1. Comprehensive Planning Division. (2012). The statistical bulletin of the development of the highway and waterway transportation industries, Ministry of Transport, China, April, 2012.
2. Highway Bureau. (2012). 2011 National Highway Maintenance Statistical Yearbook, Ministry of Transport, China, March, 2012.
3. Highway Network Management and Emergency Disposal Center, MOT, China. (2010). Overall operation and analysis report of national trunk highway network in 2009, 18-19.
4. Malpractices, State Council, P.R. China. (2012). Implementation plan of the free passage of small passenger cars during major holidays, July 24.
5. Ministry of Transport, China. (1994). Design and Construction Technical Specification of Expressway Traffic Safety Facilities (JTJ 074-94), 10-11.