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55 Establishment Survey--San Bernardino Valley through 1977. However, the CFS represented an important improvement in method, sample size, and scope over the ear- Following on the experience of the Calgary survey, the lier surveys (42). importance of considering both the sampling base and the recruitment method is illustrated further by an establish- The CFS is a nationwide survey of business establish- ment survey that was conducted of local trucking companies ments in selected industries, specifically in mining, manu- and shipper/receiver businesses in the western San Bernar- facturing, wholesale trade, and selected retail and services dino Valley region (California). Questionnaires were sent to establishments (auxiliary establishments). An establishment 405 businesses, which were identified through the California is defined as "a single physical location where business trans- Trucking Association and the cities of Ontario and Rancho actions take place" (42). The CFS supplies data on the flow Cucamonga. Of these, 37 responses, or 9%, were returned: of goods generated by the sampled establishments by mode the low response rate was attributed as being "typical" of of transportation in the United States. Data are provided on this type of survey and also because of "other recent sur- tons, miles, ton-miles, value, shipment distance, commodity veys" (on unspecified topics) that might have led respondents type, and weight. All major modes of freight transportation to view this survey as redundant. It is not clear whether or are captured (43). not direct follow-up contacts were made or if assistance was provided. Moreover, the survey was shorter and less detailed A sample of establishments is drawn across all 50 states and required less specificity (in terms of shipment type and and the District of Columbia. Participation by sampled estab- origin and destination addresses) than, by comparison, the lishments is mandatory because it is linked to the 5-year Calgary and Edmonton surveys (40 ). Economic Census. The sampling frame is drawn from the Census Bureau's Business Register of approximately 6 mil- Online Establishment Survey--Atlanta lion establishments, of which approximately 754,000 estab- lishments (in 2007) were in the industry categories covered The 2008 Atlanta Regional Freight Mobility Plan provides an by the CFS (44). The sample dropped steadily from 200,000 example of the use of online surveys for conducting an estab- establishments in 1993 to 100,000 in 1997 and 50,000 in lishment survey. This survey was part of a series of data col- 2002 (43). However, it increased back to approximately lection activities, and sampled shippers and carriers that were 100,000 establishments in 2007 (44) (i.e., in effect doubling considered to be "major freight generators" in the Atlanta the sample from 2002, as the total number of candidate region. The survey captured information regarding business establishments was approximately the same in both years). type; the number of deliveries to warehouses, distribution centers, and businesses; the day of week and (typical) time A stratified three-stage sampling process was used in the of day of deliveries; the number of inbound and outbound 2007 CFS (and also previously), as follows (44): loads and shipments; and the destination of loads (used to determine routings within the region). A commercial online Establishment selection. The sampling frame was first survey tool was used, which allowed variations of the survey stratified by geography [accounting for the 50 states, to be distributed to different groups: shippers and receivers, the District of Columbia, and 65 metropolitan areas transportation carriers and operators, and the general public. (the last according to population and importance as There were 74, 24, and 31 responses respectively. The results transportation hubs)]. Within each geographic strata, were not used for detailed modeling and were combined with 48 industry groups were defined (i.e., within the can- other data--including commercial (TRANSEARCH) com- didate industry types) according to the 2002 North modity flow data and roadside interviews--for analysis (41). American Industry Classification System). Separate As noted, the sample was limited to "major" generators; and strata of hazardous materials shippers also were cre- no indication is given that a statistically viable sample was ated to gain more information on these shipments. The drawn for the "general public." Nonetheless, the study dem- combined geography-by-industry stratification resulted onstrates the potential of online surveys as a data gathering in 2,745 primary strata. Based on these strata, a sample tool and also as a means of engaging the "public" regarding size of 102,369 establishments ensured a minimum of 2 its freight-generating activities. samples and a maximum of 100 samples per stratum. Reporting week selection. The sampled establishments were asked to report on 4 weeks--one in each calendar COMMODITY FLOW SURVEYS quarter for 2007 (i.e., January 6, 2007, to January 4, 2008). Because different establishments were assigned different The Bureau of Transportation Statistics (BTS) and the times, the sample covered all 52 weeks of the year. Bureau of the Census conduct jointly nationwide Com- Shipment selection. If respondents made more than 40 modity Flow Surveys (CFS) at approximately 5-year inter- shipments per week, they were asked to conduct a sys- vals (1993, 1997, 2002, and most recently in 2007). Freight tematic sample to report a minimum of 20 shipments characteristics were captured in earlier surveys, from 1963 and a maximum of 40 shipments. If respondents made