Roll on / Roll off (Ro/Ro)

A Roll-On/Roll-Off (RO/RO) ship is specifically designed to carry wheeled and tracked vehicles as all or most of its cargo.

Vehicles are driven on and off the ship by means of the ship's own ramps and are safely stowed and secured under deck.  Below-deck space and volume utilization is more efficient than on a containership, because RO/RO Carrier’s are designed to accommodate cargoes which cannot be stacked but which vary in height.  

RO/RO ships are commercially viable and the new car Manufacturer’s prefer RO / RO shipping for new automobiles that are transported by ship around the world.

By rolling cargo on board these vessels and rolling it off at its destination, shippers can reduce the number of times their cargo is handled, thus reducing the risk of damages.

Since 1970 the market for exporting and importing cars has increased dramatically and the number and type of RO/ROs has increased also. In 1973, Japan’s K Line built the European Highway, the first Pure Car Carrier (PCC), which carried 4,200 automobiles. Today’s pure car carriers and their close cousins, the Pure Car/Truck Carrier (PCTC) are distinctive ships with a box-like superstructure running the entire length and breadth of the hull, fully enclosing and protecting the cargo. They typically have a stern ramp and a side ramp for dual loading of many thousands of vehicles, as well as extensive automatic fire control systems.
The PCTC has liftable decks to increase vertical clearance as well as heavier decks for "high and heavy" cargo. A 6500 unit car ship with 12 decks can have three decks which can take cargo up to 150 tons with liftable "panels" to increase clearance from 1.7 meters to 6.7 meters on some decks.  
With the building of the car carrier Faust, by Wallenius Wilhelmsen out of Stockholm, in June 2007 the car carriers entered a new era called the LCTC (Large Car & Truck Carrier)