Because of the growing importance of hub-and-spoke operations in the
trucking industry, crossdocking has become an important and effective
tool to transfer freight. Companies like Wal-Mart, Costco and Home Depot
are using this kind of facility in their logistics operations.
Efficiently operating crossdocks, thereby reducing unnecessary waiting
and staging congestion for freight and workers are important issues for
managers.
To deal with the above issues, this dissertation uses real-time
information about the contents of inbound and outbound pallets and the
locations of pallets to schedule unloading for waiting trailers and
assign destinations for pallets. We show how to incorporate the
information of waiting freight in trailers to benefit trailer
scheduling; we also present how to use the information on freight
staging to mitigate congestion. Two dynamic trailer scheduling and four
alternate destination strategies are proposed accordingly and compared
with baseline scenarios in this research.
Our simulation results suggest that:
1. Our strategies are effective. The two time-based trailer scheduling
algorithms can save cycle times as high as 64%, 57% and 30% in the
4-to-4, 4-to-8 and 8-to-8 crossdock scenarios, respectively; the four
alternate destination strategies can save cycle times as high as 34% in
the 8-to-8 staging crossdock scenarios. In addition, these strategies
can raise throughputs for crossdocks. These effects should result in a
noticeable influence on supply chain networks, including shorter
transportation lead-time, more reliable on-time deliveries and less
inventory costs.
2. In our alternate destination strategies, even if a destination change
results in extra time for value-added services for freight, the
strategies are still worthy to adopt.
3. The combination models of our trailer scheduling algorithms and
alternate destination strategies work better than solely implementing an
alternate destination strategy when trailer arrivals are dense.
4. A higher flexibility on choosing alternate destinations can bring
higher performance for crossdocks.
