“…The relay network design problem in freight transportation systems as studied in Ali et al (2002) is almost identical with RLP. The hub-and-spoke aspect of relay networks has originated with the work of Taha and Taylor (1994) and has been adopted as an alternative dispatching method for TL transportation in order to alleviate the common driver retention problem in several studies (please see Taylor et al (1999), Ali et al (2002), Uster and Maheshwari (2013), Uster and Kewcharoenwong (2011), Konak (2012), Vergara and Root (2013) and the references therein). Though relay networks and hub-and-spoke networks (not necessarily complete hub networks) are very similar, there are operational limitations such as circuity, distances between relay points, load balance at relay points, and number of handlings from origin to destination that are specific to TL transportation in relay networks.…”