Squeezing safety into small cars

With competition for small cars heating up, engineers are finding new ways to make them safer.

There's no denying physics. All things being equal, a larger, heavier vehicle will protect its occupants better in a crash than a smaller, lighter one. For this reason, front crash tests can only be compared between cars of similar size and weight.

But larger, heavier vehicles require more energy - and therefor more fuel - to move. The physics of fuel economy are at odds with the physics of safety.

If you're shopping for a small car to save gas, it's especially critical to look for one with every safety advantage possible, says Adrian Lund, president of the Insurance Institute for Highway Safety.

"It becomes even more important that its crash results are really good," Lund said of small cars.

Honda, Subaru and Volvo are three automakers with particularly strong safety records, as judged by the percentage of their vehicles that get top crash test ratings. Their small cars offer a glimpse of how all small cars can be made as safe as possible.

Meanwhile, Daimler's Smart division, a newcomer to this market, needs to convince buyers that its ultra-tiny ForTwo is as safe as other small cars.

NEXT: Body structure