The metropolitan area generally refers to a region including a large city and its adjacent areas. Various activities such as transportation and industry, including commuting, cross the boundaries of administrative districts and create spatial ranges of their influences. For this reason, metropolitan areas have been designated based on various criteria to establish policies based on reality. Considering the most recent 2020 National Traffic Survey and its geographic scope, this section describes five metropolitan areas (Seoul Metropolitan Area, Chungcheong Region, Gangwon Region, Honam Region, and Yeongnam Region).