ABSTRACT:BACKGROUND(#br)Driving/riding under the influence (DUI) of alcohol is a major public concern worldwide. Only a few studies have distinguished DUI-related variables between motorcyclists and car drivers. This study examined the differences in demographic characteristics and drinking behaviors among first-time DUI offenders operating different transportation vehicles, and risk factors for frequent DUI (fDUI) among them.(#br)METHODS(#br)We conducted an anonymous survey for 561 first-time DUI offenders who attended a mandatory educational program. Participants self-administered questionnaires concerning alcohol drinking behaviors and DUI. We defined fDUI as at least two DUI behaviors per month based on self-reported information. Demographic and drinking characteristics were compared between DUI offenders, car drivers and motorcyclists. Logistic regression analysis was used to examine risk factors for fDUI.(#br)RESULTS(#br)Two-thirds of first-time DUI offenders were motorcyclists. Compared with car drivers, motorcyclists were younger and less educated, with a higher percentage of them being women and unmarried. Car drivers reported a higher rate of fDUI than motorcyclists (16.5% vs. 9.7%). Regression analysis revealed that binge drinkers had a higher fDUI risk in both groups. Regarding the drinking place prior to DUI behavior, workplace was significantly associated with fDUI in car drivers.(#br)CONCLUSIONS(#br)Distinct strategies may be required for motorcyclists and car drivers for DUI recidivism prevention, and drinking place interventions should also be considered.