My first job was pumping gas at regular neighbour gas station and one day a semi rolled in because he was low on gas. He insisted that we use both diesel pumps on the pump so that it would take faster and it still took forever. I can't remember if he filled both side of his truck but if he did that would have required him to go around the island to get the other side tank.

I've only been to a cardlock station a few times but the pumps seem like regular pumps.

I just looked it up and apparently regular gas station pumps in Canada are limited to 38 L/min (10 US gal/min) but some cardlock stations can have larger pumps with a higher rate on them.

If a semi truck has two saddle tanks that's 200-300 gallons, but some trucks can apparently carry more? I'm not an expert on this, But I can reach out to a friend who owns a crane and trucking company if someone else doesn't chime in with a more detailed response.

So at 200-300 gallons and 10 gallons per minute it can take 20-30 minutes to fill a truck.