Poor crash test numbers might seem to be expected with a vehicle as tiny as the Smart Fortwo, but Daimler – its manufacturer – has consistently claimed the Smart was designed to get a four star safety rating on crash tests.

However, in National Highway Traffic Safety Administration testing, as reported in the Detroit Free Press, the Smart’s front crash test rating was not four stars, nor five stars – the best possible rating.

It was three stars.

That’s one of the lowest ratings of any passenger vehicle on sale in America and a rating which equates to a 21% to 35% probability of serious injury in the test standard 35 mph collision. (Technically, the rating was four stars for the driver and three for the passenger.)

(more after the jump)

Actually, the risks are probably much higher than the NHTSA test scores suggest, as the nature of the agency’s tests excludes vehicle size as a factor in crashworthiness. The nature of the barrier testing used postulates that the collision is between vehicles of the same size. In the case of the Smart, however, that’s unrealistic, because there is almost no other vehicle on the road that’s the same small size. The newspaper quotes the Insurance Institute for Highway Safety as authority for the obvious: that in a collision with a larger vehicle, occupants of a smaller vehicle are more likely to be injured.

The Smart did better in side crash testing, scoring five stars, but even that distinction is dubious: the doors popped open. That raises the risk that an occupant would be ejected during a collision.

The only other car with a front crash test rating as low as the Smart Fortwo is another import: the 5 Series BMW. The Smart has fared better in European crash testing, where it the equivalent of four out of five stars, and the domestic distributor of the vehicle said that the NHTSA test results were “expected.” That statement, however, was not consistent with the claim that the vehicle would meet the four star rating.

The bloom may be off the rose for the Smart, just as it begins its process of introduction into the United States market. The diminutive size of the vehicle has always suggested that crash safety would be a large issue in the U.S., even though the importer had sought to dispel those concerns by publicizing the results of earlier European crash tests.

Furthermore, early reviews of the car have faulted its performance and handling. One particularly devastating review received almost a full page in the Wall Street Journal in the past week. The newspaper review faulted the Smart for being underpowered, riding poorly, and not shifting smoothly, concluding that it was a car with limited real world capabilities that would disappoint many potential buyers, particularly at its rather lofty price.