The Utah Department of Transportation (UDOT) keeps the Salt Lake State rolling. Besides maintaining some 5,900 miles of roadway, UDOT provides a variety of other transportation services. The department's Traffic Management Division manages more than 600 coordinated traffic signals and other statewide traffic operations. The Traffic and Safety Division tries to prevent roadway accidents through several programs, including the replacement of metal guardrails with crash cushions. Motor Carrier Services operates 10 ports of entry for commercial trucks and enforces regulations for such vehicles. Off the roadways, UDOT licenses airports and provides aircraft for state use, among other aviation-related operations.