Enhancing Freight Productivity
As the nation struggles to move freight demanded by businesses and consumers in an expanding economy and population, options that would improve performance of individual modes are sometimes neglected. Major opportunities exist, however, to increase throughput within the constraints of the existing system. A variety of productivity-enhancing opportunities exist for trucking and ports and waterways.
Trucking accounts for the largest modal share of domestic and export-bound freight movement: trucks move 62 percent of the value of freight in the United States and 29 percent of freight ton-miles. Among the major controls that the federal government continues to exercise over motor carriers are the limitations placed on truck and bus dimensions and on axle and gross vehicle weights for operations on Interstate highways. These limits originated from policies designed to ensure that pavements and bridges would not be overstressed and that vehicles could operate within design constraints, such as lane width and ramp curvature.
Initially, these limits were imposed only by the states, the first being introduced as early as 1913. Much later, Congress imposed a series of limitations, beginning in 1956 with maximum axle and gross vehicle weights for vehicles operating on Interstates. Recognizing that inconsistencies in state regulations regarding other vehicle dimensions were impeding interstate commerce, Congress subsequently placed uniform maximum limits on such dimensions for vehicles operating on Interstates, which are still in place today. Over the years, the intent of these regulations has expanded from protecting infrastructure to limiting competition for bulk freight between large truck operators and railroads and responding to concerns about the risks of mixing increasingly large trucks with passenger vehicle traffic.
Much of the domestic movement of goods moves by water (about 10 percent of ton-miles). The vast majority—about three-quarters—of international trade tonnage arrives and departs by water. Parts of this system are underutilized and others could be used more effectively. Opportunities to enhance trucking productivity are discussed next.