1. U.S. Federal Highway Administration 2009 http://safety.fhwa.dot.gov/intersection/unsignalized/presentations/unsig_pps_041409/long.cfm
2. Marek MA Access Management Manual [Internet] 2011 http://onlinemanuals.txdot.gov/txdotmanuals/acm/acm.pdf
3. U.S. Federal Highway Administration 2010 http://safety.fhwa.dot.gov/intersection/resources/fhwasa10002/