Practical Approximations to Quantify the Impact of Time Windows and Delivery Sizes on Freight VMT in Urban Areas

Supply chains and urban areas cannot thrive without the efficient movement of goods and accessibility to services. Commercial vehicle flows and VMT are the ultimate materialization of supply chain activities in the public road network (Figliozzi, 2006). From a freight planning perspective, it is crucial to understand and quantify how routes and distribution decisions translate into commercial VMT. A recent study indicates that commercial vehicles carrying goods or providing services account for, on average, almost 10 percent of total VMT in medium to large urban areas; a predominant share of trips that contribute to freight VMT originate at distribution centers…

Supply chains and urban areas cannot thrive without the efficient movement of goods and accessibility to services.  Commercial vehicle flows and VMT are the ultimate materialization of supply chain activities in the public road network (Figliozzi, 2006). From a freight planning perspective, it is crucial to understand and quantify how routes and distribution decisions translate into commercial VMT.

A recent study indicates that commercial vehicles carrying goods or providing services account for, on average, almost 10 percent of total VMT in medium to large urban areas; a predominant share of trips that contribute to freight VMT originate at distribution centers (DC) or warehouses (Outwater et al., 2005).  In urban areas, most of the trips take place within a multi-stop tour or trip chain. For example, in Denver multi-stop tours or trip chains, i.e. more than one stop per tour, account for over 90% of the total number of tours (Holguin-Veras and Patil, 2005)

In the logistics and operations research literature, modeling efforts have focused on the design of routes but not on the estimation of distances traveled or VMT. Nor have freight planning models been develop to quantify the impact of delivery size and time windows in urban areas. There is scant research relating number of stops per tour, delivery sizes, time windows, and VMT per tour. Delivery sizes and time windows have a significant impact on the efficiency and VMT generated by freight movements in urban areas (Figliozzi, 2007a).

The fundamental research questions of this proposal are:  a) how to obtain practical and intuitive approximations on the length of commercial vehicle tours and VMT travelled in urban areas? and b) is it possible to estimate the impact of time windows and delivery sizes on VMTs?