A Concept for a National Freight Data Program Special Report 276 (2003) / Chapter Skim
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2 Freight Transportation Data: Current Limitations and Need for a New Approach
2 Freight Transportation Data: Current Limitations and Need for a New Approach
Pages 36-50
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From page 36... ...
from the Bureau of Transportation Statistics and the Census Bureau, the Rail Waybill Sample from the Surface Transportation Board (STB) , the Vehicle Inventory and Use Survey (VIUS)
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From page 37... ...
However, transportation analysts seeking to use data from these diverse sources often encounter problems that detract from the usefulness of the available information. The following are among the problems: · Variations in reporting that complicate the interpretation, comparison, and combination of data from different sources; · Incomplete coverage of freight movements; · Lack of geographic detail, particularly at metropolitan and local levels; · Lack of information on data reliability; and · Difficulties in using databases designed for purposes other than transportation analysis.
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From page 38... ...
The PIERS database on waterborne freight includes O/D data taken from vessel manifests listing addresses of the shipper and consignee, although it does not include information on shipment routing or landside modes used in transporting shipments to and from inland origins and destinations. Historically, the biggest problem with the PIERS O/D data has been confusion between the location of the owner or bill-to party and the physical origin or destination of the shipment.
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From page 39... ...
Shipment Characteristics Different industries and transport modes use different measures of shipment size -- differences that are reflected in freight and trade databases. Although shipment weight is widely used, commodity-based sources often specify shipment volume and may use specialized volumetric units (e.g., bushels of grain, barrels of petroleum)
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From page 40... ...
Trade databases use product-based classification systems such as the Harmonized Schedule of Foreign Trade (HS) and the Standard International Trade Classification, whereas transport-oriented databases use classifications such as the Standard Transportation Commodity Classification and the Standard Classification of Transported Goods (SCTG)
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From page 41... ...
Incomplete Coverage Although transportation and trade databases provide considerable amounts of data on freight activity, some aspects of freight movements are poorly characterized -- at least using publicly available data. In particular, · Coverage of different economic sectors and transportation modes is uneven; · Coverage of international shipments is incomplete; and · Some specific items of information, such as travel time from origin to destination, are reported only infrequently.
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From page 42... ...
. Some of these gaps can be filled by using data from sources covering single modes, such as the Rail Waybill Sample and the Corps of Engineers and PIERS databases on waterborne freight, all of which provide comprehensive coverage across economic sectors.
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From page 43... ...
(CFS = Commodity Flow Survey; STB Waybill = Surface Transportation Board's Rail Waybill Sample; COE = Army Corps of Engineers' Waterborne Commerce of the United States database; PIERS = Port Import Export Reporting Service database. Source: Rick Donnelly, PBConsult, Inc.)
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From page 44... ...
There is an outstanding requirement for more focused data on freight movements at the metropolitan level to provide insights into transportation demand, the relationships between freight movement and business patterns, and freight flows through key corridors (BTS 1998)
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From page 45... ...
The information needed by local decision makers far exceeds the capacity of any single national survey, and local data collection efforts that supplement national surveys appear to be a more promising approach to remedying the current lack of detailed geographic data (BTS 1998)
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From page 46... ...
In many cases, little information is provided about the assumptions used in generating derived data products, with the result that their reliability is unknown. Difficulties in Using Databases Designed for Other Purposes Commodity flowtype freight databases typically include data on commodity type, shipment origin and destination, shipment weight, and shipment value for one or more modes of transport.
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From page 47... ...
While such surveys provide reliable vehicle data and relatively accurate commodity data, they cannot provide data on commodity value -- data that are critical to informing investment decisions and building linkages with economic input/output models. In light of the economic importance of trade with the United 2For further discussion of trade databases and the two major categories of freight database (commodity flow and supplementary)
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From page 48... ...
, the study committee initially considered the possibility that a comprehensive national picture of freight flows might be developed by combining existing data sources without the need for modifications to current data-gathering procedures or additional data collection initiatives. The committee quickly concluded that creating a comprehensive national freight database by patching together existing data sources is not feasible.
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From page 49... ...
A concept for a national freight data program that aims to meet these ambitious goals is presented in the next chapter. 5ITDS Background (www.itds.treas.gov/itdsovr.html)
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From page 50... ...
1997. NCHRP Report 388: A Guidebook for Fore casting Freight Transportation Demand.
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