1. American Association of State Highway and Transportation Officials (AASHTO), 1994.
2. American Association of State Highway and Transportation Officials (AASHTO), 2004.
3. Prediction of the service life of warning signs;Awadallah;Public Roads,1988
4. Gap acceptance at atypical stop-controlled intersections;Gattis;Journal of Transportation Engineering,1999
5. Harwood, D., Mason, J., Brydia, R., Joubert, H., Lamm, R., Psarianos, B., 1995. International sight distance design practices. In: Proceedings of the International Symposium on Highway Geometric Design Practices, Boston, MA, USA.