Why are all train bridges called trestles and not just bridges? On the other hand, why are motor vehicle bridges that have the characteristics of a trestle, considered a bridge? Example: Dames Point Bridge in Jacksonville Florida. Parts of the bridge have a horizontal beam that is supported by a pair of sloping legs. Yet, it is considered a cable-stayed bridge. Does it have to be wooden to be considered a trestle as well? Are there motor vehicle bridges that are trestles still in use today?