Objective: This research investigated the on-road driving performance of individuals with ADHD across a range of road and traffic conditions to determine whether errors were linked to situational complexity and attentional demands. Method: The everyday driving performance of medicated drivers with ADHD, unmedicated drivers with ADHD, and controls was tested in urban, residential, rural, and highway environments using driver license testing procedures. Results: Unmedicated drivers with ADHD displayed fewer safe driving skills and committed more inattentive and impatient driving errors, particularly in low demand highway and rural driving conditions. Medicated drivers’ performance was not reliably different than controls. Participants in both ADHD groups were more likely than controls to report risky driving and involvement in crashes. Conclusion: The results demonstrate that situations with low attentional demand are particularly risky for unmedicated ADHD drivers and suggest that focus on these situations may be useful in improving driving outcomes for this population.