A few days ago, we reported that automakers were looking at next-generation materials in an effort to reduce the weight of cars, and thus help them improve fuel economy. Now some automotive engineers are pointing out that this may have a detrimental effect on crash safety.

The issue is fairly straightforward. In a crash, a more massive car will transmit more force to a less massive car. If you’re riding in the lighter car, you will absorb more of the impact. That’s basic physics.

One of the advantages of metal cars is that you can engineer metal to crumple and give way throughout the fraction of a second that covers a collision. You can compare the effect to stomping on a piece of concrete versus stomping on a soda can. The can crumples, while the concrete hurts your foot.

In a survey conducted by Wards Automotive, automobile engineers stated that they believe the 2025 CAFE standards will make cars more alike, smaller, more expensive, and less safe. However, there is substantial disagreement, with many engineers believing that advances in design and technology will make up the necessary distance between today’s cars and the 2025 standards.

Our view is that it’s certain that cars will be different, and likely that they will be smaller. But people will always demand cars that are distinctive and fun to drive, and the company that provides those cars will succeed in the next 15 years.