Research

MeTrIS—Deadhead Reduction

The Problem
Figure 1. Bobtailing is the visible piece of the deadhead problem

This component of the MeTrIS project addresses the problem of “deadhead” travel by trucks in port cities, with particular reference to Los Angeles.

For each trip that hauls goods, there are on average 1.6 deadhead trips that reposition empty containers, chassis and tractors. Consider the steps:

  1. A full import container is hauled from the port to a warehouse in the Inland Empire—say Riverside.
  2. The empty container is brought back to the port. It may be re-exported as an empty, or there is (currently in LA) about a 50% chance that the empty container will be required by an exporter to ship goods overseas.
  3. If it is needed for export, it is carted to the exporter's warehouse.
  4. The full container is trucked back to the port for the ocean move.
Of these 4 container trips, only 2 move goods. In addition there are bare-chassis moves, and “bobtail” (tractor only) trips to pick up chassis and containers, all of which contribute to traffic congestion and emissions. Bobtail and chassis trips are commonly seen in port areas (Figure 1).

The Solution

Deadhead trips can be greatly reduced by establishing empty-container storage depots at strategic, optimized locations. The curves in Figure 2 show the reductions that can be realized under various scenarios.

The system-optimal model dictates to truckers where an empty container is to be taken, to optimize the overall system. In the user-optimal model, truckers serve their own interests by taking empties to the nearest depot. The sub-optimal models examine likely working scenarios where say only 80% of truckers are able to use the first-choice facility, while the remaining 20% use other facilities for various reasons. The curves in Figure 2 similarly document 50-50, 40-60 and 20-80 use of the first-choice facility.

With more depots, there is clearly a reduction in distance traveled, but it is the first 3-4 depots that have the greatest impact and are most worth the investment. With sub-optimal use, more depots are required.

The net benefit of these empty-container management strategies is an enormous reduction in empty movement (Figure 2), translating to approximately 25% reduction in port area VMT, and a reduction of 4,500 port entries and 50 tons of CO2 emissions per day.
Figure 2. A system of empty-container depots can result in dramatic decreases in travel


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