Background: Driving licensing jurisdictions require detailed assessments of fitness-to-drive from occupational therapy driver assessors (OTDAs). We developed decision training based on the recommendations of expert OTDAs, to enhance novices' capacity to make optimal fitness-to-drive decisions. The aim of this research was to determine effectiveness of training on novice occupational therapists' ability to make fitness-to-drive decisions. Methods: A double blind, parallel, randomised controlled trial was conducted to test the effectiveness of decision training on novices' fitness-to-drive recommendations. Both groups made recommendations on a series of 64 case scenarios with the intervention group receiving training after reviewing two thirds of the cases; the control group, at this same point, just received a message of encouragement to continue. Participants were occupational therapy students on UK and Australian pre-registration programmes who individually took part online, following the website instructions. The main outcome of training was the reduction in mean difference between novice and expert recommendations on the cases. Results: Two hundred eighty-nine novices were randomised into intervention; 166 completed the trial (70 in intervention; 96 in control). No statistical differences in scores were found pre-training. Post training, the control group showed no significant change in recommendations compared to the experts (t(96) = -.69; p =.5), whereas the intervention group exhibited a significant change (t(69) = 6.89; p < 0.001). For the intervention group, the mean difference compared with the experts' recommendations reduced with 95% CI from -.13 to.09. Effect size calculated at the post-training demonstrated a moderate effect (d =.69, r =.32). Conclusions: Novices who received the decision training were able to change their recommendations whereas those who did not receive training did not. Those receiving training became more able to identify drivers who were not fit-to-drive, as measured against experts' decisions on the same cases. This research demonstrated that novice occupational therapists can be trained to make decisions more aligned to those of expert OTDAs. The decision training and cases have been launched as a free training resource at www.fitnesstodrive.com. This can be used by novice driver assessors to increase their skill to identify drivers who are, and are not fit-to-drive, potentially increasing international workforce capacity in this growing field of practice.