Purpose–Capability–Condition: A Three-Axis Framework for Comparing Forest-Road Classification Systems

Forest-road classification systems are not internationally aligned, and no common basis exists for comparing them. This study specifies a three-axis analytical framework—functional purpose, engineering capability and service condition—and applies it to the operative legislation, regulations and engineering manuals of six jurisdictions: Japan, the United States, British Columbia (Canada), New Zealand, Sweden and the Republic of Korea. The framework is defined a priori; each jurisdiction was coded on eight dimensions and aggregated to the three axes. No universal numbered grade system was found; existing numbered categories are not equivalent. Functional purpose and engineering capability are each recorded as an independent road attribute in five of the six jurisdictions; service condition in only three. Where it is not, condition is not absent but held in a form that cannot be read off the road: Japan rates individual structures without carrying the rating on the road record, New Zealand derives maintenance priority from road class, and Korea logs repairs without recording a state. Capability and condition are interpretable only where verified over a complete route or a defined segment. The framework is a diagnostic instrument rather than a classification system, demonstrated here for the Republic of Korea.