It shouldn't take a government or industry study to prove the obvious, but a report from the Insurance Institute for Highway Safety (IIHS) has confirmed what mostly everyone already knows: small cars can be dangerous to your health, even deadly. Yes, if you took physics then you know that when two objects moving at the same speed hit each other, the one that weighs less will suffer more damages.

The IIHS study comes just as some consumers are considering moving to smaller vehicles in a bid to save on gas and/or to reduce their so-called carbon footprint. Smaller, lighter vehicles can return improved fuel economy, but those changes could come at the expense of occupant safety.

"There are good reasons people buy minicars," says Institute president Adrian Lund. "They're more affordable, and they use less gas. But the safety trade-offs are clear from our new tests. Equally clear are the implications when it comes to fuel economy. If automakers downsize cars so their fleets use less fuel, occupant safety will be compromised. However, there are ways to serve fuel economy and safety at the same time."

The IIHS did not pair up small cars with pickup trucks and sport/utility vehicles when conducting their study nor did they choose vehicles from different manufacturers. When a subcompact car was chosen from one manufacturer the IIHS chose a slightly larger vehicle from that same car company.

For example, the IIHS crashed a Toyota Yaris into a larger Toyota Camry; a smart fortwo into a Mercedes-Benz C-Class (both made by Daimler); and a Honda Fit into a Honda Accord. Each vehicle was traveling at 40 miles per hour. All three small cars performed poorly, while the larger vehicles were rated good or acceptable. The small cars tested, however, receive good ratings in government-conducted crash tests with fixed barriers.

All three small cars performed well in government barrier tests where they are rammed into a stationery object. However, when meeting “head on” with a larger vehicle, the results were obvious and would be catastrophic for human occupants.

What should the IIHS study do for people shopping for a new or used car? Consider the law of physics, that's what. Short term savings in fuel economy could prove dangerous in a crash, even deadly.