 The facilities support air, highway, railroad, pipeline, water, and even space transportation.The design aspects of transportation engineering include the sizing of transportation facilities (how many lanes or how much capacity the facility has), determining the materials and thickness used in pavement designing the geometry (vertical and horizontal alignment) of the roadway (or track).Before any planning occurs an engineer must take what is known as an inventory of the area or, if it is appropriate, the previous system in place.