Touring After the Apocalypse, Vol. 3 by Sakae Saito

Youko gets a message from her sister, sending Airi and her off to Tsukuba, a city of research and universities. Then, after a stop to stretch their legs at Lake Kasumigaura, the two find themselves at Motegi Mobility Resort-a motorsport mecca with tons of well-preserved bikes!
Binding: Paperback / softback