1/23/2012 9:54 AM ET| Safer cars can make unsafe roads The
Peltzman Effect may be debatable and hard to prove, but it
points to a disturbing trend: Drivers who feel safer in their
cars take greater risks. That can mean more crashes. Sometimes a
perfectly good theory can sound nuts. Take this one: Safer cars
make the roads less safe. Sounds as loony as the one about how
you're better off not wearing a seat belt, right? But the first
statement is, in fact, a lot more credible -- and it leads to
some interesting debate about driving behavior, accident rates
and, ultimately, how insurance rates are calculated. It's called
the Peltzman Effect, a generally accepted principle that
suggests that as people feel safer they take on greater risk.
People have a set tolerance level for risk and adjust their
behavior accordingly. Build a high-impact football helmet, and
players will ram their heads harder. Improve car safety, and
people will drive faster. The danger comes when the added risk
cancels out the benefits of the