Roads increase the output of commerce and can be built in any terrain except water squares. Also, units moving along roads expend one third of a movement point per square, regardless of terrain type. Terrain Produces Floodplains 1 commerce, 2 with a road. Grasslands 0 commerce, 1 with a road. Plains 0 commerce, 1 with a road. Hills 0 commerce, 1 with a road. Mountains 0 commerce, 1 with a road. Forests 0 commerce, 1 with a road. Jungles 0 commerce, 1 with a road. Workers are ordered to build roads by pressing R or the "Build Road" button.