LIST OF TABLES
1. Growth of Commercial Trucks in Service, 1987-97 3
2. U.S. Census Bureau Comprehensive Category Lists for Truck Contents 10
3. Freight Movements by Trip Category in the Puget Sound Region 56
4. Freight Movements by Trip Category in San Francisco Bay Area 57
Regional transportation plans in the United States are required, by federal law, to cover the transportation of freight as well as the transportation of people. In reviewing examples of such plans, we found that freight transport in trucks -- the way most freight moves in an urban area -- is not usually described comprehensively at even a gross level of detail. Basic metrics, such as the fraction of trucks in daily traffic streams and simple descriptions of where and how familiar trucks, like those in the fleets of FedEx and Safeway, move during the day, are not available. The proportion of blocking accidents on major highways that can be attributed to trucks is not measured and reported, nor are the results of monitoring air pollution from the diesel engines that characterize large trucks. Furthermore, all the significant impediments to freight mobility are seldom acknowledged. Specifying these and other elements in a simple yet comprehensive description of urban trucking would foster a more constructive dialog among interested parties:
Government transportation leaders who decide on infrastructure investments
Shippers and truckers who are directly concerned with performance levels of freight movement
The general public, who perceive trucks more as an environmental impact than as support for economic sustenance and the quality of life in their community
We took on the task of designing a comprehensive description, which we call the Regional Freight Logistics Profile (RFLP). Our focus is intraurban trucking, the bulk of truck movement in an urban area. We reviewed literature describing the characteristics and policy issues bearing on freight and designed a series of quantitative measurements that provide a linkage between the characteristics of local delivery trucking and the public policy issues that stem from and influence these characteristics.
We found the design work challenging because of our intent to balance coverage of the variety of public and business concerns relative to freight against the costs and other practicalities of collecting data. Because the RFLP is data intensive, we recommend a concept of iterative incrementalism -- expanding over time in successive annual cycles beyond a necessarily limited breadth and depth of geographic and topical coverage at the initial implementation. A major feature is building expansion potential into the RFLP to anticipate and accommodate the data streams potentially available in the next few years from private telematics and Intelligent Transportation Systems (ITS) equipment installed on fleet trucks.
We reached the conclusion that priority action by government to relieve the increased travel times and lack of reliability in hitting delivery windows can be guided by measuring truck volumes and congestion levels on key road segments. We found reluctance on the part of private companies to reveal performance information, so we have designed an institutional approach to gathering truck fleet performance data that does not compromise confidential performance data from competing carriers and shippers. Metropolitan planning organizations (MPOs) should review the RFLP and decide if devoting resources to using it would contribute to a better understanding of urban freight. State and federal freight mobility offices with responsibility for technical assistance to MPOs would also benefit from examining the RFLP for potential adaptation and adoption.
The vast majority of daily traffic volume on the roads of any North American metropolis comprises vehicles with the primary purpose of transporting people from one place to another: cars, vans, SUVs, personal pickup trucks, and buses, all providing personal mobility.
In addition to the many vehicles that are moving people, other vehicles -- trucks -- are on the road to move things. In commercial service, trucks are becoming relatively more important in America's vehicle mix. See Growth of Commercial Trucks in Service, 1987-97 shows the number of U.S. trucks in several major categories of use over the 10-year period 1987 to 1997. The growth rate in the number of trucks has exceeded the growth rate in both population and number of cars, in each case by a multiple of two or more.See The fast-growing category called "services" includes all the common carrier and contract trucking companies that carry freight for customers in shipment sizes ranging from full truck loads (TL) and less-than-truck loads (LTL) to express packages and overnight letters. This category also includes the commercial trucks that carry repair and maintenance personnel with tools, replacement equipment, and parts. Common carrier and contracted trucks serve all sectors of the economy, so trucks classified under "services" is not an accurate measure of the trucking needs of the services sector of the economy, as opposed to manufacturing or resource extraction.
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Source: U.S. Bureau of the Census; Federal Highway Administration |
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However, truck traffic is still a small fraction of total traffic in most circumstances. Trucks moving freight typically represent between 5 and 10 percent of vehicles over the course of a day in a U.S. metropolitan region. In the San Francisco Bay Area, trucks are reported to represent 5.5 percent of traffic (Bole 1997). In the central Puget Sound region, heavy and medium trucks generated approximately 6.2 percent of the vehicle hours in 1998 (Outwater 2001). The percentage is smaller during peak commuting hours and larger during off-peak periods, especially late at night when most people are asleep and the roads are more reliably clear of congestion.
Compared to railroads, trucks are dominant. In California, trucking dominates shipments more than in the rest of the nation, capturing over 60 percent in ton-miles of California's shipments, compared to less than 40 percent for the nation as a whole. Trucks also capture the higher-value shipments, such as electronics. In California, trucks carry more than 67 percent of the value of all shipments (Deakin, et al. 2001).
Truck movements support the economic vitality of a region. Freight -- including goods, cargo, packages, construction materials, bulk commodities, and outgoing waste material -- encompasses the things that factories, offices, warehouses, stores, and households make or in some way prepare for shipment elsewhere. Freight also encompasses the things that factories, offices, warehouses, stores, and households need to receive and use. Because cities grow in parallel with an ongoing increase in the specialization of labor, many needed things are produced elsewhere. Human life in advanced economies depends on the food, clothing, construction materials to build shelter, fuel, medical supplies, tools, and other essentials that move as freight. Economic prosperity, our way of life, and many of the pleasures of living beyond the bare essentials are also supported by freight movement. Human survival, sustainability, and progress as most people understand these concepts require that freight transportation exist and work well.
Federal law requires U.S. regional transportation planning organizations to focus on the movement of freight as well as people. In response to that mandate, regional transportation planning for freight in the United States has put most of its emphasis on increasing the efficiency of intermodal freight in support of trade between regions, that is, the regional contribution to the movement of goods between cities, nations, and continents. The central contribution of long-haul shipping to trade and economic prosperity and the availability of data on interstate and international commerce are the cause of this focus. For urban planning, this emphasis means examining and improving how freight moves into and out of urban areas and between modes within an urban area as part of a long-distance journey. This leads to the visible emphasis on freight movement across the northern and southern boundaries of the continental United States and into and out of marine ports.
As the economy becomes more global, products increasingly move between nations and continents, as well as between cities within the nation. All modes of transport are involved. Ships and barges, railroads, trucks, pipelines, and airplanes are important means of freight movement. Focusing on trade-related freight leads one to study the movement of freight in and out of marine docks, airports, and rail yards, as well as the passage of large trucks along the interstate highways connecting cities. A map of the United States illustrating the flow of freight movements by truck between metropolitan areas is shown in . The thickest lines, of course, follow the Interstate Highway System.See A series of state maps illustrating freight flows is available in a comprehensive national data and analysis tool (the Freight Analysis Framework) from the Federal Highway Administration. State profiles are available for download at http://www.ops.fhwa.dot.gov/freight/state_profiles.htm
Nationwide Truck Freight Flows
Source: Ohio DOT at http://www.dot.state.oh.us/planning/Studies/Freight/freight_default.htm
Similar maps exist for railroad freight and for the portion of freight that moves through seaports for transport by ship. Less examined by transportation planners, typically, is the process of moving freight within the confines of urban areas. Here, trucks are dominant, with some exceptions. One exception is certain liquid and gaseous products--water, natural gas, sewage, some industrial wastes, and liquid petroleum products-- that move in pipes. Short-line railroads move some material within cities, and conveyer belts move some coal and gravel. When modes other than trucks are part of freight movement to destinations within a region, there usually are intermodal transfer points where freight is transferred to or from trucks.See Exceptions include facilities such as marine bulk terminals for grain and coal served by rail cars only; power plants receiving fuel strictly by railroad, barge, or pipeline; and rail-on-dock marine ports where containers move directly between ship and railroad. Examples where trucks are part of intermodal transfers include gasoline delivered to retail filling stations from pipeline terminals, air-express packages moved to and from airports, new automobiles delivered to car dealers from marine and rail terminals, and standard shipping containers moved to and from warehouses from both marine container ports and intermodal rail terminals.
An illustrative map of truck flows within one urban region of the United States, Seattle-Tacoma, is shown in See Puget Sound Regional Truck Volumes.
Puget Sound Regional Truck Volumes
Source: FASTRucks Study, Washington State Department of Transportation
The Mobility 2001 reportSee Massachusetts Institute of Technology and Charles River Associates Incorporated. Mobility 2001. Report prepared for Sustainable Mobility Working Group of the World Business Council for Sustainable Development, at http://www.wbcsdmobility.org. describes several specific benefits to an urban region that come from freight mobility:
Manufacturers and distributors obtain raw materials, parts, subassemblies, and complete products from distant sources.
Firms consolidate production and goods distribution services to achieve economies of scale and sell to a larger market.
Individuals obtain food, energy, construction materials, and other goods reliably at costs of time and money that do not discourage development and growth.
Producers and individuals send and receive packages and other shipments of different sizes without excessive cost or time.
Metropolitan areas grow larger because economies in freight delivery support scale and density in public services, production, housing, and other economic sectors.
Metropolitan areas can have lower density through easy transport of goods within the region.
These benefits are thought by those associated with the trucking industry to be under-appreciated in public deliberations about transportation investment. In Washington State, those professionals focused on maintaining freight mobility are fond of saying, "freight doesn't vote." A civic leader in Oakland, California lamented to a journalist, "I don't think anybody in the position of decision making or anybody in the position of power has spent any time thinking about how goods are moved. They think goods get to Kmart in a taxicab." See Levine, Daniel S. "Congestion also holds up goods, not just commuters," East Bay Business Times, July 15, 2002. Quote from Marianne Dreisbach, a director of the Industry and Labor Alliance.
This study is a reaction to the lack of public appreciation of freight issues.
Introduction to Urban Freight Movement
This project seeks to characterize freight in ways that support planning and policy improvements that maintain and improve intraurban freight movement. Our intent is to elucidate some key characteristics of urban freight movement, for example, growth in vehicle volumes, the expanding number and dispersion of urban origins and destinations, changes in vehicle size, variations in vehicle loading, and the requirements of timing for deliveries and pick up. We will show the design of a planning tool that displays the key characteristics of intraurban freight movement and thus points to public policy changes that reduce the social cost of urban freight movement.
Professor Kenneth W. Ogden of Australia has written a comprehensive book on urban freight, Urban Goods Movement: A Guide to Policy and Planning (Ogden, 1992). We will draw from, build upon, and extend Ogden's work to provide some initial structure to urban freight issues.
In this chapter, we first describe basic supply and demand factors in urban freight, then discuss logistics, identify the supply factors in freight movement, look at the interaction of supply and demand in truck movement, and end with a discussion of the scope of the proposed regional freight logistics profile.
Demand factors in freight movement
There are three demand factors in freight movement: what is moved; the places between which goods are moved; and business processes governing movement, including the timing of movement.
The first element of demand in freight movement is the type of goods that are moved, that is, what the trucks are carrying. We are interested in finding enough detail about the cargo moved within cities to understand what influences the movement of trucks.
Standard, comprehensive categories of what trucks carry are provided by the Census Bureau's Standard Transportation Commodity Classification code (STCC) from the Commodity Flow Survey and Principal Products Carried classification from the Truck Inventory and Use Survey (TIUS), as shown in See U.S. Census Bureau Comprehensive Category Lists for Truck Contents.
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Building Materials (sand, gravel, concrete, flat-glass, etc.) |
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Building Materials (sand, gravel, concrete, flat-glass, etc.) |
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Merging everyday experience with the comprehensive lists in the table above, a preliminary simplified categorization of the most significant types of freight found in intraurban transport follows:
Packages and mail for offices and households
Food and beverages for grocery stores, restaurants, and other meal service facilities
Appliances and furniture for households and offices, both deliveries of new furniture and moving of existing items
Automobiles and other motor vehicles
Other stock bound for retail stores and other walk-in supply and service facilities
Fuels, including gasoline, diesel fuel, and home heating oil
Other factory output (finished goods)
Factory input (raw materials, parts, subassemblies, and packaging materials)
Trash, refuse, garbage, recycling
Full and empty cargo containers moving between points of unloading/loading/intermodal movement, known as drayage
The Regional Freight Logistics Profile developed and described later in this report provides a place to indicate categories of freight as part of fleet descriptions.
The economy of metropolitan areas provides an increasing variety in the goods that consumers and businesses demand. While volume of food per household per day may not be changing much, the variety of food items is expanding. For example, the number of different items in an average grocery store grew from 10,000 in 1980 to more than 30,000 in the mid-1990s (McKenna, 1995).
While an office complex may require an ongoing volume of pens, pencils, paper, and other office supplies, the variety of pens, papers, and other office supplies demanded and used in offices has increased, and the rise of the office supply superstore has occurred. Because of the variety that the market can and does produce in parallel with demand, and the ability of computers and electronic data flows to keep track of a larger number of separate items, there are more kinds of distinctly different goods (each separate kind is known in retail as a different stock-keeping unit or SKU) that make up freight flows.
Ogden (1992) claims that the volume proportion of most categories within the total freight mix has not changed much over time as the economy and freight volumes have grown. However, a few specific categories, such as packages for express delivery, are increasing relative to the others.
The second element of demand is land use, meaning the homes, offices, stores, factories, and warehouses, both where goods originate and where they are delivered. Complicated business processes such as production systems and supply chains are embedded in land use, but we will seek simplifications as much as possible.
A preliminary categorization of land uses in a metropolitan area includes the following:
Housing units, including single-family and multiunit
Retail stores and service facilities, including restaurants, hotels, and hospitals
Office buildings, including government and schools
Factories and processing facilities, including laundries and printers
Wholesale distribution centers and other short-term warehouses where goods arrive and leave actively, including post offices
Long-term warehouses and storage facilities, where goods are stored for weeks or months
Truck depots (sometimes adjacent to warehouses) where trucks are stored and dispatched
Sports arenas, fairgrounds, convention centers, and other temporary exhibition venues
Refuse transfer stations, recycling centers, landfills, waste treatment plants
Intermodal terminals (airports, seaports, rail terminals, pipeline terminals)
This categorization is a starting point for the design of the RFLP later in this report.
See Typical Commercial Truck Trips by Land Use Destination illustrates how commercial trips are distributed across land uses in an unnamed metropolitan area that was studied. Home base refers to a distribution center, motor pool, or other garage from which trucks are dispatched each workday.
Typical Commercial Truck Trips by Land Use Destination
Source: Michael Meyer, http://www.fhwa.dot.gov/freightplanning/meyer.htm
According to Ogden, based on data from a decade ago, the proportion of trips that is generated by each different land use appears to be fairly stable. This generalization needs to be verified in the present day in regions of interest. He also noted that more suburban locations for the origins and destinations of freight resulted in truck trips increasing in length over time.
Another land use distribution issue is the growing volume of package delivery to private housing units as online shopping grows. This is the result of more online and mail-order catalog shopping by consumers, telecommuters working at home, and business owners.
A demand factor not delineated by Ogden is the effect of business processes, the methods by which businesses carry out their work. Business processes influence the timing, quantity, and packaging characteristics of freight movement, such as day of week, time of day, frequency of delivery, speed of delivery, and package sizes. For example, one restaurant may keep food delivered on Monday in refrigerated storage so that it is still fresh on Wednesday. Another restaurant may want fresh food delivered every day. One office may assign a person to help a delivery truck driver unload an arriving shipment. Another office may have no such person and may be situated in a building with a small elevator that allows only handcarts of a certain size, so that multiple trips in the elevator are required by the delivery driver.
Logistics
A general term for an important category of business process that impacts the demand for freight is logistics, defined overall as "the process of planning, implementing, and controlling the efficient flow and storage of raw materials, in-process inventory, finished goods, services, and related information from point of origin to point of consumption (including inbound, outbound, internal, and external movements) for the purpose of conforming to customer requirements." See Noted at http://www.fedex.com/us/services/logistics/faq.html. Supply chain management is a nearly synonymous term. Transportation management is the subcategory of activity within logistics and supply chain management that is of interest in this study.
Traditionally, logistics is inventory-based, following a "push" model, in which factories or distribution centers push goods out to fill inventories further downstream toward customers. If factories are fast and flexible, and if communications and transportation can operate faster and in coordination, the model can shift gradually to one in which customers order what they want directly from factories and distribution centers. Goods are then made specifically on demand, or "pulled" from stock, to fulfill customer orders and shipped directly to them. Rather than having goods pushed on them by overstocked stores and supply systems holding sales and offering bargains, retail customers pull what they want for replenishment of their needs when they want.
According to a study commissioned by FHWASee Reebie Associates, Inc. "Business Logistics: From Push to Pull Logistics," 2001. Working paper for the Federal Highway Administration Office of Freight Management and Operations, available at http://www.ops.fhwa.dot.gov/freight/adfrmwrk/index.htm. "inventory-based logistics prototypes still dominate among most large-scale manufacturing and distribution firms. Inventory-based logistics also represents the primary model for `E-tailing' (Internet-based retailing): national or regional warehouses supplying home and business delivery with airfreight and package delivery services." The FHWA study continues: "The manufacturers and retailers we interviewed believed that replenishment-based logistics systems offered efficiency versus traditional inventory-based models, but were reluctant to risk the increased stockouts perceived to accompany replenishment models. We found little evidence of pure pull systems in high-volume logistics applications. The companies interviewed did not anticipate a major shift over the next decade, but rather a gradual expansion of pull systems in response to increasing pressure to improve customer service and still reduce inventories."
Note that a single supply chain of goods can encompass both push and pull elements. In other words, a large central warehouse in a metropolitan area may pull inventory for the retail store chain it serves in a replenishment mode of operation, then push the inventory it acquires out to the stores as rapidly as possible. The opposite configuration also can exist. Various manufacturers could push inventory to a wholesale company with a large warehouse, but the warehouse serves a variety of stores with rapid delivery of what the store managers order and pull out. This is analogous to the differences between household members who buy groceries as needed on the way home and those that have large storage cabinets of food bought in response to the availability of bargains at grocery stores.
Logistics is a business process that evolves over time under the influence of many nontransportation factors but also is influenced by transportation public policies that impact the access to each physical location of the firm. Such public policy influences the availability and quality of road infrastructure, the cost of shipping as impacted by the level of road-related taxation, and the timeliness of deliveries influenced by the level of road congestion.
Many reviews of the transportation implications of logistics describe the following features that influence the movement of freight in the gradual evolution from push to pull logistics.
Centralized warehousing : Businesses are finding that they improve efficiency by reducing the number of warehouses for storing and distributing products. This lowers the inventory levels but also increases the lengths of delivery trips leaving from warehouses (Cambridge Systematics 1995).
Warehouses have become more active as sorting and distribution centers, with trucks coming and going with more frequency. Large multiacre locations where goods can be moved from dock to dock quickly and trucks can get in and out without facing frequent congestion become a much-sought resource. Such facilities are more compatible with low-density suburban areas than with high-density central cities.
Crossdocking: A growing trend in warehousing is crossdocking, a flow of freight through a warehouse characterized by goods arriving on one loading dock by truck, quickly sorted, and within hours directed to another dock where a second truck waits to take them away.
Warehouses on wheels : The flow of goods from factories to point of consumption can be managed tightly by telecom and computers, to the point that inventories can be managed even while in motion aboard airplanes and trucks.
Harry Caldwell, chief of the Freight Policy Team at Federal Highway Administration, says, "Using the transportation system as a form of rolling warehouse allows the private sector to reallocate its resources away from warehouse maintenance and leasing to basic and applied R&D, equipment development, and worker training and retraining. . . . But as levels of congestion increase on our nation's transportation system, higher levels of unreliability and unpredictability are created, and that causes true problems for U.S. companies that have to rely on the system as a dependable asset." See Quoted in Public Roads Magazine, March/April 2001, "Giving Freight a Voice" by S. Lawrence Paulson.
Just in time : In manufacturing, more delivery activity and smaller inventories is called just-in-time (JIT) supply. In retailing, this pattern is called quick response.
As reported by Cambridge Systematics in its 1995 review for the NCHRP, "JIT systems focus on keeping inventories at minimum levels through a coordination of input deliveries with production schedules. Adopting a JIT system usually results in increasing the frequency with which inbound shipments are scheduled, decreasing the lead times for these shipments and their size, and increasing the importance of receiving these shipments on time. Firms adopting JIT systems frequently reduce the number of suppliers and transport companies with which they deal, and they require suppliers that are close enough to be able to deliver shipments reliably within the constraints of short lead times."
In retail quick response (QR), the stock in a store is minimized. Replenishment of stock may be triggered by the supplier keeping track of sales of each item. Express package delivery is used by some retailers to obtain needed items.
The effect of JIT and QR in reducing the relative importance of inventory cost in logistics is seen in the shrinking share of GDP the inventory costs represent in the U.S. economy. This is shown in See Logistics Expenditures in Relationship to Gross Domestic Product where the blue line has dropped lower since the early 1980s.
Logistics Expenditures in Relationship to Gross Domestic Product
Source: Prologia and Cass Information, Inc., 12th Annual State of Logistics Report , June 4, 2001.
Customer use of service options : The package delivery industry -- including Federal Express, Airborne Express, the U.S. Postal Service, and United Parcel Service -- now offers several grades of guaranteed delivery speed. Service grades include first day morning, first day afternoon, second day, and three day, a gradation that leads to more and more truck delivery runs by these competitors throughout the business day and even on weekends.
The emphasis on fast, guaranteed delivery times leads to the dispatch of more trucks carrying only partial loads, instead of waiting for enough cargo to fill a truck up. When common carriers are involved, Internet applications have been designed to facilitate the creation of transportation capacity brokerages that buy and sell available capacity on trucks that would otherwise move out with only partial loads.
Electronic commerce : The use of electronic messages in maintaining relationships and fulfilling transactions is increasingly a feature of logistics and other business processes. E-commerce is a growing feature of consumer relationships with business, but is even more a feature of business-to-business transactions. The World Wide Web and electronic mail make out-of-town sources of supply more visible and accessible to customers in homes, businesses, and institutions of all kinds. More online and telephone ordering by households and businesses feeds and facilitates the growth in package shipments over long distances, reducing intermediate local stockpiles of goods (Browne, 2001).
Supply factors in freight movement
Returning to Ogden's analysis, we can identify three supply factors in freight movement: road networks, truck characteristics, and nonroad networks. We reclassify Ogden's "truck movement" supply factor as the result of interacting demand and supply factors.
The first supply factor, the road network over which freight travels, makes up the paths that freight follows as it moves. As with passenger vehicles, truckers gravitate wherever possible to the use of limited-access highways and arterials, in order to move faster. Because deliveries by truck are made at least occasionally to every developed location, urban freight travels on almost all roads at least some of the time. Exceptions can be found. Some metropolitan areas have parkways with truck restrictions because of lane width or height impediments. Many locations have particular road segments where certain types of trucks are banned by regulation because of noise, height, width, length, weight, or type of cargo. Limitations of bridges and tunnels are a common cause of restriction. Some regions and jurisdictions designate a subset of major roads and highways as truck routes for which special accommodations may have been made, such as traffic-light timing that recognizes the acceleration and braking characteristics of heavy trucks.
The second supply factor is the trucks themselves. Our emphasis in this report is on trucks used commercially for moving goods, not the growing volume of smaller trucks used primarily for personal travel with the cargo area used for personal belongings. Personal travel, the bulk of urban movement, is already covered by MPOs with existing modeling and planning tools. Therefore, trucks used for personal travel, including the movement of employees on business such as repair or inspection, are outside our scope. This exclusion also encompasses trucks, vans, and SUVs that individuals use to bring home goods such as groceries, furniture, or construction supplies for their own household consumption.
The modern economy and its resulting lifestyles have produced a set of new consumer services directed at the home that did not exist previously in their present scope and volume. A house is becoming technically more complex, and the busy working people who live in houses cannot always maintain the features and systems themselves. Such services include home security; telephone, cable TV, and satellite antenna installation; landscape services; housecleaning; food delivery; used goods pickup; and package delivery. Businesses rely on services that are even more extensive and specialized, including equipment maintenance services. Although service delivery is an important component of traffic volumes, our focus here is on the services that incorporate the movement of material (including waste) that requires the use of trucks that are larger than cars and thus are distinctly truck-like.
Therefore, a Sears appliance repair van is not within our scope, but a Sears truck delivering and installing an appliance is within it. A post office or FedEx delivery truck or van is of interest here, but the van of a plumber or electrician is not. Within any category of delivered goods, we will classify the vehicle in or out of our scope based on the dominant vehicle type. For example, most pizzas are delivered in cars; therefore, we will not focus on the relatively small number of pizza delivery trucks that flow in a city. Landscape and tree service trucks would be counted in our scope of concern because of the vehicles' size.
In general, we consider trucks with more than two axles or more than four tires to be carrying freight, whereas many (but not all) smaller trucks are for personal or business-related human mobility. We exclude rental trucks of any size employed by individuals for short-term moving but include leased trucks of any size used by stores and other businesses for deliveries.
Because there are gray areas between car use and truck use in service delivery that also includes goods, the final determination of what counts in or out of the RFLP is a subject for future refinement.
Classification by Size
The Quick Response Freight Manual (Cambridge Systematics 1996) provides the following basic, three-way classification of trucks by size:
Light Trucks: Four-tire commercial vehicles, including delivery and service vehicles. Pickups and vans fall into this category.
Medium Trucks: Single-unit trucks with six or more tires.
Heavy Trucks: Combination trucks consisting of a power unit (truck or tractor) and one or more trailing units.
Ogden (1995) reports a growing preponderance of heavier (larger) trucks in urban freight movement, although other fragmentary evidence (U.S. DOT 1995) suggests the opposite. There is logic on both sides.
A rising proportion of smaller trucks would be suggested by just-in-time logistics delivering smaller quantities more often and the need for vehicle maneuverability in growing traffic congestion. Larger trucks are suggested by driver shortages, the goal of increasing driver productivity through economies of larger vehicles, the goal of improving energy efficiency, the influence of third-party logistics services with multiple clients, and the growth of high-volume, lightweight packaging techniques. Actual measurement proposed later will show which trends predominate.
On the last point, a technological trend in packaging is the increasing use of high-volume, lightweight plastics such as styrofoam and bubble wrap (Cambridge Systematics 1995). Reportedly, this has caused shipments of manufactured goods to have a lower average density and thus to require bigger trucks to carry the same weight of products.
Classification by Shipment Size and Truck Ownership
Truck owners include individuals and organizations. Owners of trucks who carry freight for a fee fall into four segments: truckload (TL), less-than-truckload (LTL), package express, and logistics (National Research Council, 1999).
TL carriers move shipments weighing over 10,000 pounds and averaging 27,000 pounds from one location to another, with each load occupying the cargo area exclusively.
LTL carriers move shipments weighing between 150 and 10,000 pounds, with multiple shipments occupying the cargo space. They try to consolidate loads and coordinate deliveries.
Package express refers to carriers like FedEx and UPS who move shipments weighing less than 150 pounds, often in conjunction with overnight air shipment between cities.
Logistics, or "third-party logistics" (3PL), is a new category of firms that appeared in the past decade. 3PLs provide a comprehensive suite of freight-moving services, using different vehicle sizes and modes as needed to provide the most efficient service. The previous three categories of firms are increasingly offering logistics services. For example, package express carrier UPS provides logistics service to Ford Motor Company and is responsible for moving all its new cars from the factory to the showrooms (Mitchell 2001, pp. 21-28).
In addition to firms that carry freight for a fee as a business, there are private carriers that are part of the operations of a firm that generates a freight movement requirement. Firms such as Frito-Lay, Safeway, and Boeing own the trucks that carry the firm's goods as part of a business process that includes distribution of product to customers and transfer of goods between the firm's different locations. According to the trade association National Private Truck Council (NPTC), corporate or "private" truck fleets are operated by manufacturers, distributors, processors, and retailers to meet their inbound and outbound transportation needs. Such fleets include food, retail, wholesale, construction, and service companies. NPTC reports that the two million vehicles in the private motor carrier fleets account for approximately 82 percent of the medium- and heavy-duty trucks registered in the United States and generate approximately 53 percent of all the U.S. miles traveled for medium- and heavy-duty trucks. In other words, private fleets make up the largest segment of the trucking industry.See National Private Truck Council website at http://www.nptc.org/index.html
A third distinct supply factor in the analysis of freight is the nonroad transport network, meaning infrastructure and associated vehicles for transporting goods on nontruck modes, such as the pipelines, railroads, shipping lanes, and airways between cities. From the urban freight point of view, the main interest in the nonroad modes and networks lies in the necessarily limited number of intermodal terminals providing the points of freight transfer between the nonroad modes and trucks. Such terminals are marine ports, airports, intermodal railroad yards, and access points to pipelines.
Interaction of Supply and Demand: Truck Movement
The ease of trucks' movement over the road network is the freight issue of most interest for regional transportation planning organizations and the citizens and businesses that reside in a region. Therefore, we are interested in characterizing the efficiency of truck movement for planning and policy purposes.
Most freight traffic in the United States is local and regional, as opposed to interstate and intercity. As reported in the Quick Response Manual, See Cambridge Systematics. Quick Response Freight Manual, Federal Highway Administration, 1996. the coding for "range of operation" in the Bureau of Census' Truck Inventory and Use Survey reveals that "about 36 percent of the vehicle miles traveled by trucks occur on trips of less than 50 miles, and an additional 30 percent fall into the category of 50 to 200 miles. Moreover, 95 percent of all trips are less than 200 miles in length, with 81 percent less than 50 miles. Thus, the majority of all truck trips are local, and most vehicle miles can be considered local."
As noted earlier, the best data exist for intercity trucking because of data collection supporting interstate commerce regulations and truck weight monitoring. The trend of growing freight movement generally is indicated by the measurement of ton-miles of freight per capita moving in intercity trucks, as shown in See U.S. Intercity Truck Freight Volumes.
U.S. Intercity Truck Freight Volumes
Intercity truck freight, as illustrated above, is around 10 tons per capita, with a growth trend as of 1990. The magnitude of intracity freight in the 1990s was larger, estimated as 21 tons per capita in 1993 and 24 tons in 1997, using the Commodity Flow Survey data of the Census Bureau for shipments less than 50 miles on all modes, which for this short distance overwhelmingly means trucks.
Urban trucks tend to move during the normal business day with an hourly pattern that indicates an attempt by commercial firms to avoid peak commuting hours. An example of a pattern detected by Michael Meyer in an unnamed region is shown in See Typical Truck Trip Distribution by Time of Day.
Typical Truck Trip Distribution by Time of Day
Source: Michael Meyer at http://www.fhwa.dot.gov/freightplanning/meyer.htm
Truck traffic in a metropolitan region can be logically divided into four categories:
Through trucks : Trucks entering and leaving the region within a few hours or so (transitting), without a transaction related to the cargo. (However, there may be a stop for driver rest/relief or vehicle fueling.) For example, a truck traveling from Vancouver, Washington, to Vancouver, British Columbia, along interstate highways.
Interregion shuttle traffic: Trucks that travel between a single destination in the region and points exterior to the region. For example, picking up containers at the Port of Seattle and taking them to Wenatchee or truck traffic in the opposite direction.
Intraregion shuttle traffic : Trucks that travel back and forth between two major facilities, such as intermodal facilities and distribution centers. For example, picking up containers at the Port of Tacoma and shuttling them to distribution centers located in Kent, a city north of Tacoma with many such facilities. Shuttle traffic is also called drayage.
Generally in-region, multiple-stop, urban pick-up/delivery : This pattern represents what can be called urban delivery tours, of which there is a main case where trucks remain within the region of interest and four variations where trucks work outside the region as well as within.
Urban delivery tours, main case: Trucks that begin every workday at an in-region fleet depot, office, or driver's home, conduct multiple transactions within the region, then return to the starting point at the end of the work period, typically one day.
Urban delivery tours, variation one: Some of the stops may be outside the region, although the daily tour returns back to the starting point in the region. For example, a UPS fleet in a metropolitan area that provides some delivery services beyond the boundaries of the metro area.
Urban delivery tours, variation two: Trucks enter the region and travel to multiple transactions, and then leave the region. Trucks in such a pattern could be based at nearby depots outside the region or might arrive sporadically from far away. For example, a truck from Wenatchee, Washington, an agricultural center, delivers fruit to multiple warehouses, then returns to Wenatchee.
Urban delivery tours, variation three: Trucks that begin the work cycle in the region, conduct transactions at one or more regional locations, then leave the region to return one or more days later. For example, a common carrier truck starts from a depot, picks up freight at three locations around Seattle-Tacoma, then proceeds to Portland, Oregon.
Urban delivery tours, variation four: Trucks that enter the region near the end of a work cycle, conduct one or more transactions, then are parked for a period before beginning the next work cycle, which will involve more in-region transactions, then leaves the region. For example, a common carrier truck arrives from Spokane, delivers its cargo to four locations, then parks at its owner's depot in Seattle, awaiting the next assignment.
Ogden reports that the distance traveled by truck in a day has increased along with truck trip length, but he notes that total daily trips per truck do not appear to have changed much. This indicates that the distance between stops on a daily tour has become longer.
Each particular type of truck cargo has a distinct and often multitrip movement pattern within the urban area. The combination of goods and land use generates the freight that needs to be transported, with variation between goods and firms transporting goods that result in a variety of movement patterns. For example, gasoline may enter an urban area via a pipeline and be transported by tanker trucks between pipeline terminals and retail filling stations. Heating oil is transported between storage depots and homes. Groceries, clothing, and hardware may arrive from outside the region to a distribution warehouse, then be transported to retail outlets. Construction materials are transported between supply yards and building sites. Trash trucks pick up at homes and take their contents to transfer stations. Larger trucks move trash between transfer stations and a landfill, incinerator, or a railroad yard. When trucks lack a back load of returned merchandise or some other cargo, they travel empty.
More generally, truck movements can be characterized by origins and destinations that fall across land use types, as described earlier. The land use types also have a relationship with sectors of an urban economy. A representation of these sectors, with an indication of the geographic positioning of the sectors vis-a-vis an urban region, are shown in See Types of Freight Movement by Trucks in an Urban Region. Each symbol represents a land use type and corresponding freight origin and destination type within a region, except for the symbol at the upper left, which represents freight origins/destinations outside the region of interest. The regional land use types represented are factories; warehouses/distribution centers; retail and service locations; residential (homes); and intermodal terminals.
Factories (F): Includes the major institutions of the manufacturing sector, including materials processing and food processing. The distinguishing characteristic is a high volume of inbound and outbound goods that are distinctly different.
Warehouses (W): Includes warehouses, distribution centers, package and mail sorting centers, break bulk facilities where goods inside shipping containers are removed, and the like. The distinguishing characteristic is a high volume of inbound and outbound goods that are largely the same goods, although the packaging and load sizes may differ.
Retail and Service (R): Includes stores, professional supply houses, restaurants, hotels, commercial and government offices, medical and educational facilities, and other facilities where individual customers go to purchase goods or where goods are consumed by workers. The distinguishing characteristic is a large supply of inbound goods that are purchased and taken away by customers in personal vehicles or used on the premises. A further breakdown of this category may emerge later in the study. Currently, sports arenas and exhibition centers are included in this category.
Residential homes (H): All houses and housing units are in this category.
Intermodal terminals (I): Places where truck cargo is loaded for shipment on other modes of transportation, such as railroad cars, marine ports, and airports.
The arrows in See Types of Freight Movement by Trucks in an Urban Region represent freight flows between land use types by truck. Thicker arrow lines represent higher-volume flows. The arrowheads indicate the predominant directions of flow, although the flow is bidirectional in all cases. We can identify 11 different freight flows, as depicted in the diagram.
Types of Freight Movement by Trucks in an Urban Region
External--Factories (E--F): Raw materials, parts, and subassemblies flow from sources external to the region direct to factories. The output of factories, including processed materials, parts, subassemblies, and finished goods, flows from factories to destinations outside the region.
External--Intermodal (E--I): Since intermodal terminals such as seaports and airports typically serve a larger area than the immediate urban region, trucks flow to and from the terminals from outside the region.
External--Warehouses (E--W): In many circumstances, distribution centers send or receive goods beyond the urban region in which they are situated.
External--Retail & Service (E--R): Retail stores and offices may have deliveries from trucks coming in from external to the region, for example, if a wholesaler is located in a different city.
Factories--Intermodal (F--I): Some factories ship their output, or receive their input, directly by truck via an airport, seaport, or railhead.
Factories--Warehouses (F--W): Most factories receive some or all of their raw materials, parts, or subassemblies from local warehouses and/or ship to local warehouses, in addition to receiving or making shipments external to the region.
Factories--Retail & Service (F--R): Some factories ship directly to retail and service locations within the region, for example, bakeries and fish processors shipping directly to grocery stores in some regions.
Warehouses--Intermodal (W--I): Some warehouses pack standard containers for shipment, which are then trucked to railheads and marine terminals in the region.
Warehouses--Retail & Service (W--R): Wholesale warehouses shipping to retail outlets are a major category of urban freight. Office supplies and packages arrive at office complexes from warehouses and sorting facilities.
Warehouses--Homes (W--H): Mail and overnight packages arriving at residential locations originate from warehouses and sorting centers.
Retail & Service--Homes (R--H): Appliance stores and pizza shops are examples of businesses that move goods direct to residential locations.
Not shown, but implicit in the diagram, are flows from one location in a category to a different location in the same category. For example, output goods at one factory can be loaded up and taken to another factory (F--F), or there can be a shipment of retail goods from one central warehouse to a distribution center at another location (W--W).
Shipping containers can flow from seaport to railhead (I--I). A library or bookstore or company with multiple locations can ship books or other materials from one branch to another (R--R); a moving company can move furniture between two end-user locations (H--H) or (R--R).
Materials for building construction can fit into any of these patterns. Refuse removal fits into the scheme with some reverse flows if landfills and incinerators are considered to be factories.
Sports arenas, conventions centers, hotels, and motels can be considered a special case of retail venue.
Scope of the Regional Freight Logistics Profile
Our intent in the design of the RFLP is to create a tool that makes urban freight comprehensible to public sector transportation planners and policy makers. We want the RFLP to provide an overview of how truck traffic interacts with the more prevalent passenger traffic in cars and other personal vehicles. We want it to show MPOs how to measure and monitor trucks interacting with congestion -- avoiding it, dealing with it, and causing it. To be useful, the RFLP must also provide some focus and direction on solving problems that are identified.
The RFLP will identify and account separately for trucks that are passing through the region as opposed to those that are conducting business by making stops for loading or unloading within the region. Those making stops can be divided into interurban and intraurban truck movements. Because of the relatively high number of intraurban truck trips compared to interurban, we will focus on the intraurban and treat the other types as context. Examples of the kind of trucks in which we are most interested are package services such as FedEx and UPS and retail delivery trucks such as Safeway, Frito-Lay, and beer distributors.
This project aims to create a tool that makes urban freight easier to understand. Ken Ogden claims, "To a greater degree than in urban passenger transport, the urban freight task is enormously complex and heterogeneous." (Ogden 1992, p. 4) Ogden's characterization may be overstated, since trucks originate in a more limited number of locations than automobiles and operate largely in a planned and controlled manner based upon economic rationality. Despite the variations across enterprise operations, the rationality inherent in truck movements may make them easier to portray and understand than personal vehicles that move about according to the daily scheduled and unscheduled activity demands of consumers.
The starting point for the RFLP is to provide documentation to MPOs, political leaders, and citizens on changes in operating patterns for delivery trucks on urban streets -- how many trucks, what kind, where they go, and when.
Because of our focus on urban impacts, we will develop an approach that describes and quantifies truck vehicle flows between representative origins and destinations within a metropolitan area, rather than using commodity data. Commodity flow data are now collected every five years by the Census Bureau, and these data establish the weight, economic value, and shipping distance of what is being moved by trucks down to the geographic level of metropolitan regions. For example, the 1997 Commodity Flow Survey establishes that 83 percent of the 100 million tons of goods shipped by truck from establishments in the San Francisco Bay Area was sent to destinations less than 50 miles away, a finding that again highlights the predominantly local nature of trucking (U.S. Census Bureau 2000). Commodity flow data can be analyzed to reveal the intercity and interstate patterns shown in See Nationwide Truck Freight Flows, but the data are not sufficiently disaggregated to reveal any detail on truck movements between origins and destinations within a metropolitan region.
Whatever the value and weight of the load, the economic contribution of a truck is influenced by how congestion reduces delivery speeds and creates variation in arrival times. Rather than make the subjective determination of what is or might be sufficiently fast and reliable delivery of goods and services to dispersed locations in a congested travel environment, we will strive to measure the more objective and fundamental fact of the growth in the volume of urban trucks and where and when they make their delivery stops.
Taking the Seattle region as an example, the Seattle Times reports that the movement of freight between the separate industrial locations of Boeing is significantly impacted by traffic congestion.See Kyung M. Song, "Boeing weighs long haul on region's clogged roads" Seattle Times, March 25, 2002 An increasingly congested metropolitan area is building up over time among Boeing's operations dispersed within the central Puget Sound metropolitan area. The RFLP will be a tool that places Boeing's freight mobility problem in perspective. Year by year, how many trucks does Boeing dispatch, where do they go, when do they move? A Boeing freight manager revealed to the Puget Sound Freight Mobility Roundtable in January 2003 that the annual trip count for one kind of delivery truck used for interplant freight movement is down 24 percent from 1995 to 2001. On-time performance for these trip types is measured to be 96 percent. However, there is no ongoing context for measuring the performance and regional impact of Boeing's fleet or any other. By setting up a process to track the changes in the movement of key regional truck fleets, the RFLP tool contributes to the ability of decision-makers to ferret out whether deterioration in freight flows is such a significant problem that it can be considered a contributor to plant relocation decisions.
The choices that a truck-using firm has are industry- and enterprise-specific. The RFLP's method to measure and understand these is to track the visible impact of these changes by describing truck operating patterns, including time of day, routes, origins, and destinations, in a way that can be monitored for year-to-year shifts.
If FedEx wants to make package pickups in a central business district during the late afternoon peak period, they will have to deal with congestion, and so will a manufacturer putting trucks onto crowded road segments during the morning peak. We want the RFLP to fully recognize and measure the options that businesses have in dealing with increasing delays and variability. For example, manufacturers and other truck-dependent enterprises have the option of relocating their facilities. Service industries dependent on afternoon FedEx shipments that have increasingly earlier pickup deadlines have the option of moving closer to the FedEx terminal. Frito-Lay, Coca-Cola, and other food and beverage companies dispatching delivery trucks to retail outlets throughout the region have a choice on where to locate the dispatch point.
The RFLP will also be designed to reveal data that illustrate the phenomenon of firms relocating because of congestion, if the phenomenon exists. The rise of new firms on the metropolitan periphery will also be measured to illustrate the private sector response to the traffic congestion that makes locations in more central areas less efficient.
These companies have other choices that do not include moving facilities but rather making operational changes -- using more trucks and drivers, changing hours, or forcing customers to change their expectations. We intend the RFLP to reveal these choices as well. The RFLP also needs to go beyond the economic effects of congestion on travel times and arrival variability. The story of freight from a comprehensive public policy perspective combines economic contribution and environmental externalities. The RFLP must consider all significant public policy issues, economic or environmental. For example, deterioration in air quality from diesel emissions is emerging as a public health problem in Seattle and other metropolitan areas.See Welch, Craig, "Dirty diesel emerging as big threat to area's air," Seattle Times, May 5, 2002
Any changes in truck operations, whether by private initiative or new government regulation to improve enterprise economic efficiency, may also change the level of environmental impacts. Examples include trucks making noise at an earlier hour, the volume of trucks increasing on particular streets, and changes at a delivery or dispatch point expanding its impacts on parking or local congestion in a neighborhood.
In addition to characterizing fleets and their movements, we see detailed descriptions of a representative sample of trucking activity nodes such as shopping centers (leading goods destination) and warehouse/distribution center clusters (leading goods origin and destination) as an important component of the RFLP. Learning how the number and location of these nodes change from year to year would be illuminating.
Regional entrances, start-ups, moves, and closings of truck-dependent businesses at the selected centers should be monitored in the RFLP, which becomes a starting point and prelude to in-depth investigations on the relationship of these business changes to congestion.
In focusing on specific locations, the RFLP should generate data that describe how trucking operations cause congestion around what might be considered inappropriate locations for a facility and its related truck operations.
Problems, Issues, and Opportunities
Our broad goal in creating the Regional Freight Logistics Profile is to support public policy design and implementation that improves the overall social cost-benefit ratio of urban freight [Ogden 1992]. This goal has two components: improving the economic performance that is the result of freight movement, and managing the environmental and other external costs of trucking in a socially beneficial way. Freight goals can also be examined by comparing the views of businesses using trucks with those of government agencies. After we examine these four components, we present a framework for analyzing freight and a preliminary design of RFLP coverage.
Improving economic performance
Reducing the costs of regional freight movement relative to other regions provides two economic benefits. First, a region gains a competitive advantage in shipping performance over other regions, which shows up in better business performance -- lower prices or better service to customers, for example -- resulting in enterprise growth and thus economic growth for the region. Second, enhanced shipping efficiency contributes on the margin to a higher regional standard of living, as resources formerly devoted to freight are freed up and reallocated to other demands.
With respect to regional competitive advantage, growing traffic congestion that slows the movement of freight or adds uncertainty to delivery times is a cost generator that takes regional freight performance in a negative direction. For example, rising urban traffic congestion can cause an afternoon deadline time for pickup by an overnight package delivery firm such as FedEx to be moved earlier so that trucks can reach the airport on schedule. If the FedEx office in a particular city needs to move up its package pickup deadline from 5 p.m. to 4:30 p.m., then the increasingly congested city becomes economically disadvantaged relative to other cities where congestion is not changing the deadline.
In regard to the effect on standards of living, if the cost of truck deliveries to retail stores for a particular region is unusually expensive, the costs of goods and services in those stores will tend to be higher. This means that the standard of living would be lower than in another region where trucking costs are lower.
Managing environmental and social costs
In moving freight and achieving the benefits that come from timely and efficient delivery of goods, trucks affect the environment surrounding their operations in ways that society judges as harmful for various reasons. For example, trucks cause pollution from their power train and brake lining emissions and generate noise and vibration beyond that generated by smaller vehicles; some people think they cause aesthetic blight.
Noise and vibration are exacerbated and objectionable to the degree that trucks operate at night and in residential areas. The need for operational efficiency and guaranteed delivery times will create more pressure for evening and late-night deliveries, when personal automobile traffic is less of a constraint on urban truck movement. On the other hand, increasing nighttime truck traffic in some North American jurisdictions has caused a political call for regulations that restrict night operations so that people who live near places where trucks deliver and move about do not have their sleep interrupted by truck noise.
One obvious impact of truck movement is its contribution to traffic congestion on roads and highways, especially in peak periods. Trucks mixing with personal vehicle traffic contribute to congestion for all traffic. In stop-and-go traffic, large trucks disrupt the flow by acceleration and stopping characteristics that are markedly different from autos and small personal trucks. Large trucks also take up more road space than passenger vehicles.
Congestion results not only from trucks being on the road in peak periods, but also from the disproportionate number of accidents caused by heavy trucks. Truck accidents generate social and economic environmental impacts in the form of deaths, injuries, and property damage. Accidents can be significant because of the weight of the truck or as a result of a flammable or toxic load.
The public cost of providing and maintaining the road infrastructure that supports trucks can also be considered an environmental impact. Although most of the road use on most segments is personal vehicles, some characteristics of roads are the result of accommodating trucks. Examples of these characteristics include pavement that supports heavier vehicle weight and the special road geometry that accommodates the heights, acceleration, stopping distances, and turning radii of trucks.
Trucks can and do add to congestion on urban arterial streets because of inadequate facilities for loading and unloading at delivery points. Depending on the configuration of the facilities at a delivery stop, trucks may have to load, unload, arrive, or depart in ways that interfere with the movement of other vehicles on the public right of way. Poor facilities cause impediments to the flow of vehicles on public roads from intrusions of stopped trucks or from backups of waiting trucks, for example, loading zones along the curb can be inadequate, and there may be insufficient private truck parking for loading and unloading. Private passenger vehicles may illegally take up space meant for trucks in commercial loading zones if regulations are not enforced. In urban environments, trucks often are stopped for a delivery in a traffic lane.
The last environmental impact from trucking that we will note derives from the linkage between truck transportation and land use. Trucking generates some characteristic land uses -- fleet maintenance bases, large distribution centers, intermodal terminals, for example -- that have large land footprints, environmental impacts, and a spatial orientation to widespread metropolitan area destinations that make suburban locations preferable to center city locations. The requirement of stores and office complexes to take truck deliveries at frequent intervals also creates land use configuration requirements for truck access at all metropolitan locations where commercial activity is sited. Many aspects of land use, such as allowable uses, size of facilities, and traffic mitigation actions, are subject to state or local government regulation in the form of building and zoning codes.
Business Point of View on Freight Goals
Business organizations and the trade associations that represent them see freight movement as one of many functional components that bear on serving customers well and profitably. Stores need to stock their shelves, wholesalers need to ship the products that customers order, and factories need to receive parts and ship final goods. Trucks carrying freight do this. Enterprises work to improve freight and logistics within a competitive market environment to meet business goals -- typically growth in sales, market share, and profits -- while seeking lower costs and greater efficiency.
Enterprises generally seek efficiency (or productivity) of freight transport operations, including dealing with traffic congestion and loading and unloading delays, in order to reduce costs. Costs are generated in the delivery itself and in coordination with other operations. Enterprises that move freight to commercial facilities such as factories, stores, and warehouses usually need to operate in coordination with operations and resource availability at receiving locations. The production line needs parts to keep assembly going; an unloading crew finishes with one truck and is ready for the following one. Generally, urban delivery trucks across many sectors must aim to arrive at stops for loading and unloading during scheduled time windows that are 15 minutes to 2 hours in length. Arriving too early and arriving too late may be equally undesired. Deliveries to homes are somewhat less sensitive to arrival times than commercial deliveries, but good customer service requires schedule discipline for residential deliveries as well.
On the multiple stops of a delivery tour, congestion can both affect the average driving time between points and add to variability in the time to drive, thus creating uncertainty in the time of arrival. These are two distinct issues. A predictable level of congestion can be handled by allowing more time in the schedule, as can a variable but predictable level of congestion, for example, a delivery environment where congestion is known to be bad on Fridays or when there is rain. If the variability is high and unpredictable, the rational response in scheduling resources is more difficult because it depends on the costs of being unpredictably late versus unpredictably early at a delivery point, and how often each occurs.
Traffic congestion causing delay and uncertainty in the timing of deliveries and pickups is an ongoing private sector challenge that adds complexity and cost to operations. All other things being equal, deteriorating delivery performance following on-time dispatching often signals a rise in traffic congestion that is adding to delay and uncertainty in travel times. Logistics managers must deal with congestion in practical, short-term, self-help ways, since relief from public sector action to reduce congestion -- building new roads or retiming traffic signals -- is typically slow in arriving.
Time-of-day operating patterns are one parameter that business managers can change, if the workforce is willing. Trucks can be dispatched at earlier or later times that are more likely to keep them off the road during morning and afternoon peak periods. The order of stops may be flexible. Arrival time windows for deliveries can sometimes be enlarged, or loading docks expanded, in recognition of the uncertainty in arrival times that cause too many trucks to arrive simultaneously. Changes in truck arrival times may require changes in the operating hours of shipping and receiving departments that trucks serve.
Drivers can be provided with technology that alerts them to traffic congestion and then allows them to alter their delivery route patterns to minimize time spent in traffic. This technology can involve data displays of traffic conditions or the sharing of traffic information among drivers via voice radio or cellular telephones.
Operational patterns can be reengineered in response to congestion. Changing origins and destinations is one possibility. Facilities can perhaps be expanded at or relocated to locations where traffic congestion has a lower effect on truck movement. A retail chain that sells merchandise from multiple vendors may need to establish a receiving point on the periphery of a metropolitan area at which loads from multiple suppliers can be consolidated for delivery by a smaller number of trucks to stores in congested central areas.
Another kind of reengineering would be to reduce the dwell times for deliveries, to provide extra time on the road in response to congestion. If there is sufficient space, a delivery might involve dropping off a loaded trailer and picking up an empty one from the last delivery. Goods could be packed to yield faster loading and unloading times.
Another form of reengineering that might be used is to change freight transportation modes from trucks to railroads, barges, a pipeline, or a conveyer belt, for example. This can be done partially to move freight in and out of a congested region. A new rail line to the waterfront docks at a container terminal might reduce road traffic from trucks going to those docks.
Business Site Location Decisions
Businesses seek to have deliveries at some standard of efficiency for the company and reliability for customers, but performance along these dimensions trades off against important cost variables including labor, equipment, and facilities, plus the cost of implementing changes. A firm may not have the flexibility to change the geographic location of a facility. A retail chain that decides to serve a congested urban market must cope with the delivery challenges.
Road transportation conditions, including traffic congestion, is just one of many considerations that managers take into account when choosing the locations of facilities. Factors that once made a site suitable can change and prompt a relocation of the facility. An area of a metropolitan region, such as a waterfront industrial zone, may evolve over time to have more commercial or residential characteristics, thus making a trucking-intensive operation that was once appropriate become ill-advised. A parts supplier to a major manufacturer who starts out with operations in a distant part of town may be asked by a major customer to move closer, thus reducing shipping distances. In the Puget Sound region, grocery store chain Safeway is relocating its distribution center from a crowded location in suburban Bellevue to one in the Kent area where many other distribution centers are located.
If traffic congestion cannot be avoided and delays slow down operations, more trucks and drivers may deploy, with each truck making fewer stops to achieve the same amount of freight movement. If too many firms react this way in a region, a death-spiral dynamic can be created. When more congestion motivates a business to add more trucks to the delivery fleets, more congestion is created for existing trucks. The downward cycle continues with more trucks added to compensate for increasing congestion and delay, yielding more congestion, and so on.
Still, for any given enterprise, there may not be a budget for more trucks and drivers. A firm may choose to live with deteriorating freight mobility for a period of time until the public sector can make investments that will improve the situation.
Managers and owners of business firms that have freight delivery as part of their operations also have a range of opinions about the environmental externalities of trucking as they bear on the interests of their own enterprise. The relationship of business enterprises to environmental regulation is complex, but in most cases, environmental externalities are not a primary focus in most of the private sector, unlike in the public sector.
While the business requirement for freight movement is the main force behind trucking and all the environmental impacts it creates, businesses are not necessarily insensitive to public reaction and government regulation of these impacts. It is a commonplace to say that they want clear, fair rules that, if applied to them, also apply to their competitors.
As a general rule, any business associated with trucking wants roads to be safe and adequate to the job of getting trucks to where they need to go. They want traffic operations and other trucking-related service to be applied in locations that meet business requirements.
For a firm deciding between two or more metropolitan areas in which to establish a trucking-intensive facility, such as a distribution center or manufacturing facility, transportation infrastructure and road congestion around potential sites are typically just two of many considerations in the eventual decision. Bad traffic in a particular region may be mitigated by lower labor or energy costs in that region, or even management preferences on where they want to live. If all factors were exactly equal except transportation, the transportation issues might be deciding, but rarely is a site location decision this easy.
The land use characteristics generated by truck-based operations are certainly more tolerated by the enterprises that need these patterns than by the public at large.
Freight goals from the viewpoint of the public sector
Unlike the narrow focus that enterprise managers take on serving owners and customers, government managers are charged with serving the public more generally and thus must adopt a broader focus that recognizes the externalities that affect the lives of all citizens, in addition to support for a healthy economy.
Government has a responsibility to provide the publicly owned physical facilities and services that provide freight transport operations, especially constructing and operating the roads and bridges over which trucks must pass. To keep their geographic jurisdiction functioning efficiently, governments have an interest in zoning and building code regulations that specify the permissible locations and configurations of facilities for loading and unloading commercial trucks. On a multijurisdictional regional basis, metropolitan planning organizations conduct planning processes that provide some direction to municipalities and counties on which infrastructure should be built next.
In addition to planning and implementing transportation infrastructure, local governments and regional planning organizations often have a mission of supporting regional economic development, which means planning and taking action across a broad front to support job creation by the private sector. This means influencing private enterprises to expand and relocate in target areas and to retain existing firms. This influence sometimes includes working with transportation authorities to make sure that trucks can move efficiently throughout the region. Government economic development activities attempting to influence the path of the economy typically are coordinated with other government interests.
In the public sector's oversight of land use, authorities might try to persuade trucking-intensive firms that want to move a facility in or out of an urban district to be aware of market trends and the intent of land regulation activities as described by master plans. Firms might reasonably want to relocate away from an urban district because the congestion makes logistics difficult. For example, the City of San Francisco has evolved its waterfront away from marine cargo activity toward more commercial and tourist-oriented activities.
The government management of externalities is a balancing act between support for economic development and the other public interests that are affected by trucking. The noise, vibration, emissions, additional traffic congestion, and occasional accidents caused by trucks are seen as a price for the benefits of economic activity that trucks support, but government usually attempts to put some limits on these impacts. An example of achieving balance is land use zoning to put business facilities that involve trucking activity into geographic areas where residential areas will not be disturbed.
On the other hand, all governments seek to improve the accident record of trucking. Safety is a goal accepted by businesses as well, subject perhaps to economic conditions that sometimes cause too little investment in maintenance and driver training, raising the probability of accidents.
The public sector also is responsible for the performance of society in emergencies. When natural disasters, terrorist attacks, and other emergency conditions strike, people assume that government will ensure that basic human needs for food and medical supplies are met through freight delivery, even if roads are disrupted. In Washington State, the occasional seasonal experience of simultaneous blockage of Highway I-5 leading into Seattle from the south and I-90 into Seattle from the east because of flooding and snow respectively has illustrated that shortages in retail grocery store stocks occur within three days.See Bob Oenning, Washington State Department of Emergency Management, personal communication.
Framework for analyzing freight
As discussed in See Introduction to Urban Freight Movement, there are three demand factors in freight movement:
D1: Goods, cargo, what is moved
D2: Land use, or origins and destinations
D3: Business processes governing freight, determined by enterprise
There are four supply factors in freight movement:
The following are all the interactions of the basic factors in supply and demand:
D1 with D2: Land use interacts with cargo: Freight generation
D1 with D3: Cargo interacts with business process: Enterprise design
D1&D3 with S1&S4: Cargo and business process interacts with networks: Freight flows by mode
D1&D3 with S2: Cargo and business process interacts with vehicle: Vehicle design
D1&D3 with S3: Cargo and business process interacts with vehicle movement: Vehicle loading
D2 with D3&S1&S4: Land use interacts with business process and networks: Site location decisions
D2 with S2: Land use interacts with vehicle: Building site design for freight loading/unloading
D2 with S3: Land use interacts with vehicle movement: Trip generation
S1 with S4: Road interacts with nonroad: Intermodal transfers
S2 with S1&S4: Vehicles interact with networks: Roadway and other transport infrastructure design
S2 with S4: Vehicles interact with vehicle movement: Freight industry structure
S3 with S1&S4: Vehicle movement interacts with networks: Freight flows on roads and nonroads
Ordering of Freight Components by Amount of Public Policy Influence
We can assign the various freight interactions from the previous section into categories that reflect the amount of public policy influence.
High Influence: Transportation Infrastructure Investments
Public policy heavily influences road investments, which are required because vehicles interact with transportation networks (S2 with S1&S4). Road infrastructure design to support trucking must permit truck movement without unreasonable restrictions. The design of roads is influenced by the turning radius, weight, and dimensions of trucks. Features that must respond to these characteristics of trucks include overhead clearances on bridges and other underpasses, pavement thickness, strength of bridges, design of railroad crossings, truck lanes on uphill grades, transit design, and the location of public facilities such as sports stadiums in relationship to high truck activity areas.
The following infrastructure design issues are related to causing delays for trucks: