(Brian Fung/The Washington Post)

The first thing you notice about Toyota's hydrogen fuel cell SUV is that you hardly feel like you're driving. It's more like you're floating. When the engine kicks in, you don't get the jolt that you do with a car that runs on gasoline. It's not even like a typical hybrid, which starts you off on battery power before handing you off to the fossil-fuel engine.

Instead, the converted Highlander I drove to my dentist Friday morning was a hybrid of a different kind. A nickel-metal hydride battery still got the car moving from a standstill, but where an ordinary engine would sit under the hood, burning up dead dinosaurs, was an electric motor hooked up to four tanks holding 5 kilos of hydrogen gas.

Unlike with ordinary cars, the fuel isn't burned. It's passed through a membrane that turns the hydrogen gas into water — a process that draws on outside air to create electricity for the engine. Fuel cell technology sounds like science fiction. But it's coming very soon to the mass market: Hyundai has plans to introduce a commercial fuel cell vehicle as early as this year, and Toyota will debut its hydrogen-powered car in 2015.

(Brian Fung/The Washington Post)

I took the Highlander through the small, neighborhood streets of Northwest Washington, before dropping down into Rock Creek Park and opening up the throttle. In the tight spaces of Columbia Heights, the regenerative braking system seemed a little overeager, responding to a tap of the foot with more stopping power than I expected. Going up steep hills proved no problem, with the electric engine's steady hum providing a more genteel kind of feedback than a combustion engine's aggressive roar.

Instead of a tachometer on the left side of the instrument panel, there's an electricity meter that tells you how much power you're drawing. It's a little hard to grasp, because unlike a typical engine, there's no optimal RPM range.

(Brian Fung/The Washington Post)

Complementing that is a screen-based chart that tells you how efficient your energy usage is. This will be familiar to anyone who's driven an ordinary hybrid.

(Brian Fung/The Washington Post)

Fuel economy obsessives will find lots to like about this car. On a full tank, the Highlander has a range of 300 or 400 miles, according to Chris Santucci, the Toyota engineer sitting in the passenger seat beside me. Filling up takes about five minutes — not much longer than your typical vehicle — but you can go much farther than even today's best hybrids. The Toyota Prius gets about 50 miles to the gallon; the Highlander gas-electric hybrid gets about 27 under optimal conditions. The hydrogen-based Highlander? Sixty miles per gallon.

Of course, it doesn't matter how far you can go on a single tank if you have nowhere to refuel. As critics will point out, hydrogen vehicles are limited by the infrastructure that supports them. So far, California has been the most active in building hydrogen stations. There are nine available for public use right now around San Francisco and Los Angeles, with dozens more on the way. South Carolina is the only other state with a hydrogen refueling station, according to the Department of Energy.

Building a station takes just $1 million-$2 million, according to Santucci. So that's no problem. It's the gas that's expensive. Even in the Los Angeles area, it's priced as high as $5 a kilogram. Much of the cost is linked to transporting and storing the stuff in liquid form; unless the distribution point is relatively close to the pipeline, you're going to have to pay through the nose.

(Brian Fung/The Washington Post)

This is where the relative rarity of hydrogen cars — and their fuel economy — could become an advantage. Santucci told me that, at least at first, you might not even need all the infrastructure of a traditional gas station.

"Maybe you have a truck that has refueling nozzles on it, and you park it in one spot for a time," he said. "Try a couple spots in Northwest D.C. one week, and move it to the suburbs the next."

Here's one other thing that's hard to ignore. The rise of hydrogen vehicles like Toyota's new Highlander — whose price has not been announced — is also taking place at a time when Americans' appetite for driving is on the wane. It's not clear how fuel-cell vehicles fit into this trend, precisely; they could become a kind of transitional technology in this period, easing us off cars more generally. Or if demand for driving picks up again, they might take a greater share of the market.

Right now, though, the market share targets are very modest for hydrogen cars — around two-tenths of a percent for the foreseeable future, according to Santucci.

"Gasoline's going to be around for quite some time," he said.