11/18/2005 Dr. Paul Jovanis, professor of civil engineering who led the Penn State study, says, “Our analysis of data from three national trucking companies during normal operations in 2004 shows that the crash risk is statistically similar for the first six hours of driving and then increases in significant steps thereafter. The 11th hour has a crash risk more than three times the first hour.”

Jovanis described the findings in a paper,