The airport was designed in the 1960s to allow for people to park next to their gate and make a short walk to their plane. However, modern security requirements and the hub-and-spoke system have made its long narrow semi-circular terminals somewhat inefficient. Recent improvements including a people-mover tram system (inside security) and renovated terminals have overcome this challenge to make DFW a great connecting airport. Also, the terminal layout with 4 semi-circular terminals and 1 squared one means that the airport has multiple security checkpoints and shorter lines. The largest selection of restaurants and shops are in Terminal D, while A, B, C, and E have a few decent restaurants spread throughout. An ongoing renovation of the older terminals will improve the selection, with part of A currently complete.