“…Deterrence research has important implications in traffic safety policies, and many studies have focused on the offense of DUI (e.g., Hagen, 1977;Salzburg, 1981;Ross and Gonzales, 1988;Zador et al, 1989;Sadler, 1991;Lund, 1993;DeYoung, 1997;Grosvenor et al, 1999;Piquero and Pogarsky, 2002;Helander, 2002;Briscoe, 2004;Clapp, 2005;Cherry, 2006;Freeman et al, 2006;Fiorentino et al, 2007;Webster et al, 2008). Some of the studies found that the certainty, not the severity, of the punishment is related to drinkingand-driving behavior or DUI convictions (e.g., Ross, 1984Ross, , 1992Piquero and Pogarsky, 2002;Clapp, 2005).…”