A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. It is a complicated bridge to contsruct and relies on perfect symmetry throughout the entirety of the construction to be successful.
These bridges tend to span long distances and require a lot of materials so it is better to use wood, which is cheaper than steel. However, you can use steel to reinforce certain parts of the bridge. The most important aspect in building this bridge is the perfect symetry so you must use the Line Tracer tool in order to achieve this.