[10] An artificial island, Umihotaru (海ほたる, Umi-hotaru, "sea firefly," referring to Vargula hilgendorfii), marks the transition between the bridge and tunnel segments and provides a rest stop with restaurants, shops, and amusement facilities.

The Tokyo Bay Aqua-Line shortened the drive between Chiba and Kanagawa, two important industrial areas, from 90 to 15 minutes,[11] and also helped cut travel time from Tokyo and Kanagawa to the seaside leisure spots of the southern Bōsō Peninsula.

An explicit goal of the Aqua-Line was to redirect vehicular flow away from central Tokyo, but the expensive toll has meant only a limited reduction in central-Tokyo traffic.

[13] At opening time, the roadway had the highest toll fee in Japan – a one-way trip costs ¥5050 or ¥334 per kilometer.

[12] Due to its expensive toll, analysts see lower traffic volume than what Japan Highway Public Corporation, the operator of the roadway, expected at 25,000 cars.