The times have certainly changed for the sport utility market. While SUVs enjoyed tremendous sales success in recent years, the rising price of gasoline coupled with a weakened economy has driven down SUV sales more recently.

"The day after 9/11, I began changing my habits for the better and ever since then I've looked for methods to improve fuel economy," Gerdes told LiveScience. "We all have our trigger points — mine was global security."

Authorities have reopened Colorado's main east-west highway but say it may be days before investigators are able to sort out the chain of events in a pileup involving 60 to 75 vehicles.