Tour Behavior of Clean Drayage Trucks in Southern California

In recent years a Clean Trucks Program (CTP) has been enacted at California's San Pedro Bay Ports (SPBP) of Long Beach and Los Angeles, to help address major environmental issues associated with port operations. "Clean trucks" (meeting 2007 model year emission standards) that utilized public funds to replace older, polluting drayage trucks were required to be fitted with GPS units for compliance monitoring. In late 2010, 94% of cargo moves at SPBP were reportedly made by clean trucks. The study reported in this paper is based on a year of such GPS data for a sample that in December, 2010 comprised 545 clean drayage trucks. Drayage trucks carry port cargo (mostly containers) to and from the ports and intermodal rail and transloading facilities (drayage trucks have at least one trip end on port or intermodal rail facility property). An analytical framework is introduced for processing the GPS data from these trucks to both interpret the trip chaining or tour behavior of clean drayage trucks, and to prepare sufficient tour data for clean truck modeling at the SPBP. It is found that SPBP clean trucks make an average of 3.1-3.9 stops per tour, depending on the open or closed nature of the tour, fuel type and monthly cargo type. Furthermore, newer diesel trucks tend to travel further and longer than liquefied natural gas (LNG) trucks, and monthly cargo volume changes have an effect on clean truck tour behaviors. An important finding is that clean trucks at the SPBP rely on daily-based operations and one day of travel behavior is not necessarily representative of any other day. These insights into clean truck behavior at the SPBP potentially provide more accurate depictions of current conditions and better projections of future conditions for freight related improvement plans and models.