Both the environmental and safety costs of road transport are considered to be unacceptably high. The ‘Foot-LITE’ project aims to encourage drivers to adopt greener and safer driving practices, with real-time feedback being given in-vehicle (during driving) and retrospective feedback off-line (pre- and post-driving). This article focuses on the early concept development of the Foot-LITE system, for which a Cognitive Work Analysis methodology was adopted. Presented are results from a Work Domain Analysis (WDA) conducted to scope the relevant driving domain and to identify the constraints on the system. Besides establishing a common framework and language for the project, the process will ultimately contribute to the design of the in-vehicle interface. This article also suggests an extension to the WDA framework to include novel methods for assessing the priority of lower level nodes and contributions of these nodes to the high-level objectives of the system.