DENVER, CO - OCTOBER 02: Traffic drives on the segement of Interstate 25 near the venue for the first presidential debate on October 2, 2012 in Denver, Colorado. The Interstate will be closed from 5 PM until 10 PM when Republican presidential candidate Mitt Romney will square off against U.S. President Barack Obama in the first of three debates on October 3. (Photo by Doug Pensinger/Getty Images)

DENVER, CO - OCTOBER 02:  Traffic drives on the segement of Interstate 25 near the venue for the first presidential debate on October 2, 2012 in Denver, Colorado. The Interstate will be closed from 5 PM until 10 PM when Republican presidential candidate Mitt Romney will square off against U.S. President Barack Obama in the first of three debates on October 3.  (Photo by Doug Pensinger/Getty Images)