Definition – A rationale
comprises a set of reasons or a logical basis for a course of action, strategy or measure.
Relevance to SUMP – An adopted SUMP should be based on a robust base of evidence and a rationale that supports the mobility strategy and the individual mobility measures proposed. The participation and appraisal processes will enable public authorities to construct this rationale as they work through the plan preparation stages.
Source: Oxford Dictionaries (online)