Commercial driving is a complex multifaceted task influenced by drivers' personal traits and external contextual factors, such as weather, traffic, and road conditions. Current intelligent commercial driving assessment systems only focus on the manner by which drivers operate vehicle controls when analysing driving performance and the impact of driver behaviour on road safety, potentially producing incomplete and unfair assessments. In this paper, we introduce a stakeholder co-designed approach to complement current driver-assessment systems and provide more context-aware, comprehensive and we hope--fairer assessments of commercial driving. The approach engages key stakeholders in the commercial driving sector to capture the impact of personal traits and external contextual factors on driving performance and provides a systematic approach to embed this knowledge into the assessment of commercial drivers. We demonstrate the effectiveness and utility of the approach by illustrating its end-to-end deployment in the context of heavy goods vehicle driving assessment.