Knight Transportation, Inc., together with its subsidiaries, operates as a short to medium-haul truckload carrier of general commodities primarily in the United States. The company operates in five segments: Dry Van Truckload, Temperature-Controlled Truckload, Port Services, Brokerage, and Intermodal Services. It provides asset-based dry van truckload, temperature-controlled truckload, and dedicated truckload services; and drayage services between ocean ports or rail ramps, and shipping docks. The company also offers non-asset-based services, including rail intermodal and truckload brokerage services. As of December 31, 2012, it operated 3,627 company-owned tractors, as well as had 507 tractors under contract that are owned and operated by independent contractors. The company's trailer fleet comprised 9,564 53 -foot long trailers, including 1,092 temperature-controlled trailers. Knight Transportation, Inc. was founded in 1989 and is headquartered in Phoenix, Arizona.