Retractable bridge

A retractable bridge is a type of movable bridge in which the deck can be rolled or slid backwards to open a gap while traffic crosses, usually a ship on a waterway. This type is sometimes referred to as a thrust bridge.

Retractable bridges date back to medieval times. Due to the large dedicated area required for this type of bridge, this design is not common. A retractable design may be considered when the maximum horizontal clearance is required (for example, over a canal).