Below, the committee has assembled a list of opportunities for more efficient truck operations. This list is by no means exhaustive, but it is intended to provide a survey of the opportunities available. As noted above, this information may be useful to the DOE and DOT as they revise the white paper and identify the highest-priority areas for joint R&D. It is indicated whether each item is covered in the current draft of the white paper.
1. Vehicle maintenance. Tire pressure has been shown to have a measurable effect on fuel consumption (NRC, 2010). This factor can be addressed by frequent, scheduled maintenance checks or by automated tire-pressure-maintenance systems that are mounted on the vehicle. In addition, factors such as axle alignment have an effect on rolling resistance and thus on fuel consumption (NRC, 2010). Axle alignment can be checked and adjusted as needed as a part of routine maintenance. As the diesel particulate filter (DPF) fills with ash, regenerations become more frequent, costing additional fuel consumption. Proper maintenance of DPFs can limit fuel consumption. Several other maintenance factors can affect fuel consumption. Maintenance practices vary widely, so some operators may have little to gain from improved maintenance practices, whereas others might see a significant benefit. The DOT-DOE white paper addresses the topic of trailer maintenance, noting that research into parasitic losses could help determine whether some type of maintenance regulations aimed at reducing fuel consumption would be useful (DOE-DOT, 2011, p. 7).
2. Packaging optimization. Some goods are shipped in bulk or with minimal packaging, but many products have extensive packaging. In the case of many consumer products, the size of the package can be several times the size of the actual product. Because trucks carrying these types of loads are typically filled by volume before reaching their maximum weight, a change in packaging can allow a given truck to carry substantially more product. This means that fewer loads are required to deliver the same amount of product, directly reducing both the number of trucks in operation and fuel consumption. Some companies, such as Walmart and a range of consumer-product manufacturers, have put considerable effort into packaging optimization, but there is still scope for improvement. This topic is addressed briefly in the DOT-DOE white paper (DOE-DOT, 2011, p. 1).
3. Load management optimization. This term describes efforts by trucking companies to ensure that trucks run as close to full payload as possible over the shortest distance needed to make deliveries. “Deadheading” (running empty on the way to pick up a load) needs to be minimized. Sophisticated software is used by many fleets to optimize pickup and delivery routes, both in terms of distance and in terms of maximizing vehicle capacity utilization. Because trucking is a low-margin business, competition places intense pressure on trucking companies to improve their load management. The difference between profitable operation and bankruptcy can be a few percent difference in average load factor. Over time, more companies are implementing ever-more sophisticated load-management systems. However, it must be recognized that there are instances in which a truck needs to run empty or with a very small load, or else a given customer cannot be served at all. This topic is addressed in the draft white paper (DOE-DOT, 2011, p. 14).
4. Routing optimization. Routing determination is normally done using the same system used for load management. The goal here is to select the most time-and fuel-efficient route, which may not always be the shortest distance. Factors that are considered include congestion (which varies by time of day), speed limits, the number of traffic signals or other situations requiring stops, and hills. Planned routing can also be adapted in real time during operation to take into account special conditions such as weather or accidents. As with load management, this is an area in which the industry is investing a significant amount of effort, so there is little if any productive role for agencies to play. One exception may be in the area of providing realtime information on road conditions in order to allow continuous optimization of routes, perhaps by the use of vehicle-to-infrastructure (V2I) communications. Such communications for fuel economy purposes are mentioned in the white paper (DOE-DOT, 2011, pp. 7-8). Another area of opportunity for the agencies is to develop and maintain a database that includes information on road restrictions, road construction, hazardous materials routes, preferred truck routes, and so on, so that the route-planning software used by trucking companies has up-to-date data to work with. This idea is not mentioned in the DOE-DOT white paper.
5. Supply-chain optimization. It is not unusual for a product to contain many individual components that are shipped from all over the world to a final assembly point before the final product is shipped to the customer. For example, raw materials or specialized components may be shipped from the United States to China, combined with other parts from many countries, and then shipped back to the United States for sale. Manufacturers consider the cost of shipping when they set up a supply chain, but shipping is only one of many costs that are considered. If the cost of shipping increases significantly (for example, during a spike in fuel prices), then companies may reconsider their supply chains, especially if the increase in shipping cost appears to be permanent. When companies choose supply chains that involve extensive shipping,