Over time, road usage in western North Dakota has changed. Interstate, highway, and low-volume unpaved roads have been used with greater frequency because of increased agricultural production and a growing energy sector. This evolution is especially evident in a 17-county region where oil extraction methods have recently improved production economics. Roads once used only for local access and agricultural purposes are now being used at high volumes to serve expanding oil production. Oil companies, oil workers, commercial trucks, and industrial equipment associated with oil and gas development all use these roads to access oil drilling and production sites. This has led to not only an increase in the traffic volume, but an increase in the number of overweight and oversized vehicles on the road as well. As a result, a number of roads are in poor condition and many others are deteriorating rapidly.