This study examined how illicit drug users perceived roadside drug testing (RDT) in Queensland, a jurisdiction that enforces a zero-tolerance enforcement strategy to drug driving. Fifty-two illicit drug users were interviewed, and thematic analysis was used to identify emerging themes. The results showed that exposure to RDT and apprehension certainty were reportedly low. The targeted regime of RDT had dichotomous implications towards apprehension certainty, due to the familiarity with the testing procedures. Participants also reported mixed experiences with testing accuracy, in that some offenders reported testing negative just following use, while others who reportedly regulated their driving tested positive, despite not having recently used. Next, participants reported engaging in punishment avoidance behaviours that aimed to evade police exposure and suspicion, and to mask the presence of drugs in their saliva. The combination of avoidance behaviours and perceptions of one’s ability to circumnavigate RDT impacted on participants’ apprehension certainty. Due to their experiences, the majority of (cannabis) users agreed that RDT approaches were discriminatory and unjust, due to the zero-tolerance policy, the testing of presence over impairment, and the lack of policing towards other drugs. These perceived limitations were noted to potentially increase user offending in some circumstances and suggested that there may be a dissonance between the intended aim of RDT and the outcome on drug user behaviours. The findings of this study may hold implications for future research in identifying limitations in the current evidence and help inform policing procedures and policy surrounding future drug testing approaches.