How small is too small? Smart, it seems, may have pushed the envelope a bit too far. Measuring barely 8 feet nose-to-tail, the fortwo microcar is, without question, the smallest mass-market product on U.S. highways. It defines a new generation of so-called “urban commuter cars.”

We’re a nation that has long equated bigger with better, and nowhere is that more true than in the auto industry, where a car’s worth is normally measured by the pound and inch.

But as our roads grow more crowded, fuel prices rise and tough new emissions standards go into effect, even American motorists are beginning to appreciate downsized models like the Mini.

So, how small is too small? Smart, it seems, may have pushed the envelope a bit too far.

Measuring barely 8 feet nose-to-tail, the fortwo microcar is, without question, the smallest mass-market product on U.S. highways. It defines a new generation of so-called “urban commuter cars.”

The fortwo does indeed provide seating for two, with a modest bit of storage space in back. There’s a hardtop version, as well as a sort-of convertible, which features a trick fold-back canvas top that provides a more open driving experience than a conventional sunroof.

For those used to big SUVs, driving a Smart fortwo could be a daunting experience. It’s nearly small enough to fit into the back of a Cadillac Escalade or the cargo bed of a Ford F-150. So, it’s not surprising it’s more suited to driving around on local roads rather than the interstates, where it does tend to be buffeted around as 18-wheelers blow by.

The extremely short wheelbase makes you feel more like you’re climbing over, rather than simply jouncing across, a speed bump. Nonetheless, after spending a few hours behind the wheel, there’s something pleasant about the driving experience. It’s got the sort of maneuverability of a go-kart, letting you dart in and around obstacles with ease.

Of course, it would help to have a bit more power. Despite its size, the 70 horsepower coming out of the car’s engine still feels a bit anemic. Our bigger complaint has to do with the Smart fortwo’s electrically shifted manual gearbox. It’s just not up to the job, delivering bone-jarring shifts and taking a fair amount of time to do so.

The other problem is fuel economy. On the positive side, you get 33 miles per gallon around town and a full 41 on the highway for those willing to take to the interstates. But considering the size of this two-seater, it just doesn’t seem like quite enough, not when even some compact four-doors are starting to push into the mid-30 mpg range and hybrids are well into the 40s.

The Smart fortwo has a number of flaws, yet there’s something that’s still fun about it, all the more so if you’re looking for something small and nimble to run in-town errands. With a few updates, this could be a truly significant offering, one that would define the urban commuter car.

Paul A. Eisenstein is an award-winning journalist who has spent more than 30 years covering the global auto industry. His work appears in a wide range of publications worldwide, and he is a frequent broadcast commentator on subjects automotive.

2010 Smart fortwo

Engine: 70-horsepower, 1.0-liter inline-three-cylinder

Manufacturer’s suggested retail price: $12,635

Cost fully loaded: $18,000 (fully-loaded Smart fortwo Passion Convertible)