A Traffic ship (jap.: 交通船)(Baronh: ジェス Jess) is a ship used within a city in space like Lakfakalle. It's an equivalent to ancient cars within a city.
Cities located in space with many separate superstructures require a means of transportation to transport people or goods from place to place. The traffic ship is the term used for these ships. As such it's an interplanetary ship without plane-space technology. All traffic ships must be registered by the Imperial City Transportation Agency and must use designated ship lanes.
Most traffic ships are the size of boats like most shuttles. There is virtually no differences.