In terms of the materials used in the construction of vehicles in General, it often choose to use the existing material is primarily local in order to save the expense of transport material from sources far away.
In terms of the materials used in the construction of embankment, they generally tend to use primarily local materials available in order to save the cost of transporting materials from sources far away.
In terms of the materials used in construction vehicles that are generally choose to use existing materials local, primarily to save transportation costs, material from sources far away.