boat up - the
filler hole is 4 feet above your head. One person had to get in the back
of the boat and the hose had to be given to the guy up above. The guy on
the ground operated the pump. hahahaaha.

My cars filler neck locations were:

73 Impala, Behind Lic Plate
68 LeSabre, Behind Lic Plate
78 Olds 88, Behind Lic Plate
91 Bonneville, LR 1/4 panel
89 Z - 24, RR 1/4 panel
05 Park Ave, LR 1/4  

     Harryface    
05 Park Avenue, 33,175
91 Bonneville LE  305,279        

Don't know, but as somebody who rents lots of cars, it
drives me nuts because I never know where the thing is
and although the choice should be 50-50, I seem to
pick the wrong side about 80 percent of the time.