“…A safe, efficient, environmentally sound, and fiscally responsible highway transportation system is crucial to the nation's economy. However, the U.S. transportation system is confronting a series of challenges to sustainable development, including deteriorating physical conditions, delayed maintenance, increased traffic congestion, declining fuel tax revenues, and heavy reliance on fossil fuels (Bartle & Devan, 2006; W. R. Black, 2010;Leuenberger & Bartle, 2009;O'Connell & Yusuf, 2013;Wachs, 2003;Yusuf, O'Connell, & Abutabenjeh, 2011). These challenges have caused many people to become concerned with the future of America's transportation system (Kemp, 2005).…”