In Nigeria, commercial motorcycle operation is facing a serious challenge with respect to regulation. Policies and other interventions to improve the operation of this mode, in particular with respect to safety, have not been successful mainly due to poor enforcement. For the system to improve, behavioural changes are required from the drivers with regards to adherence to law. This paper uses system dynamics to identify factors that affect drivers’ compliance to law and how these factors can be swayed to improve compliance, and thus safety. A causal loop diagram is developed from interview data obtained from a survey conducted with stakeholders in Nigeria and formalised into a quantitative stock and flow model using secondary data obtained from multiple sources. Results from model simulation suggest that the harsh operating condition drivers are subjected to due to their “illegal” operating status contributes to their compliance difficulty. It also found that under a corrupt transport system such as in Nigeria reliance on an enforcement agency alone to improve compliance may not achieve any substantial improvement. This paper concludes by providing some policy recommendations on how compliance can be improved in commercial motorcycle operation. Improving safety enforcement would protect vulnerable road users and provide co-benefits to reduce other externalities of transport, e.g., through stricter adherence to speed limits. These recommendations might also be useful for enforcing emission regulations in future.