Alternative Technologies for Mitigating the Risk of Injuries and Deaths in Work Zones: Conduct of Research (2022)

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10 CHAPTER 2: Research Approach As described in Chapter 1, the research study seeks to fulfill the need for guidance on work zone intrusion mitigation technology usage. This goal was attained by identifying successful applications of existing and emerging technologies to mitigate work zone intrusions (referred to as work zone intrusion technologies, or WZITs henceforth), and developing a technology implementation guide and DSS to assist transportation agencies with selecting and implementing technologies to prevent work zone intrusions, and ultimately improve work zone safety. The stated research objectives were accomplished through completing the following five overarching activities (A1 – A5): A1. Literature review and readiness assessment of existing WZITs; A2. Determination of the state of practice of WZIT usage through a survey of industry; A3. Identification of successful practices through case study analysis of WZIT implementations; A4. Development of a guidance document for WZIT adoption, selection, and implementation; and A5. Prepare final research report. An objective comparison of available WZITs was conducted by performing a technology readiness assessment (TRA) of the technologies. A TRA is a standard process used to determine the maturity of an innovation (FHWA 2017). The TRA conducted will result in a standard 9-scale technology readiness level (TRL) for each technology application. Additional information about the TRA, including a description of each TRL, is provided in the FHWA TRL Guide (FHWA 2017). Figure 2.1 shows the logical interrelation between research activities A1 – A4 and the study output by utilizing TRLs within the research framework. These activities and the related research tasks are elaborated upon in subsequent subsections below. Figure 2.1. Overall research plan As can be seen in Figure 2.1, the TRLs that are assigned as an outcome of the literature review (Activity 1) will influence the decision about which technologies will be included in the survey (Activity 2) and case study selection (Activity 3), both of which will inform the development of the guidance document (Activity 4).

11 Each activity included one or more specific tasks needed to complete the activity. Table 2.1 provides a summary of the primary tasks (T1.1 – T4.3) involved in performing the activities (A1 – A4), along with the planned outputs from each activity. Activity A5 constitutes the preparation of the draft and final research reports. Detailed descriptions of each activity and task are provided in subsequent subsections below. Table 2.1. Summary of research activities and tasks Research Objectives Objective 1: Identification of successful applications of WZITs Objective 2: Development of a technology implementation guide for WZITs Research Activities A1: Literature review and technology assessment A2: Survey of industry A3: Document case studies A4: Develop guidance document Research Tasks T1.1: Conduct systematic literature review T1.2: Develop WZIT taxonomy T1.3*: Assess TRL for each WZIT technology use T2.1: Sample determination T2.2*: Survey design and distribution T2.3: Survey data collection and analysis T3.1*: Select case studies T3.2: Collect case study data and documentation T3.3: Develop case study conclusions and implications T4.1: Develop guidance document T4.2: Develop WZIT DSS T4.3*: Evaluate DSS and guidance document Research Outputs WZIT taxonomy and TRL assignments State of practice and adoption of WZIT Lessons learned from previous implementation WZIT guidance document * These tasks involve the participation of industry and the disadvantaged business enterprises (DBEs) involved in the study. 2.1 Literature Review of Application of Work Zone Intrusion Technology (Activity A1) Activity A1 involves a review of extant literature from academia, transportation agencies, and industry journals to establish the larger context for this research. Particular attention is given to previous studies that focus specifically on intrusion systems with safety applications for highway work zones, including those that involve vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), and vehicle-to-person (V2P) communication. The tactical objective of the literature review is to classify and assess the readiness levels of available technologies for work zone safety, which informed the downstream research activities. Fulfilling this objective is accomplished through three research tasks: (T1.1) a systematic literature review; (T1.2) development of a taxonomy for WZIT technology based on use case and technology type; and (T1.3) assessment of TRLs for each

12 type of technology for selected work zone applications. Each research task is described in detail below. 2.1.1 Conduct Systematic Literature Review (Task T1.1) A systematic literature review, as described by Siddaway (2014), is conducted to obtain an exhaustive list of current WZITs. This task is performed using the following steps: identification, eligibility assessment, and data extraction. The research team previously implemented a similar rigorous process to identify and assess WZITs (Nnaji et al. 2019; Louis et al. 2018). This previous experience provided the PIs with a foundational list of relevant keywords and a library of previously published literature on WZIT that is updated in the present study to include more recent advances in the field. Identification of relevant papers is performed by first creating search terms relevant to the WZIT domain. To do so, the research team accessed multiple research databases such as Transport Research International Documentation (TRID), Google Scholar, and American Society of Civil Engineers (ASCE) to select relevant peer-reviewed journal and conference papers, Federal and State reports, and available best practices/case studies. At this stage, the relevancy of each article is directly examined online based on its title, abstract, and keywords (where applicable), and used to screen the articles. The documents are then screened further based on information in headings, figures, tables, and conclusions. The selected articles then undergo a full- text eligibility assessment by the researchers based on specified inclusion/exclusion criteria. The following details about the technology implementations are extracted in preparation for the next research task of developing a WZIT taxonomy: technology used, application use case, year of implementation, results observed, and performance characteristics. As part of the literature review, the research team also reviewed highway construction incident cases archived in the National Institute for Occupational Safety and Health (NIOSH) Fatality Assessment and Control Evaluation (FACE) Program to identify opportunities for applying WZITs. The reports in the NIOSH FACE Program provide a detailed description of fatality incidents, their causes, involved parties, and potential solutions to prevent similar incidents in the future. The research team evaluated the five Ws (who, what, when, where, and why) of each highway work zone related incident reported in the FACE program using a review protocol. 2.1.2 Develop WZIT Taxonomy (Task T1.2) A taxonomy of current WZIT is required to enable a meta-analysis of its state of the art and practice at multiple levels. The taxonomy also enables the application of TRA to WZIT by permitting the assessment to be performed on broader classes of technologies and use cases rather than specific implementations of technology. For example, technologies may be categorized according to their sensor and/or actuator type, application use and environment (e.g., mobile operations), and other work zone, operation, or technology features. Primary taxonomy levels will typically be the technology type and application use. Secondary levels will commonly be such items as technology characteristics, capabilities, and documented implementation benefits and limitations. Using knowledge gained by the researchers from their prior research studies of WZIT, Table 2.2 shows an illustrative matrix developed based on the primary taxonomy levels of technology type and use case. The first column in the table provides the broader category of technology classification, the second column provides specific technologies within that classification, and

13 columns 3-5 indicate whether that technology can be used to detect an intrusion or imminent hazard based on the types of entities involved (vehicle, person, or infrastructure). The table cells are populated with examples of technology application based on previous research. The table is for illustrative purposes only and is not exhaustive; a comprehensive and detailed list of technologies and papers is created in the study. Table 2.2. Illustrative examples of WZIT and related technologies Technology Classification and Use (non-exhaustive) Specific Technology Employed (non-exhaustive) Application Use Cases Categories Vehicle-to- Vehicle (V2V) Vehicle-to- Infrastructure (V2I) Vehicle-to- Person (V2P) Perimeter monitoring and intrusion alert Radar, pneumatic tube, radio frequency, infrared --- Nnaji et al. (2018) Gambatese et al. (2017a) Computer vision and ranging Camera, lidar, radar Ijjina et al. (2019) Zhang et al. (2019) Zhu et al. (2016) Localization Global positioning system (GPS), ultra- wideband (UWB), Bluetooth low energy (BLE) Rashid et al. (2017) Luo et al. (2016) Louis et al. (2018) Automated identification RFID Wang et al. (2014) Lee et al. (2011) Chae and Yoshida (2010) 2.1.3 Assess TRL for Each Technology (Task T1.3) The maturity of each WZITs identified in Task T1.2 is systematically analyzed for its level of technology readiness for application to the specific use cases identified in Task T1.2. Towards this end, after the taxonomy and classification of the identified WZIT is performed, a hierarchical breakdown of the WZIT system is performed to identify its critical technology elements (CTEs), i.e., those elements of the technology needed to successfully meet a system operational threshold requirement. These CTEs are then be scored on the basis of their maturity (i.e., readiness for and applicability to the use cases) by a group of subject matter experts that include the research team and the industry experts. This scoring results in assigning a TRL to each WZIT based on the 9- point NASA scale (NASA 2009), which varies from TRL 1 to TRL 9 as shown in Table 2.3. The table also shows the corresponding “construction work zone equivalent” descriptions for each TRL as developed by the research team.

14 Table 2.3. Technology readiness levels TRL NASA TRL Descriptions (NASA 2009) NASA TRL Descriptions Adapted to Construction Work Zones 1 Basic principles observed and reported Basic principles observed and reported 2 Technology concept and/or application formulated Technology concept and/or application formulated 3 Analytical and experimental critical function and/or characteristic proof of concept Analytical and experimental critical function and/or characteristic proof of concept 4 Component and/or breadboard validation in laboratory environment Component and/or breadboard validation in laboratory environment 5 Component and/or breadboard validation in relevant environment Component and/or breadboard validation in a simulated, controlled construction environment 6 System/subsystem model or prototype demonstration in a relevant environment (ground or space) System/subsystem model or prototype demonstration in a simulated, controlled construction environment 7 System prototype demonstration in a space environment System prototype demonstration in an actual construction environment 8 Actual system completed and "flight qualified" through test and demonstration (ground or space) Actual system completed and "live work zone qualified" through test and demonstration 9 Actual system "flight proven" through successful mission operations Actual system "work zone proven" through successful actual construction operations The TRLs described above provide the basis for selecting technologies to include in the survey (TRL ≥ 6). Technologies with TRL 6 and above are selected for inclusion in the survey (Activity 2) because technologies with TRLs below 6 are considered in this research to still be in the development phase and thus unsuitable for deployment in the field. Furthermore, technologies with TRLs 8 and 9 will be deemed to be sufficiently advanced in the development cycle to be suitable for the case study analysis (Activity 3). The by-product of this process is the identification of nascent technologies (with TRL < 6) for which further work is required prior to field implementation. Categorization of each of the technologies based on TRL also enables the creation of a “readiness matrix” that depicts the grouping of the technologies according to their readiness for implementation, type, and application use case. For example, a matrix could be developed that groups together localization technologies with different TRLs (e.g., TRL < 6, TRL = 6-7, and TRL = 8-9). The matrix would reveal the general distribution of technologies based on their readiness for implementation in practice.

15 2.2 Survey Development and Deployment for Data Collection (Activity A2) The primary objective of Activity A2 is to generate quantitative information on the types of WZIT used by state DOTs and contractors, the perceived effectiveness of the technologies, and factors that influence successful implementation of WZIT. This information is collected using an online survey, and verified through case study interviews (in Activity 3). The outcomes of Activity A1 inform the development and content of the survey questionnaire. 2.2.1 Survey Sample Determination (Task T2.1) The successful adoption, implementation, and acceptance of a safety technology requires a combination of top-down and bottom-up approaches within an organization’s personnel hierarchy (Nnaji et al. 2019b; 2019c). Hence, it is critical to acquire information from different stakeholders involved in the decision to adopt and use a technology. Therefore, the study targeted DOTs, GCs, subcontractors (e.g., traffic control contractors), and WZIT manufacturers/researchers through purposive sampling. Targeting this breadth of stakeholders ensures that a holistic picture of the current state of WZIT integration is captured. Moreover, this approach generates critical insights required to enhance WZIT technology transfer. To this end, this task involved recruiting at least one DOT personnel from each state (n = 50) who has sufficient knowledge of work zone safety/traffic control to participate in the survey. The research team liaised with the National Cooperative Highway Research Program (NCHRP) project panel to identify subject matter experts within the state DOTs. To complement the input provided by DOT personnel, the research team also targeted at least 50 survey respondents in each subgroup (GCs, subcontractors, and traffic control device manufacturers/researchers). GCs, subcontractors, WZIT manufacturers/researchers vendors were contacted through in-state and national contacts at the Associated General Contractors (AGC) of Oregon, AGC Alabama, AGC of America, Asphalt Pavement Association of Oregon (APAO), American Traffic Safety Services Association (ATSSA), American Road and Transportation Builders Association (ARTBA), and contacts amassed by the research team from previous WZIT-related studies (Gambatese et al. 2017a; Louis et al. 2018; Eseonu et al. 2018). The researchers ensured that the survey sample consisted of representatives located in all regions of the country in order to prevent regional biases in the results. The researchers believe that the aggregate sample of participants from the DOTs and industry as described above provide both a comprehensive and expert perspective of WZITs and their application in current practice. 2.2.2 Survey Design and Distribution (Task T2.2) Task T2.2 involved the design and distribution of an online survey questionnaire to collect quantifiable data on the use of WZIT. It is expected that industry knowledge and use of WZITs has changed since previous studies were conducted. The data sought in the present study provides new data to complement and update that which has been reported from previous studies. As mentioned previously, the survey sample population includes DOT personnel, GCs (field and management employees), subcontractors, and WZIT manufacturers/researchers. Given the nature of the survey content and the types of organizations in the survey sample, only one survey questionnaire is developed and deployed. The content and format of the survey is developed in

16 consultation with the NCHRP Project Panel. The survey contains multiple sections that collect different information from the respondents. A copy of the survey questionnaire is provided in the Appendix. The survey content is as follows: • Section 1 – Demographic information such as DOT/company size and location, company type and services offered, and the respondents’ level of experience, job title, and level of involvement in technology adoption decision-making. This information is used to normalize the data during analysis, thereby ensuring external validity. • Section 2 – The types of technologies currently used within the respondent’s organization and when they started using the technologies. Respondents are also asked about those technologies that they plan to use soon, and those they have no plans to adopt and use. For those technologies that they use, the respondents are asked to provide information on how they use the technologies. • Section 3 – Respondents are asked to rate the effectiveness of specific WZITs in preventing intrusions that typically occur in a work zone. • Section 4 – Participants are asked to assess, in terms of extent of impact and significance, the factors identified in Activity 1 (technology, application use case, and environment factors) that influence the successful implementation of WZIT, and provide strategies for overcoming possible barriers and limitations. At the end of the online survey, participants are given the option to participate in a follow-up interview (part of Activity 3). Those participants who agree to also participate in the interview are asked to provide basic contact information (name, email address, willingness to share case study(s) on WZIT implementation) in a linked-out survey to preserve anonymity. This process has been used successfully in previous projects to identify participants who are willing to provide critical qualitative insight (Gambatese et al. 2017a). Moreover, this process also enables developing a pool of participants willing to provide useful case studies (Gambatese et al. 2017b) – a key step/requirement in Activity 3. Prior to survey distribution, this task involved pilot testing the survey using insight from the subject matter experts as well as the NCHRP Project Panel. The reviewers are asked to provide feedback on how the survey questionnaire can be improved in terms of structure, format, order of questions, question clarity, terminology, etc. The research team then modified the survey questionnaire based on the feedback received during the pilot test. Subsequently, the research team submitted the survey questionnaire and protocol for Institutional Review Board approval for research involving human subjects. The survey questionnaire is put online using the Qualtrics online surveying tool. Links to the online survey questionnaire are then distributed to the target sample using personalized email invitations sent by the researchers. The invitations provide sufficient information to potential participants to ensure that only participants willing to provide useful information will proceed with the survey. The email originated from an OSU email address and included information that shows the study is funded by NCHRP. A link to the survey is embedded in the online email hosted by Qualtrics. Non-responders, i.e., those who do not expressly decline to participate in the study, receive a personalized email reminder after one, two, and four week(s). It is expected that this process helped drive up the response rate from the targeted stakeholders.

17 2.2.3 Survey Data Management and Analysis (Task T2.3) After receipt of the survey responses, the research team performed initial descriptive analyses of the responses within Qualtrics to determine if the appropriate sample quotas have been met. Subsequently, the research team exported the data from Qualtrics for further analysis and data management. As part of the data management process, the research team evaluated each response to determine the quality of the response. For instance, incomplete responses (i.e., those with less than 70% of the questions answered), straight liners (i.e., those respondents who selected all the same answers), and speeders (those responses completed in two or more standard deviations less than the mean completion time) are eliminated from the data set. This data management process ensures that only quality responses are included in the analysis. Following the quality check, the research team analyzed the data using appropriate statistical tools, including descriptive analysis (e.g., mean, median, mode, standard deviation, etc.), t-tests, and analysis of variance. The specific statistical tool selected depended on the nature and amount of data available, plus the research question being asked. 2.3 Identification and Investigation of Successful Case Studies (Activity A3) The third activity in the research plan (Activity A3) constituted investigating and documenting existing case studies of successful implementation of WZIT that mitigate the risk of vehicle intrusions into work zones and equipment-human contact. This activity provides a closer and more holistic study of WZIT implementation within its real-life context. In addition, this activity hones the knowledge acquired from Activities 1 (state of the art of WZIT) and 2 (state of practice of WZIT) towards actionable insight that will guide successful implementation (Activity 4, guidance document development). Four to six case studies are selected that target technologies with TRLs equal to 8 and 9 in order to provide a broader range of guidance insights for industry in the guidance document. This activity involves the following tasks: (T3.1) selection of case studies; (T3.2) case study data collection and documentation; and (T3.3) development of case study conclusions and implications. 2.3.1 Selection of Case Studies (Task T3.1) Eligible technologies that are supported by the TRA in Activity 1 and further supported by the responses from industry through the survey responses in Activity 2 are targeted for further investigation. In addition, priority is given to technologies that are included in the Highway Safety Manual (HSM) (AASHTO 2010). Thirteen potential studies were identified and pursued to gauge interest of the implementer in participation in the study, and six were selected for documentation and analysis. The researchers consulted with the NCHRP Project Panel to confirm the specific case studies to include from those preliminarily identified. 2.3.2 Case Study Data Collection and Documentation (Task T3.2) The process for documenting each case study involved gathering the following data: technology characteristics, application and usage details, implementation plan, and user evaluation of WZIT effectiveness. Other details of interest, such as the typical environmental conditions of usage,

18 frequency of usage, applicable project characteristics, and other pertinent information specific to the case study under investigation, are also collected. These data are collected through a multi- modal data gathering effort consisting of the following sources and methods: semi-structured interviews of DOT and contractor personnel, review of manufacturer documentation and archival literature, and observation of WZIT implementation. To conduct the interviews, the researchers utilized a set of standard questions devised to capture the desired information. 2.3.3 Development of Case Study Conclusions and Implications (Task T3.3) The final task from the case study analysis (T3.3) enables the identification of lessons to be learned from successful case implementations of WZIT that can inform best practices and guidelines development for Activity 4. More specifically, the data gathered about the specific case studies provide insight into guidelines that are applicable to a particular WZIT implementation, as well as across multiple classes of technologies and applications. The following methods are utilized to draw both specific conclusions about the individual case studies and more generalized conclusions about all case studies and used for the development of guidance document: data reduction; conclusion drawing and verification; and narrative analysis. The researchers utilized the expertise of the subject matter experts to assist with this task. 2.4 Development of Industry Guidance (Activity A4) Development of the WZIT guidance document synthesized the information gained from the study into actionable insights and guidelines that can be implemented in work zones by DOTs and the industry. Towards this end, the research team also developed a decision-making tool that accompanies the guidance document itself. Both of these outputs are evaluated using an industry focus group for iterative development. 2.4.1 Development of Guidance Document (Task T4.1) The study involved the development of best practice guidelines to ensure a uniform process and method that, when executed effectively, leads to enhanced application of intrusion technologies for improving safety in highway work zones. The primary outputs from Activities 1, 2, and 3 are used to inform the content of the guidance document. The guideline includes an overview of WZITs, case studies of actual use, and effective WZIT implementation strategies that could be integrated into the updated traffic control plan in the new HSM. A DSS (described below in Task T4.2) is also included to actively guide users through the decision process of selecting and implementing a WZITs. The standalone guide contains the following content: • Section 1 – Guide Overview o This section provides an introduction to the guide, types of problems addressed, and insight on how to use the guide. • Section 2 – Safety in Work Zones o An overview of safety concerns associated with work zone operations. The five Ws – who (involved party), what (types of incidents), when (conditions), where (location in work zone), and why (causes) – of work zone incidents are provided. • Section 3 – Work Zone Safety Technologies

19 o Technologies developed to enhance safety in work zones are described in detail. A catalog of WZITs is provided, highlighting their potential applications, effectiveness, and maturity. o Technology readiness matrix displaying the present applicability and maturity of the WZITs for application and use. • Section 4 – Using the DSS o An overview of the process for applying the developed DSS is provided. For brevity, a link is provided to a web page housing the tool and a detailed description of the application process. • References 2.4.2 Multi-Criteria DSS (Task T4.2) Task T4.2 is the development of a DSS to select and apply WZITs using information on project characteristics from the new Highway System Manual, and findings from study Activities 1 to 3. The DSS relies on a multi-method framework to arrive at a reliable technology adoption and implementation decision. The system allows users to input desired criteria about the site conditions, work operations, and WZIT specifications, and then provides a list of WZITs that are available and applicable to satisfy the criteria. The tool is created using JavaScript and Google Webapps, in order to disseminate the research results widely through the browser to any interested transportation personnel. The tool uses information on technology characteristics (cost, effectiveness, durability, trigger mechanism, alert type, etc.), environmental conditions (day/night, weather/season, etc.), project specific information (type of work zone, speed limit of work zone, traffic control configuration, frequency of specific incidents, etc.), and organization readiness insight (technology budget, worker openness to using technology, etc.). All components and variables of the decision-making framework are clearly identified, defined, characterized, and interpreted. The framework is verified using feedback from the subject matter experts. 2.4.3 Guide and DSS Evaluation (Task T4.3) This task involves utilizing a group of subject matter experts to support identifying guidance to assist implementation in practice. The input received from the subject matter experts, along with the results of the previous research tasks, ensures the validity of the guidance document and DSS prior to its review by the NCHRP Project Panel. The information received is recorded and analyzed to better understand the effectiveness of the guidance document and DSS. The assessment and feedback received from participants equips the research team with the knowledge needed to modify and improve the recommended best practices and implementation guide. Subsequently, the NCHRP Project Panel were asked to rate the final products for ease of use, practicality (accuracy and consistency), engagement, and effectiveness (sufficient breadth and depth).