Roadside breath-test surveys (RBTS) were conducted on weekend nights over 41/2 years in three United States communities to detect changes in driver blood alcohol concentrations (BACs). The observed BAC declines could have stemmed from driver avoidance of the RBTS sites. Results showed declines in cars passing RBTS sites and changes in participant demographics consistent with a lower alcohol consumption population (i.e., more women, increased age, more married drivers, fewer reported drinks per drinking occasion). Through Structural Equation Modeling, it was determined that changing driver characteristics explained only part of driver BAC declines, leaving open the possibility that driver BACs actually declined.