Quick Response Freight Manual II
The Federal law governing planning for transportation planning (23 USC 133 and 23 USC 134) as well as for transit planning (49 USC 5303 and 49 USC 5304) requires that states and metropolitan planning organizations (MPOs) consider freight in their long-range plans, transportation improvement programs, and annual work elements. There are, however, some issues that must be addressed before the states, MPOs, and other planning agencies can be effective in freight planning:
- Most of these agencies have more experience considering the movement of passengers rather than the movement of freight;
- Current and historical data on freight, especially truck movements, are extremely limited; and
- Most of the models in the literature are highly complex, and require data that are not generally available to planning agencies.
The objectives of this Manual are as follows:
- To provide background information on the freight transportation system and factors affecting freight demand to planners who may be relatively new to this area.
- To help planners locate available data and freight-related forecasts compiled by others and to apply this information in developing forecasts for specific facilities.
- To provide simple techniques and transferable parameters that can be used to develop freight vehicle trip tables. Trucks carrying freight on the highway can then be merged with other truck and auto vehicle trip tables developed through the conventional four-step planning process.
- To provide techniques and transferable parameters for site planning that can be used by planners in anticipating local commercial vehicle traffic caused by new facilities such as regional warehouses, truck terminals, intermodal facilities, etc.
The Manual addresses freight issues at different levels of analysis. On the more detailed site planning level, the methods include predicting the number and temporal distribution of truck trips to and from specific locations and identifying the routes used. On a more aggregate level such as corridor, metropolitan area, or regional level, the Manual helps develop forecasts of trips generated by various traffic analysis zones and distribute these trips to the transportation network.
The analytical methods contained in the Manual place special emphasis on the inclusion of transferable parameters that can be used as default values for model inputs when data specific to the state or metropolitan area are not available. In developing these methods, the circumstances giving rise to those parameters, such as geographic location or the industrial function, will be considered.
This Manual also identifies alternative analytical methodologies and data collection techniques in order to improve the accuracy of the freight analysis and planning processes.
If passenger transportation can be broadly defined as the movement of people, then freight transportation can be broadly defined as the movement of goods from one place to another. However, freight as it is used in many economic analyses, including this Manual, define freight more specifically as the movement of goods from a place of production to a place of consumption in support of manufacturing processes. The surveys using this definition of freight specifically exclude goods moving to service establishments, construction, most retail industries, farms, fisheries, foreign establishments, and most government-owned establishments. On a geographic level, this definition of freight transportation is of most use when considering the movement of goods between metropolitan areas. Transportation planners are not only concerned with the shipment of these goods, but also need to consider the movement of goods within metropolitan areas. This may include the delivery of goods to the excluded industries as well as the movement of goods that are ancillary to the main purpose of the trip, such as service, utility, and construction trucks that carry goods to support their activities. For that reason, this Manual discusses methods that consider all movements of goods, whether over long distances or local deliveries, part of manufacture or trade, or are merely incidental to other activities.
The Manual is organized in four parts with each divided into sections. Each section is independent of the others, and the user may read the section or sections that best serves his or her interests. The following describes the components of this Manual:
Part A consist of those sections that provide an Introduction to the material. It consists of this section, and:
- Section 2.0: Freight and Commercial Vehicles Demand: Controlling Factors – This section describes how an understanding of the controlling factors for freight can help identify issues to be addressed in forecasting. The factors to be discussed include:
- Why freight moves – The Economic/Industrial/Commodity factors that give rise to the demand for freight;
- Who moves freight – The Logistic factors that determine the spatial relationships, shipment sizes, and frequencies that determine between shipper and receivers, the size and frequency, and other factors governing shipments;
- What moves freight – The Modal factors that determine the costs and service levels covered by the modes that carry freight: truck, rail, water, and air [Large flows of freight are also carried by pipelines. Pipelines are not addressed in this Manual because the commodities carried, generally petroleum and other liquid products, are specialized and unique to pipelines, data on the distribution network and flows is not readily available, and the flow of goods by pipeline rarely is addressed by the transportation audience for whom this Manual is intended.];
- Where freight moves – The Vehicles/Volumes factors that are concerned with the movement of freight inside vehicles on the various modal network; and
- How freight moves – Public Policy that sets the rules and regulations under which freight must operate.
Part B consists of those sections that cover the Methods of freight forecasting – from simple factoring methods; to methods that incorporate freight forecasting in traditional transportation modeling in urban, state, and site settings; to commodity flow methods that utilize multimodal freight demand to forecast freight demand:
- Section 3.0: Simple Growth Factor Methods – This section describes how growth factor methods can be used for forecasting freight demand using historic trends, using regressions based on single and multiple independent variables, and using growth factors as applied to tables of freight flows.
- Section 4.0: Incorporating Freight into “Four-Step” Travel Forecasting – This section addresses how the traditional “four-step” transportation forecasting process (Trip Generation; Trip Distribution; Mode Split/Conversion to Vehicle Flows; and Network Assignment) is used to forecast goods movement in the traditional urban transportation planning models, in state transportation planning models, and in site planning. The methods discussed in this section consider the different definitions of freight transportation discussed in Section 1.2. The methods used in urban and site planning generally consider all trucks as freight trucks, while the state models use the commodity definition of freight.
- Section 5.0: Commodity Modeling – This section discusses how acquiring a table of goods movement, defined by commodity can be used in freight forecasting. The issues covered include how to obtain a table of commodity flows, the geographic issues of the tables, and issues with disaggregating or factoring the flows.
- Section 6.0: Hybrid Approaches – This section discusses, in particular for urban truck forecasting models, how the different methods discussed for trucks in urban areas in Section 4.0 can be combined with multimodal commodity methods appropriate for state modeling as discussed in Section 5.0 or the commodity flow methods of Section 5.0 to forecast flows with at least one external trip end. This discussion will include the issues associated with logistic nodes (e.g., terminals) where external flows are distributed to internal zones.
- Section 7.0: Economic Models – This section discusses how freight forecasting can be included within more comprehensive economic/land use/ecological models such as Puget Sound Regional Integrated Simulation Model (PRISM), UrbanSim, etc.
- Section 8.0: Model Validation – This section discusses the special considerations in validating freight models, especially those with borrowed parameters. Consideration is given for how to calibrate freight models and forecasts (how well models correspond to existing conditions); and how to validate freight models (how well models correspond to expected changes). Consideration is given to the sources of validation and calibration data for freight forecasting. This section discusses the steps of freight models where changes can be made to improve calibration/validation.
Part C consists of those sections that discuss the various Data Sources that are available to support freight forecasting:
- Section 9.0: Existing Data – This section discusses the availability of data, the content of that data, and the advantages and disadvantages of using existing freight data. Particular attention will be given to how this data fulfills the needs identified in Part B to support the methods of forecasting. The data discussed includes: Commodity O‑D tables, including the Freight Analysis Framework, (versions 1 and 2), the Commodity Flow Survey (CFS), and TRANSEARCH; vehicle data such as the Vehicle Inventory Usage Survey (VIUS) and weigh-in-motion (WIM) data; modal usage data such as the railroad Carload Waybill Sample, or the marine Waterborne Commerce; Employment/Industry data such as County Business Patterns; and network performance data such as Intelligent Transportation Systems’ Traffic Monitoring System, Automatic Traffic recorder data, and vehicle classifications counts.
- Section 10.0: Data Collection – This section discusses why existing data may be insufficient and why new data may be required to support methods in Part B. Topics discussed include data collection issues such as sample sizes, and implementation issues for various types of supporting data collection: various types of new collection methods such as new vehicle counts; establishment surveys, diaries, intercept surveys, etc.; and methods to collect information about freight infrastructure such as field inspections of freight facilities, line-haul, and terminals.
Part D consists of sections that deal with Practical Applications of freight forecasting:
- Section 11.0: Application Issues – This section discusses the reasons why freight forecasts are needed, the development of alternatives to be tested, and their attributes and how these forecasts will be used in the transportation planning process. The use of freight forecasts in the transportation planning process will include not only the preparation of plans, programs, and projects but also how these forecasts can be used in support of management systems. Among the other application issues discussed are the availability of base data and forecast variables and the private versus public concerns for freight.
- Section 12.0: Case Studies – This section covers how methodological and data issues were addressed in actual case studies, organized by the scope of the geographic area addressed in the case study: state and multistate, both large and small urban areas; and individual sites such as ports, airports, industrial parks, and intermodal railroad terminals.
- Section 13.0: Intermodal Considerations, Including Drayage – This section discusses issues that are unique to the transportation of freight in the connections with nonhighway modes. Issues that must be considered in intermodal/drayage considerations include linked and unlinked freight flows in data and forecasting; container and bulk/trainload modal exchanges; and special considerations for truck-rail, truck-air, and truck-water issues. Additional issues covered in freight forecasting include time lags between modal exchanges; special equipment needs in intermodal and drayage handling; the logistics and operation of intermodal facilities; and the geographic markets for drayage services.
Finally, the Manual contains additional material in Appendices A and B:
- Appendix A – Glossary defines some of the most common terms used in freight planning and analysis. Appendix A includes an Acronym List.
- Appendix B – Classification Schemes provides in tabular format some of the more common classification schemes used in freight, including commodity classification schemes, industry classification schemes, and vehicle/truck classifications schemes. Also included in the appendix are crosswalk tables between different classification schemes covering the same topic, e.g., different commodity classification schemes.