What does the term 'should' imply in roadway design guidelines?

The term 'should' in roadway design guidelines indicates advisory guidance. This means that while the recommendations are intended to promote best practices in roadway design, they are not strictly mandatory. Instead, they provide a framework that practitioners can follow, but they retain the flexibility to deviate as long as the overall objectives of safety and efficiency are met. This allows for professional judgment to play a role in the decision-making process, accommodating unique site conditions or specific project requirements. Consequently, the use of 'should' signifies that applying the guideline is strongly encouraged, but not obligatory, distinguishing it from terms that imply mandatory actions or prohibitions.