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7Identification of Data Requirements, Resources, and Data Collection Capabilities The ability to conduct effective research and exposure- based risk analysis depends on successful data collection and database design. For a project like the development of the RID, which will support the largest naturalistic driving study ever completed to date, this required identifying and prioritizing the essential data for collection, determining the capabilities to collect these data, establishing the required accuracies per data element, and refining a quality assur- ance process to ensure data integrity. Development of the RID involved a progressive process with significant feed- back from the research community to address the following questions: ⢠Who are the potential users and stakeholder groups for the roadway data and GIS tools? ⢠What are the roadway data elements necessary to answer research questions using the RID and NDS data sets? ⢠What should the priorities be for collecting these data, existing data sets, or mobile mapping? ⢠What GIS needs are critical in maximizing user access to the RID data, given the range of user capabilities? 2.1 Identifying Data Usersâ Characteristics The strategy for identifying data users began with distin- guishing between users who will conduct their own analysis as opposed to those who will use predefined data sets and analysis tools. This information helped ensure that the appropriate data elements were identified and collected as part of the SHRP 2 data collection effort. In addition, the information aided in understanding the range of users of the data so that data sets, data integration tools, data dic- tionaries, and other products that resulted from this effort were available. Users were then further defined based on several factors, including level of familiarity with roadway data and familiarity with GIS and spatial analyses. This process helped the research team focus the RID design. 2.2 Identification of User Groups After identifying the usersâ characteristics, the research team identified specific groups of users and stakeholders who will use the SHRP 2 RID. Researchers who will use the RID data set will come from a wide range of backgrounds, including the following groups: ⢠Federal, state, and local agencies that use roadway data for decision making; ⢠Leading universities in transportation safety; ⢠Consulting engineering companies who conduct safety research; ⢠Traffic/highway safety engineers; ⢠Human factors researchers; ⢠Policy analysts; ⢠Statisticians; ⢠Social science researchers; ⢠Epidemiologists; ⢠Psychologists; ⢠Crash reconstructionists; ⢠Enforcement personnel; ⢠Emergency response personnel; ⢠Trade organizations; ⢠Asset management experts; and ⢠Highway operations experts. The users that most affected the RID design (including which data to collect) were the safety researchers with road- way data knowledge and expertise focusing on the roadway agencies (federal, state and local). Appendix A gives a detailed report on this effort. C h a p t e r 2
82.3 Identifying Data Needs This section describes the effort to identify the roadway data elements necessary to answer research questions using the SHRP 2 NDS. This effort included a broad range of safety- related research questions that may be asked by users. Appen- dix A gives a detailed report of this effort. The research team developed a comprehensive initial list of potential roadway data elements that may be relevant to a variety of analyses and uses with the NDS data. The team developed this list after conducting an exhaustive literature review to determine roadway data elements that have been identified in safety analyses and considering data necessary to answer the research questions related to intersection or lane departure crashes (high-priority research areas for SHRP 2). After the initial list was developed, the team obtained additional information from the relevant user groups. This information was obtained in several ways. First, the team reviewed roadway data elements that had been included in the following: ⢠Highway Safety Information System (HSIS), managed by the University of North Carolina Highway Safety Research Center under contract with the Federal Highway Adminis- tration (FHWA); ⢠Model Inventory of Roadway Elements (MIRE), main- tained by Vanasse Hangen Brustlin, Inc., and the University of North Carolina Highway Safety Research Center under contract with FHWA; and ⢠Model Minimum Uniform Crash Criteria (MMUCC), funded by the National Highway Traffic Safety Adminis- tration (NHTSA) and jointly managed by NHTSA and the Governors Highway Safety Association with input from other offices in the U.S. Department of Transportation. Data elements included in those inventories that had not already been identified were added to the list. A webinar was held in September 2010 that also solicited feedback from potential users. The initial list of roadway data elements was quite extensive, and, given limited resources available for mobile data collection, it was necessary to prioritize roadway data elements. The research team used a hybrid webinar/survey approach to refine the initial list and come up with a prioritized list. The list was further refined by the team based on expertise and feasibility analysis. The final list consisted of two tiers of critical items (Tier 1 and Tier 2), which were collected as part of the SHRP 2 mobile data collection project. The two tiers of data are as follows: ⢠Tier 1 44 Horizontal curvature: Radius, length, point of curvature (PC), point of tangency (PT), and direction. 44 Grade. 44 Cross slope/superelevation. 44 Lane information: Number, width, and type (e.g., through, turn, passing, acceleration, carpool). 44 Shoulder type/curb (and paved width, if it exists). 44 Speed limit sign location (R2â4 Series). 44 Intersection location. ⢠Tier 2 44 Intersections: Number of approaches and control (uncon- trolled, all-way stop, two-way stop, yield, signalized, roundabout). Ramp termini are considered intersections. 44 Median presence: Type (depressed, raised, flush, barrier). 44 Rumble strip presence: Location (centerline, edgeline, shoulder). 44 Lighting presence. After the mobile data collection started, SHRP 2, in coop- eration with FHWA, added two additional items to the previ- ous list: all Manual on Uniform Traffic Control Devices (MUTCD) signs and information about guardrails and bar- riers. Additional information is provided in other sections of this report. 2.4 Identification of Data resources Throughout the project, the research team focused on identify- ing and acquiring data from Tier 1 and Tier 2 data items from publicly available resources and SHRP 2 contacts at state and local transportation agencies. Additional data were also sought for supplemental data items. The intention was to include as much of the prioritized data items as possible in the RID for future safety research. Appendix A gives a detailed report of this effort. 2.5 Determining Capabilities of Mobile Data Collection Vendors In order to select a vendor to collect the mobile data, SHRP 2 completed the Roadway Measurement System Evaluation (Rodeo), which was conducted by a separate contracting team under Safety Project S03. Project S03 was part of a prequalification stage for the mobile data collection project. Ten vendors participated in the Rodeo. However, the Rodeo results were not sufficient for SHRP 2 to confidently develop a short list of vendors that would respond to a data collection request for proposals (RFP). To support SHRP 2 in this effort, the project S04A research team completed a task with the objective of further evaluat- ing the capabilities of the vendors who participated in the Rodeo. This was accomplished through documenting each
9 vendorâs ability to collect roadway geometric data and some selected inventory data features on two of the six Rodeo con- trol sites (6S and 7N). Seven out of the original 10 Rodeo vendors participated by completing three data collection runs for each of the two roadway segments identified. The seven data features collected for each roadway segment included roadway section (location/length), horizontal curve, grade, cross slope, lane width, paved shoulder width, and speed limit signs. The data submitted by each vendor were evaluated for accuracy and precision. The vendor evaluation results were presented to the SHRP 2 Expert Task Group (ETG) on Acqui- sition of Roadway Information at a meeting in Washington, D.C. The ETG members scored each vendor based on whether they were positive, neutral, or negative for each data element and the importance level of that data element. Possible scores ranged from -18 (worst performance) to +18 (best perfor- mance). The ETG members made the recommendation to qualify three of the seven vendors based on the data pre- sented, minimum accuracy requirements, and data item importance level. Details of this effort are presented in Appendix B. Based on the results of the evaluation, SHRP 2 issued a data collection RFP (Project S04B) to the qualified vendors and the ETG selected the contractor based on a com- bination of qualifications, past experience, and cost.