1. 1) Ministry of Land, Infrastructure, “Transport and Tourism, Road Statistics Annual Report 2018,” (2018).
2. 国土交通省，”道路統計年報2018，” (2018) ．
3. 2) Japan Asphalt Mixture Association, “Asphalt Mixture Material Statistics Annual Report 2017,” (2017).
4. 一般財団法人日本アスファルト合材協会，”アスファルト合材統計年報 平成29年度，” (2017) ．
5. 3) Kanou, T., Akiba, S., Kanou, Y., Yuzawa, S., Tayu, F., J. Jpn. Soc. Civil Eng., 71, (3), I–73 (2015).