"There are only so many minutes and miles in a day that people will travel," Schipper explained in an interview on the Stanford campus. Schipper, former director of research for the World Resources Institute's Center for Sustainable Transport (known as EMBARQ), believes higher fuel prices play only a part in what is happening.

"There are only so many minutes and miles in a day that people will travel," Schipper explained in an interview on the Stanford campus. Schipper, former director of research for the World Resources Institute's Center for Sustainable Transport (known as EMBARQ), believes higher fuel prices play only a part in what is happening.