Abstract
A few cases filed as litigation are indicating the importance of assuring the justification of planning decision in the field of transportation planning in Japan. In the paper, the justifiability of planning procedure is defined by six elemental conditions to be satisfied during the process. Those six elements are legality, fairness, procedural objectivity, procedural rationality, procedural integrity and procedural validity. The procedural validity is ideally conditioned by the inter-subjective social approval for the planning process. The procedural validity is assumed to be composed of four elemental conditions: transparency, accountability, dialogic sufficiency and acceptability to governmental reactions. The paper discusses on the structure and those elemental conditions and eventually concludes the appropriateness of the structure of procedural justifiability proposed in the paper.