Freight Transportation Surveys (2011)

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9 CHAPTER TWO METHOD FOR SURVEY AND LITERATURE REVIEW SURVEY OF PRACTICE Survey Development The survey “Freight Transportation Surveys—Existing Methods and Guidelines” was conducted primarily between May and October 2009. Before the survey was distributed, it was necessary to establish a comprehensive outline and test the survey to ensure that it was as accurate and target- specific as possible. During the initial stages of constructing the outline of the survey, it was decided that it would also be beneficial if the survey could be answered by several different types of agencies that are involved in the freight transportation data collection process. A logical way to construct the survey was to structure the questions as close-ended as possible, in order to provide a clear indication of what was being asked and to help in the summary process. Most of the questions were asked with a selection, or list, of answers, and the respondent was instructed to select a single answer or as many answers as applied, depending on the ques- tion. However, because of the nature of the subject, a stan- dard set of answers may not always have covered all the options. Accordingly, for most questions there was also the option to select “other,” with space provided to expand on the answer. The survey targeted the following key information: Who was the survey respondent?• What is the purpose or application for the freight trans-• portation survey(s) and/or data collection? What methods are used to collect the data?• What are the characteristics of the data being • collected? What public and/or commercial data sources are • used? What data are needed or unavailable? • What were respondents’ experience with their survey • practices and any other available data? This chapter documents the methods and assumptions for conducting the literature review and the survey. It discusses the research method, sources of literature, a practical review of the literature, and the purpose of and approach to the sur- vey in order to give a greater understanding of the process and of the subsequent findings. OVERVIEW OF METHOD The information upon which this synthesis is based was gathered in two separate tasks. The primary task was a sur- vey of practitioners, which was complemented by a literature review. The survey was sent primarily to all state DOTs, as well as to selected MPOs that were known to be active in freight transportation. The survey also was sent to select national agencies, port authorities, and commercial purveyors of freight data. This diversity in the survey group was intended to capture the viewpoints and experience on freight data collection activities from as many participants involved in the process as possible. Participants completed the survey online through a web-based survey program. The literature review began with a search for any resources that had the potential for further review. An online search was conducted using transportation resource web- sites and search engines to gather further resources. From this search, available electronic resources were gathered. This was complemented by contacts with Panel members, members of selected TRB freight committees, and selected academics to request resources that they believed might be relevant. The agency representatives were also asked if they would be able to provide any other sources of information (e.g., published reports, journals, articles, etc.) as well as any other individuals or organizations that might provide further assistance. Any leads that were obtained from discussions with other professionals were pursued to their end. The con- sultant’s internal library also provided valuable publications and reports.

10 The survey was divided into six self-contained sections. This made the survey more “respondent friendly,” in order to specifically target areas of interest in the process. Also, the survey was divided into sections because the online survey answers are only received after each section is completed; if the survey was only one section and the respondent “aban- doned” the survey partway through, no answers would be received. The first section determined the type of agency that was responding to the survey and who from that agency was responding. It also asked respondents what purpose and what transportation modes are considered in their freight trans- portation surveys and/or other data collection activities. Section 2 asked if the respondent’s organization adminis- ters or funds surveys or data collection initiatives to obtain freight data, and if yes, what techniques were used. For each technique used, the respondent was asked to describe the data collected. Section 3 asked respondents what are their freight data requirements by listing general and mode-specific freight data and by asking if they currently use the data, need data that are are not available, or have data that are not applicable. Section 4 determined which public and commercial data sources the respondent used, and to comment on their qual- ity and shortcomings. Section 5 asked what ITS technologies were used and what their potential is for integration with other data collec- tion initiatives. The respondent also was asked to comment on the benefits and barriers of linking freight survey and informatics data. The final section, Section 6, asked respondents to com- ment on their existing freight transportation data needs, what improvements need to be made to existing data sources, future intentions concerning expansion of their data collec- tion activities, and for any “lessons learned” from their sur- veying and other data collection experiences. Taking all these pieces together, Section 1 identifies the needs for freight data, and sections 2–5 depict the state of the practice (methods and sources). Gaps and needs are iden- tified throughout: comments on quality and shortcomings, barriers, availability of data and detailed assessments in sec- tion 6. Although the survey may have required a relatively long time for some respondents to complete (of the order of 40 to 60 minutes), most respondents could complete the survey in a reasonable amount of time. This was possible because an option was provided at the beginning of each new topic for respondents to skip nonapplicable questions using inherent conditional branching. Following approval of the draft survey by the TRB Proj- ect Officer, the consultant conducted a pilot survey session internally to assess the usability and readability of the sur- vey before sending it to all participants. Minor modifications were made to the survey following the pilot survey session. Subsequently, the survey was sent to all state DOTs, MPOs with potential freight data survey experience (as identified through the literature or by the Project Panel), and select national agencies, port authorities, and commercial purvey- ors of freight data throughout the United States. The survey was sent to each group by e-mail under the name of the TRB Project Officer. TRB and the Project Panel provided contact names and e-mail addresses of the respec- tive representatives from state DOTs, MPOs, port authori- ties, and national agencies, and the consultant provided contact names and e-mail addresses for the commercial pur- veyors. Follow-up e-mail reminders were sent to those who had not yet responded (which could be determined because each respondent could be tracked, confidentially) and fol- low-up telephone calls were made to state DOTs that had not completed the survey within approximately 2 months of the initial survey invitation. The follow-ups also ensured that the appropriate person(s) within each state DOT received the questionnaire. However, for reasons of confidentiality, these individuals cannot be identified. To expedite the entire process of distributing the survey and to facilitate respondents’ ability to read, respond to, and return it, it was decided that it should be distributed via e-mail. The practitioner was asked to complete the survey online through an online survey hosting company. A PDF version of the survey was included in the initial e-mail to enable the respondent to print the survey and review the questions before completing it online. Printing also assisted some respondents in gathering the information needed to complete the survey. To return the online survey, the partici- pant simply had to submit the responses by clicking a but- ton at the end of each section of the survey. The consultant provided support throughout the process by means of e-mail correspondence, as well as a toll-free telephone number that was provided with the survey. Upon review of the survey responses, telephone inter- views were initiated with selected respondents to follow up where additional information was required or to seek more information if an exceptional practice was identified. Appendix A presents the survey questions and a complete tabulation of responses to each question. (This question- naire, a web-only document, appears longer than the actual online survey, because the software structure incorporates branching and formatting that cannot be shown here.)

11 Sample and Responses The survey was distributed to all state DOTs, as well as to selected MPOs that were known to be active in recent freight planning activities. These were the primary intended audi- ence. To further broaden the coverage, the survey also was sent to selected marine and airport authorities, academics, and commercial freight data purveyors. In total, 74 individ- ual agencies were contacted. The greatest number of responses (46) was received from state DOTs. This number includes three DOTs that did not participate in the survey but that indicated separately that they are not involved in freight surveys (i.e., the subject was “not applicable” to them). This number also includes responses from two different offices of the California DOT, which chose to respond separately: in the ensuing discus- sion of the results, the two responses have been combined only where appropriate. Each of the other sampled agencies responded only once. The greatest rate of return was repre- sented by the 45 state DOT respondents, at 88%. Overall, 55 of the solicited agencies responded, for a response rate of 74%. Table 1 in the previous chapter presents the rates of return by agency type. SOURCES FOR LITERATURE REVIEW AND DATA The literature review and sources of data mainly focused on U.S. practice and experience. However, the freight transpor- tation surveys and data collection practices in several other regions such as Canada, the European Union, and Australia provided helpful insight on the state of the practice. In such cases, resources were also compiled based on international experience. Relevant publications and reports were located by vari- ous search methods, including the following five sources of information: Online Transportation Research Information Service • (TRIS); DOT and MPO websites;• Documents provided by DOTs, MPOs, academic insti-• tutions, and the Project Panel; Academic and practitioner contacts identified by the • consultant and the Project Panel; and The consultant’s internal library.•