How far can you go on a tank of gas? If you said 12,665 miles, then you must own a record-breaking concept car.

The rest of us mere mortals have to contend with whatever’s commercially available, right? But as my family discovered on a recent road trip, there are some great non-hybrid options out there right now.

If you’re willing to go diesel.

The first leg of our trip — from Orlando to the Outer Banks of North Carolina — was 763 miles.

I couldn’t believe it, but we made it on a single tank in our rented Volkswagen Jetta TDI.

Fuel mileage may not be the sexiest subject, but it’s something almost everyone worries about — even with falling gas prices.

(Think about it. If I’d told you a decade ago that we’d be happy when fuel prices fell below $3 a gallon, you’d think I was off my rocker. In July 2002, a gallon of unleaded gas cost $1.43 and we were all driving SUVs. Ah, the good old days!)

The scariest part about driving a diesel car is that it’s a diesel car. Not every gas station can accommodate your fuel needs. AAA’s TripTik app came in handy because it identifies which stations carry diesel in addition to offering fuel price comparisons.

It wasn’t just the idea of running out of fuel that worried us. It was also the fear of putting the wrong kind of gas in the car. Unleaded fuel can seriously damage your engine. In fact, my sister ruined a perfectly good truck by doing this.

Fortunately, there’s a special filler cap you can attach to your fuel nozzle that’s supposed to prevent such accidents. But even with it, you still have to wonder.

At a gas station in Maryland, a trucker asked me if I was “sure” my rental car was a diesel. “Runs awfully quiet to be one,” he added.

I told him that I was sure, but having a little trouble deciding which grade of diesel I needed. He helped me sort things out.

We made it all the way up to Maine and back down to Florida — 4,294 miles — on just a few tankfuls of fuel. It probably cost us 30 percent less than if we’d driven our 2005 Honda Accord (which also gets terrific gas mileage, but not that good).

Finding these cars to rent may be the most difficult part. The woman at the Hertz rental counter said this was the first time she’d ever seen a clean diesel vehicle at her location.

After driving one for the past month, I’m seriously considering getting one. Over the lifetime of the vehicle, we could save serious money on fuel — as long as we can find a place to buy it.