The National Highway and Traffic Safety Administration has put the smart fortwo through its New Car Assessment Program, and the results are mixed.

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In the frontal impact crash-test, smart USA's micro-compact 1,800-pound vehicle received a four-star rating for driver safety, but only three stars for the passenger side. This means there is a 21 percent to 35 percent chance of serious injury for the person in the right seat during a 35-mph head-on collision, compared to an 11 percent to 20 percent chance for the one behind the wheel.

There is good and bad news for smart in the results of the side-impact test, as well. With only a 5 percent chance of an occupant suffering serious injury when the car is hit directly from the side at 38.5 mph, the fortwo scored the highest rating, five stars; however, a "safety concern" was added to that result because the driver-side door of the fortwo opened during the test.

The NHTSA warns that an open door can increase the likelihood of a passenger being ejected from the vehicle. The NHTSA does not deduct from the star rating for issues not directly related to the calculation of those results, but when certain vehicle components fail during the test, such as a door opening or fuel leaking, a "safety concern" is noted.

In the rollover test, which indicates how well an automobile will fare when involved in a single-vehicle crash, the fortwo received a three-star rating, which is low for a car, and more commonly given to large, top-heavy trucks. The fortwo’s overall shape likely is to blame for its poor showing in this test, as it is nearly as tall as it is wide.