Bridge definition Bridge is a structure which covers a gap. It is a structure carrying a path way or road way over a depression or obstacle . Function Generally bridges carry a road or railway across a natural or artificial obstacle such as river , canal or another railway or another road. It is a structure corresponding to the heaviest responsibility in carrying a free flow of transport. It is the most significant component of transportation system in case of communication over spacing and gaps. In short bridge is the key element in the transportation system. Bridge controls the capacity of the system If the width of a bridge is insufficient to carry the number of lanes required to handle the traffic volume , it will be a constriction to the flow of traffic. If the strength of a bridge is deficient and unable to carry heavy trucks, load limits will be posted and truck traffic will be rerouted. Hence it controls both the volume and weight of the traffi...