An estimated 3.1 million Americans have become what researchers call "extreme commuters" - People who travel more than 90 miles to work each way.

"People think I'm crazy. They don't know how I do it," said Adrienne Procopio, 22, who graduated in May from Central Michigan University and works as an account executive for a company 90 minutes away from her parents' house in downtown Detroit. She saves money living at home, despite the $120 she spends each week to fill up her car.

However, studies show that extreme commutes can have several public health and safety implications. In addition, commute time is the second-biggest factor in sleep deprivation, which can cause health problems, memory loss and attention deficits, all of which can affect job performance.

As a Detroit Free Press story on Page M3 explains, commutes tend to increase during periods of joblessness and belt-tightening, when people increase the radius of their job searches.