roll-on roll-off
adjective [ before noun ] UK uk/ˌrəʊlˌɒn ˌrəʊlˈɒf/ us/ˌroʊlˌɑːn ˌroʊlˈɑːf/ (informal ro-ro, uk/ˈrəʊ.rəʊ/ us/ˈroʊ.roʊ/)
（船）滚装滚卸的，汽车可直接上下的
A roll-on-roll-off ship is built so that vehicles can drive on at one end and off at the other.
a roll-on roll-off ferry 汽车轮渡