[zmgsabst]

I’m not sure I’ve ever seen one that was one-way; but my experience is limited to US, MY, TH, and VN.

In those four at least, traffic can come from either direction so you can have left-handed fills use both sides of a pump.

[devilbunny]

Costco and Sam's Club usually have their filling stations set up for one-way traffic, but offhand those are the only ones I've seen that way in US, Canada, Caribbean, and western/central Europe (though the Euro design of filling stations just off the highway encourages one-way traffic, it doesn't mandate it). Haven't driven myself elsewhere.