Use of Smart Work Zone Technologies for Improving Work Zone Safety (2022)

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46 Use of Smart Work Zone Technologies for Improving Work Zone Safety (Map created with mapchart.net ©) (Map created with mapchart.net ©) Figure 35. Map showing implementation status for traveler information systems by DOTs. Figure 36. Map showing implementation status for QWSs by DOTs.

Survey Results 47   (Map created with mapchart.net ©) (Map created with mapchart.net ©) Figure 37. Map showing implementation status for work zone data collection technologies by DOTs. Figure 38. Map showing implementation status for work zone location technologies by DOTs.

48 Use of Smart Work Zone Technologies for Improving Work Zone Safety • One DOT attempts to disseminate information using both Internet-enabled methods and older technologies such as radio. • A responding DOT used a QWS once. Frequency of Use of Smart Work Zone Technologies by DOTs In Question 2, DOTs were asked to rank their implemented smart work zone technologies based on frequency of use, with a ranking of one indicating the most frequently used smart work zone technology. As shown by the average rankings in Table 8, the most frequently used smart work zone technologies are traveler information systems, queue warning, and dynamic (variable) speed limit systems, while notification of construction equipment entering or exiting and work zone intrusion alarms are the least frequently used smart work zone technologies. As indicated by the map showing the most frequently used smart work zone technology by DOT in Figure 39, QWSs are more frequently used by some North Central and Midwestern DOTs. Q2. Based on your response to the previous question, the list of smart work zone technologies that your agency has already implemented is shown below. Please rank these technologies based on how frequently your agency uses them (1 = most frequently used technology, 2 = second most frequently used technology, etc.). In your rankings, please use each number only once. Technology Relative Rank of Technology Average Ranking Standard Deviation Lowest Ranking Highest Ranking Number of Responses Traveler Information Systems 1 1.49 0.93 1 4 37 Queue Warning 2 2.16 1.13 1 6 31 Dynamic (Variable) Speed Limit 3 2.17 0.94 1 4 12 Other 4 2.25 1.50 1 4 4 Work Zone Location Technologies 5 2.92 1.16 1 5 12 Work Zone Data Collection Technologies 6 3.06 1.39 1 6 17 Dynamic Lane Merge 7 3.38 1.19 2 5 13 Notification of Construction Equipment Entering/ Exiting 8 3.56 1.67 1 5 9 Work Zone Intrusion Alarm 9 3.67 1.15 3 5 3 NOTES: Sort order = average ranking (low to high); cell shading based on increments of 1; total number of respondents = 51. Table 8. Survey results for frequency of use of smart work zone technologies.

Survey Results 49   Additional details on frequency of use from survey comments include the following: • One DOT noted that it usually uses queue warning and dynamic lane-merge systems together. • One DOT recently implemented construction equipment entering/exiting systems and work zone location technologies and is working toward making them standard on all Interstate projects. • One DOT does not plan to use work zone intrusion alarms in the future because of poor results obtained previously. To assess potential impacts of geography on the frequency use of smart work zone technolo- gies, the DOTs were grouped into climate regions from the National Oceanic and Atmospheric Administration (NOAA) as shown in Figure 40. For purposes of analysis, the Alaska DOT was assigned to the Northwest region, the Hawaii DOT was assigned to the West region, and the District DOT was assigned to the Northeast region. Table 9 shows the survey results for the rankings based on frequency of use for traveler infor- mation systems, queue warning, and dynamic (variable) speed limit systems. Some general trends can be observed in Table 9. For example, traveler information systems are used more frequently in the Northeast, Northwest, South, West, and West North Central regions and less frequently in the East North Central region. Queue warning systems are used more frequently in the Central, Southwest, and West North Central regions, while dynamic (variable) speed limit systems are used more often in the Southeast and Southwest regions. Additional statistics for the frequency of use of all types of smart work zone technologies by climate region are provided in Appendix G. (Map created with mapchart.net ©) Figure 39. Map showing most frequently used smart work zone technology by DOT.

50 Use of Smart Work Zone Technologies for Improving Work Zone Safety Source: NOAA n.d. Region Tr av el er In fo rm at io n Sy st em s (A ve ra ge R an ki ng )* Tr av el er In fo rm at io n Sy st em s (R el at iv e R an ki ng fo r Fr eq ue nc y of U se b y C lim at e R eg io n) Q ue ue W ar ni ng (A ve ra ge R an ki ng )* Q ue ue W ar ni ng (R el at iv e R an ki ng fo r F re qu en cy o f U se by C lim at e R eg io n) D yn am ic (V ar ia bl e) S pe ed Li m it (A ve ra ge R an ki ng )* D yn am ic (V ar ia bl e) S pe ed Li m it (R el at iv e R an ki ng fo r Fr eq ue nc y of U se b y C lim at e R eg io n) All 1.49 - 2.16 - 2.17 - Central 1.43 4 1.29 2 2.57 4 East North Central 2.75 7 1.75 4 - - Northeast 1.14 2 2.33 6 2.50 3 Northwest 1.00 1 2.00 5 - - South 1.17 3 2.33 6 - - Southeast 1.60 5 3.67 8 1.50 2 Southwest 1.67 6 1.00 1 1.00 1 West 1.00 1 3.00 7 3.00 5 West North Central 1.00 1 1.33 3 3.00 5 * 1 = most frequently used technology, 2 = second most frequently used technology, and so forth. Figure 40. Climate regions of the continental United States. Table 9. Survey results for average ranking based on frequency of use of traveler information systems, queue warning, and dynamic (variable) speed limit by climate region.

Survey Results 51   Use of Multiple Smart Work Zone Technologies by DOTs Question 4 of the survey sought information regarding how frequently DOTs use combina- tions of smart work zone technologies on the same project. As shown in Table 10, approximately 80% of DOTs use multiple technologies on the same project to some extent. Additional details provided in the comments include the following: • One DOT indicated that it is starting its second project that incorporates multiple smart work zone technologies. • One DOT typically only uses multiple technologies on projects that involve long corridors and multiple contracts. • One DOT developed specifications that allow project designers to specify queue warning, dynamic lane merge, and travel time information systems. Performance of Smart Work Zone Technologies DOT Performance Ratings and Evaluation Studies Respondents were asked to rate the performance of smart work zone technologies on a scale of one (poor) to five (outstanding), and the results are shown in Table 11. Traveler information systems, queue warning, and dynamic late merge received the highest average ratings, while notification of construction equipment entering or exiting and work zone intrusion alarm were scored the lowest by survey respondents. There is a high degree of variability in the ratings, as the scores ranged from one to five, suggesting a wide range of DOT experiences with smart work zone technologies. Dynamic lane-merge systems have the highest standard deviation, indi- cating the most variability in the ratings. Additional details on performance provided through comments include the following: • One DOT noted that it has been using QWSs for approximately 1 year and is resolving some minor issues with the systems. • One DOT is reducing its use of dynamic (variable) speed limits on permanent devices. Q4. How frequently does your agency use multiple smart work zone technologies in conjunction with each other on the same project? Frequency Response Always 4% Almost Always 14% Sometimes 47% Rarely 20% Never 16% No Response 0% NOTES: Frequency (descending); cell shading based on increments of 25%; total number of respondents = 51. Table 10. Survey results for frequency of use of multiple smart work zone technologies on the same project.

52 Use of Smart Work Zone Technologies for Improving Work Zone Safety • One DOT has obtained significant safety and capacity improvements through combined implementation of dynamic lane merge and QWSs at long-term freeway closures. • One DOT recently implemented work zone location technologies and is encountering some challenges with how to broadcast the information. An analysis of average DOT performance rating by climate region was performed, and the findings for dynamic (variable) speed limit, queue warning, and traveler information systems are shown in Figure 41. The results indicate that dynamic (variable) speed limits are rated higher by DOTs in the Southwest region and lower by DOTs in the Central and West North Central regions. DOT performance ratings for QWSs are higher than the overall average in the Northeast and Southwest regions and lower than the overall average in the West and Northwest regions. Finally, DOTs in the Northeast, West, and West Central regions perceive better per- formance with traveler information systems, while DOTs in the East North Central, Northwest, and Southwest regions rate traveler information systems lower than other DOTs. Additional statistics for the DOT performance ratings of the smart work zone technologies by climate region are provided in Appendix H. The results for Question 16, shown in Table 12, demonstrate that only 12% of DOTs have completed performance evaluations or economic studies for smart work zone technologies. Two DOTs submitted evaluation studies, while Tennessee submitted a description for a planned study on work zone intrusion alarms. One DOT indicated in the comments that it has a research study to evaluate its smart work zones in progress. Q3. On a scale of 1 to 5 (1 = Poor, 5 = Outstanding, 0 = No opinion), how would you rate the performance of each of the following smart work zone technologies in your agency’s jurisdiction? Technology Average Rating Standard Deviation Lowest Rating Highest Rating Number of Ratings Total Responses (Including No Opinion) Traveler Information Systems 4.00 0.78 2 5 40 40 Queue Warning 3.87 0.96 1 5 31 31 Dynamic Lane Merge 3.79 1.12 1 5 14 14 Other 3.75 0.96 3 5 4 4 Dynamic (Variable) Speed Limit 3.33 0.49 3 4 12 12 Work Zone Location Technologies 3.50 0.97 1 4 10 11 Work Zone Data Collection Technologies 3.12 1.05 1 5 17 17 Notification of Construction Equipment Entering/Exiting 2.71 0.95 1 4 7 7 Work Zone Intrusion Alarm 2.50 0.71 2 3 2 2 NOTES: Sort order = average rating (high to low); cell shading based on increments of 1; total number of respondents = 51. Table 11. Survey results for performance ratings of smart work zone technologies.

Survey Results 53   DOT Performance Measures for Smart Work Zone Technologies Questions 12 through 15 of the survey collected information regarding the use of performance measures for smart work zone technologies. As shown in Figure 42, crash statistics are the most commonly employed safety performance measure for assessing safety impacts of smart work zone technologies. In addition, approximately one-quarter of DOTs use worker injury statistics, surrogate measures, and work zone inspection results. Two DOTs noted in the comments that they are not yet ready to set and use performance measures for smart work zone technologies. Queue length is the most frequently used performance measure used by DOTs to assess the operational impacts of smart work zone technologies (Figure 43). At least one-third of DOTs also employ delay, work zone incidents, speed, and travel time for operational evaluations of Q16. Has your agency completed any studies to evaluate the effectiveness and/or return on investment of smart work zone technologies? Yes 12% No 86% No Response 2% NOTES: Total number of respondents = 51. Figure 41. Survey results for average DOT performance rating of implemented smart work zone technology for dynamic (variable) speed limit, queue warning, and traveler information systems by climate region (1 = Poor, 5 = Outstanding). Table 12. Survey results for completion of evaluation or economic studies for smart work zone technologies.

54 Use of Smart Work Zone Technologies for Improving Work Zone Safety smart work zone technologies. One responding DOT indicated in the comments that it collects monthly performance metrics for a subset of high priority projects that may or may not include smart work zone technologies. As shown in Table 13, only 31% of DOTs automatically collect data for work zone perfor- mance measures and store the data in a central location. In the comments, two DOTs indicated that they are working toward implementation of this practice. Another DOT asks for data avail- ability in its specications. Question 15 sought information regarding ways that DOTs use the performance measures that are collected for smart work zone technologies. As shown in Table 14, the identication and Total number of respondents = 51; ordered by Always + Almost Always—high to low. Figure 42. Survey results for frequency of use of performance measures to assess safety impacts of smart work zone technologies.

Survey Results 55   Total number of respondents = 51; ordered by Always + Almost Always—high to low. Figure 43. Survey results for frequency of use of performance measures to assess operational impacts of smart work zone technologies. Q14. Does your agency automatically collect data for work zone performance measures and store the data in a central location (for example, collecting ATMS data through a Traffic Management Center)? Yes 31% No 63% No Response 6% NOTES: Total number of respondents = 51. Table 13. Survey results for automatic collection and storage of data for work zone performance measures.

56 Use of Smart Work Zone Technologies for Improving Work Zone Safety mitigation of project-level concerns is the most common application of performance measures for smart work zone technologies. At least one-third of DOTs also use measures to evaluate the performance of smart work zone technologies, improve work zone policy and procedures, or provide support for continued implementation and expansion of smart work zone technologies. One DOT stated in the comments that it has not been able to apply countermeasures because of staffing and time constraints, while another DOT is in the process of determining how it will use collected data. Components for Smart Work Zone Technologies DOT Methods for Disseminating Traveler Information Question 5 of the survey asked respondents about the frequency of use for different methods to communicate information regarding work zones to travelers. As shown in Table 15, CMSs are most frequently used to disseminate traveler information. The following methods are always or almost always used by at least two-thirds of DOTs: CMSs, print or broadcast media, social media, 511 systems, and websites. The least frequently used methods include text messages, real-time highway advisory radio, audible or visual alarms, and connected vehicle technologies. Two DOTs indicated that implementation of traveler information systems varies by geographic location. DOT Detection Components for Smart Work Zone Technologies In Question 10, respondents were asked about frequency of use of detection components to collect information for smart work zone technologies. As shown in Table 16, video cameras and traffic sensors are the most frequently used components and are each implemented always or almost always by 38% of DOTs. Approximately two-thirds of DOTs are using crowdsourcing data to collect information for smart work zone technologies to some extent. Bluetooth/Wi-Fi sensors, environmental sensors, and RFID are used less frequently than the other components. In the comments, one DOT indicated that it operates work zone cameras for detection of work zone intrusions. One DOT recently implemented crowdsourcing data, while another DOT plans to develop the use of crowdsourcing data in the future. Q15. How does your agency use the performance measures that are collected for smart work zone technologies? Please select all that apply. Application Response Identify and address project-level concerns 47% Evaluate performance of smart work zone technologies 43% Improve agency work zone policy and procedures 41% Provide support for continued use and expansion of smart work zone technologies 37% No response 27% Other 10% Performance-based incentives for the contractor 6% NOTES: Sort order = response (high to low); cell shading based on increments of 25%; total number of respondents = 51. Table 14. Survey results for application of performance measures that are collected for smart work zone technologies.

Survey Results 57   Q5. How frequently does your agency use each of the following methods to communicate information regarding work zones to travelers? Method Always Almost Always Sometimes Rarely Never No Response Changeable Message Signs (CMSs) 35% 51% 14% 0% 0% 0% Print or Broadcast Media 14% 59% 24% 2% 0% 2% Social Media 24% 49% 20% 6% 0% 2% 511 Systems 55% 14% 4% 4% 20% 4% Websites 35% 33% 27% 4% 0% 0% Smartphone Applications 18% 20% 27% 20% 12% 4% Static Signs with Dynamic Features 14% 20% 24% 18% 20% 6% Remotely Activated Traffic Control Devices 2% 12% 41% 20% 20% 6% Text Messages 0% 12% 24% 31% 31% 2% Real-Time Highway Advisory Radio (HAR) 4% 8% 20% 41% 24% 4% Audible or Visual Alarms 6% 2% 18% 25% 45% 4% Connected Vehicle Technologies 0% 4% 16% 18% 61% 2% Other 0% 0% 2% 0% 2% 96% NOTES: Sort order = Always + Almost Always (high to low); cell shading based on increments of 25%; total number of respondents = 51. Table 15. Survey results for frequency of use of methods to convey traveler information. Q6. How frequently does your agency use each of the following detection components to collect information for smart work zone technologies? Detection Component Always AlmostAlways Sometimes Rarely Never No Response Video Cameras 14% 24% 35% 12% 12% 4% Traffic Sensors 16% 22% 33% 12% 14% 4% Crowdsourcing Data 2% 22% 20% 22% 25% 10% Social Media 10% 10% 31% 20% 24% 6% Probe Vehicles 4% 12% 16% 22% 39% 8% Bluetooth/Wi-Fi Sensors 0% 4% 45% 18% 25% 8% Environmental Sensors 2% 0% 10% 27% 51% 10% Radio Frequency Identification (RFID) 0% 0% 12% 27% 49% 12% Other 0% 0% 2% 0% 2% 96% NOTES: Sort order = Always + Almost Always (high to low); cell shading based on 25% increments; total number of respondents = 51. Table 16. Survey results for frequency of use of detection components for smart work zone technologies.

58 Use of Smart Work Zone Technologies for Improving Work Zone Safety DOT Communication Components for Smart Work Zone Technologies Question 7 of the survey sought information regarding the frequency of use of various com- munication components for smart work zone technologies, and the results are shown in Table 17. Cellular telephone and wireless ethernet are the most commonly used communication compo- nents and are always or almost always employed by at least one-quarter of DOTs. Based on the “rarely” and “never” responses, optical, radio frequencies, hardwired cable, and satellite are the least frequently implemented communication components. In the comments, one DOT noted that it does not specify the type of connection required. One DOT indicated that it has a new ATM system that uses its fiber network. DOT Use of Smart Components on Existing Non-Smart Equipment Question 9 asked respondents how often they install smart components on existing non- smart equipment, such as adding smart arrow boards or smart cones at the beginning and end of the work zone. As shown in Table 18, only 37% of respondents install smart components on non-smart equipment with a frequency of always, almost always, or sometimes. Over one- quarter of DOTs do not apply this practice. Two DOTs indicated in the comments that they would like to implement this process in the future. One DOT is preparing a smart work zone request for proposal (RFP) and plans to have a vendor to provide these devices in the near future. DOT Implementation Considerations for Smart Work Zone Technologies Factors in the Selection of Smart Work Zone Technologies by DOTs In Question 8, respondents were asked how frequently various factors were considered when selecting which types of smart work zone technologies to implement. The results, shown in Table 19, show that the factors most commonly considered are traffic volumes, type of work, duration and length of the work zone, and existing traffic or safety issues. Traffic volumes and type of work are always or almost always considered by 84% of DOTs. The following factors are Q7. How frequently does your agency use each of the following communication components for smart work zone technologies? Communication Component Always Almost Always Sometimes Rarely Never No Response Cellular Telephone 12% 25% 35% 4% 18% 6% Wireless Ethernet 8% 20% 24% 8% 29% 12% Bluetooth 4% 8% 43% 16% 22% 8% Optical 2% 4% 8% 25% 49% 12% Radio Frequencies 0% 6% 25% 27% 29% 12% Hardwired Cable 0% 4% 20% 27% 37% 12% Satellite 0% 2% 4% 20% 63% 12% Other 0% 0% 0% 0% 4% 96% NOTES: Sort order = Always + Almost Always (high to low); cell shading based on 25% increments; total number of respondents = 51. Table 17. Survey results for frequency of use of communication components for smart work zone technologies.

Q9. When implementing smart work zone technologies, how frequently does your agency install smart components on existing non-smart equipment (for example, adding smart arrow boards or smart cones at the beginning and end of the work zone)? Frequency Response Always 4% Almost Always 0% Sometimes 33% Rarely 29% Never 27% No Response 6% NOTES: Sort order = frequency (descending); cell shading based on 25% increments; total number of respondents = 51. Q8. How often does your agency consider the following factors when selecting which types of smart work zone technologies to implement? Factor Always AlmostAlways Sometimes Rarely Never No Response Traffic Volumes 53% 31% 2% 0% 10% 4% Type of Work 43% 41% 2% 2% 10% 2% Duration and Length of Work Zone 43% 37% 6% 0% 10% 4% Existing Traffic or Safety Issues 51% 27% 8% 0% 10% 4% Work Zone Configuration 31% 35% 12% 4% 10% 8% Time of Day 27% 31% 14% 10% 12% 6% Cost 29% 29% 25% 4% 8% 4% Past Experience 35% 24% 27% 0% 10% 4% Proximity of Workers to Traffic 24% 31% 18% 10% 12% 6% Urban or Rural Jurisdiction 20% 31% 24% 2% 18% 6% Availability of Alternate Routes 20% 29% 24% 10% 14% 4% Commercial Motor Vehicles (CMVs) 12% 37% 25% 8% 12% 6% Public Reaction 14% 22% 37% 10% 14% 4% Weather Conditions 12% 20% 24% 20% 22% 4% Connected and Autonomous Vehicles 2% 4% 14% 18% 57% 6% Other 0% 0% 0% 0% 6% 94% NOTES: Sort order = Always + Almost Always (high to low); cell shading based on 25% increments; total number of respondents = 51. Table 18. Survey results for use of smart components on existing non-smart equipment. Table 19. Survey results for factors influencing selection of smart work zone technologies.

60 Use of Smart Work Zone Technologies for Improving Work Zone Safety always or almost always considered by at least half of the DOTs: traffic volumes, type of work, duration and length of work zone, existing traffic or safety issues, work zone configuration, time of day, cost, past experience, proximity of workers to traffic, and urban or rural jurisdiction. These results show that DOTs take a wide range of considerations into account when choosing smart work zone technologies. At the other end of the spectrum, less than one-third of DOTs always or almost always consider weather conditions and CAVs, and 57% of DOTs never take CAVs into account when selecting smart work zone technologies. DOT Implementation Challenges for Smart Work Zone Technologies Survey results for Question 10 regarding concerns that can hinder implementation of smart work zone technologies are shown in Table 20. Funding constraints and staffing shortages are the most reported obstacle to implementing smart work zone technologies as almost two-thirds Q10. How strongly do you agree or disagree that the following concerns have hindered your agency’s efforts to implement smart work zone technologies? Concern Strongly Agree Somewhat Agree Neither Agree nor Disagree Somewhat Disagree Strongly Disagree No Response Funding Constraints 24% 41% 18% 8% 6% 4% Agency Understaffed 22% 41% 24% 8% 2% 4% Contractor Availability/Expertise 8% 49% 29% 8% 4% 2% Time to Research and/or Implement 20% 35% 25% 8% 6% 6% Proper Expertise to Design or Review 6% 47% 25% 12% 2% 8% Lack of Perceived Need 8% 43% 25% 16% 4% 4% Technology Issues 14% 35% 18% 22% 6% 6% Contracting Considerations 10% 39% 33% 6% 8% 4% Data Availability 4% 39% 31% 6% 12% 8% Public Education 4% 27% 43% 14% 6% 6% Network Connectivity Issues 10% 22% 37% 20% 6% 6% Lack of Agency Buy- In 4% 24% 41% 20% 8% 4% Safety Impacts 8% 14% 31% 27% 14% 6% Operational Impacts 4% 18% 37% 29% 6% 6% Liability Issues 4% 10% 51% 20% 12% 4% Climate 0% 12% 45% 16% 22% 6% Other 0% 0% 4% 0% 0% 96% NOTES: Sort order = Strongly Agree + Somewhat Agree (high to low); cell shading based on 25% increments; total number of respondents = 51. Table 20. Survey results for implementation challenges for smart work zone technologies.

Survey Results 61   of DOTs strongly or somewhat agreed that those factors hinder efforts. Other challenges noted by the majority of DOTs include contractor availability and expertise, time to research and implement, proper expertise to design or review, and lack of perceived need. Another key finding is that liability issues and climate do not appear to be concerns, as less than 20% of respondents strongly or somewhat agree that these factors curb the use of smart work zone technologies at their DOT. Less than one-third of respondents believe that lack of agency buy-in limits their efforts to apply smart work zone technologies. DOT Resources for Smart Work Zone Technologies DOTs were asked about which types of resources they have developed to support their imple- mentation of smart work zone technologies. As shown in Table 21, contract special provisions are the only resource developed by a majority of DOTs. Specifications, guidelines, and concept of operations have been prepared by at least one-third of DOTs. Standard drawings, selection methodology or tool, and public outreach materials are the least commonly developed resources for smart work zone technologies. Other Survey Feedback from DOTs Questions 17 and 18 concluded the survey by inquiring into DOTs’ interest in participating in a case example and asking for any other general feedback. As shown in Table 22, 31% of DOTs indicated that they would be interested in participating in a case example. DOTs provided Q11. Which of the following resources has your agency developed to support implementation of smart work zone technologies? Please select all that apply. Resources Response Contract special provisions 55% Specifications 47% Guidelines 37% Concept of operations 33% Deployment plans 31% No response 27% Standard drawings 27% Selection methodology or tool 25% Public outreach materials 18% Other 18% NOTES: Sort order = Response (high to low); cell shading based on 25% increments; total number of respondents = 51. Table 21. Survey results for development of resources to support implementation of smart work zone technologies.

62 Use of Smart Work Zone Technologies for Improving Work Zone Safety information regarding projects for possible case examples. Open feedback from DOTs can be found in Appendix C, and some notable comments are listed as follows. • One DOT noted that the DOT is striving to develop boilerplate implementation strategies for smart work zones commensurate with project complexity. • One DOT found that limited staffing and equipment availability hinders efforts to implement smart work zone technologies. • One DOT does not have sufficient data to support the measure of effectiveness of smart work zone technologies. • One DOT is working to further advance implementation and performance measurement of smart work zone technologies. Summary of Key Survey Findings Key findings from the survey are summarized as follows. • The level of deployment of smart work zone technologies varies between DOTs, and, in some cases, between different regions of a given DOT. • Traveler information systems, which 78% of DOTs have implemented, are the most frequently used smart work zone technology. A majority of DOTs are also deploying QWSs. Only 18% and 6% of DOTs have implemented systems for notification of construction equipment entering or exiting and work zone intrusion alarms, respectively. • Other types of smart work zone technologies that DOTs have deployed include a website to provide information about lane closures, dynamic ramp meter with portable traffic signal, automated speed enforcement, and a downstream speed-notification system. • Analysis of the types of smart work zone technologies used by DOTs shows that there are some tendencies regarding geographic distribution by climate region of the United States. For example, the use of QWSs and work zone data collection technologies is more prevalent in the Midwestern, North Central, and South Central DOTs. • There appears to be significant interest by DOTs in work zone location technologies, as 51% of DOTs plan to implement these systems in the future. • Approximately 80% of DOTs use multiple technologies on the same project to some extent. • Traveler information systems, queue warning, and dynamic lane merge received the highest DOT performance ratings for smart work zone technologies, while notification of construction equipment entering or exiting and work zone intrusion alarms received the lowest performance Q17. The synthesis study will also include case examples demonstrating agency practices for the use of smart work zone technologies to improve safety in work zones. The development of the case examples will require an additional follow-up interview. Agencies participating in the case examples will be provided with an opportunity to review the case example write-up. The estimated time commitment for your agency for the case example is 1 to 1.5 hours for the follow-up interview and 1 hour to review the write-up. Would your agency be interested in participating in a case example? Yes 31% No 61% No Response 8% NOTES: Total number of respondents = 51. Table 22. Survey results for number of DOTs willing to participate in a case example.

Survey Results 63   ratings. There is a great deal of variability in the DOT performance ratings for smart work zone technologies, suggesting a wide range of DOT experiences. • Only 12% of DOTs indicated that they have completed evaluation or economic studies for smart work zone technologies. • The use of work zone data collection technologies appears to be growing, as they are employed by 33% of DOTs and planned for future implementation by an additional 37% of DOTs. However, only 31% of DOTs automatically collect data for work zone performance measures and store the data in a central location. • DOTs most commonly use performance measures collected for smart work zone technolo- gies to identify and mitigate project-level concerns, evaluate the performance of smart work zone technologies, and improve work zone policy and procedures. Crash statistics and queue length are the most frequently employed performance measures for assessing safety and opera- tional impacts of smart work zone technologies, respectively. Some DOTs are not yet ready to set and use performance measures for smart work zone technologies. • CMSs are most frequently used to disseminate traveler information, while the most common detection components are video cameras and traffic sensors. Approximately two-thirds of DOTs are using crowdsourcing data to collect information for smart work zone technologies to some extent. Cellular telephone and wireless ethernet are the communication components used most often by DOTs. • Almost two-thirds of DOTs install smart components (e.g., smart arrow boards) on existing non-smart equipment to some extent. • In selecting smart work zone technologies, DOTs most frequently consider traffic volumes, type of work, duration and length of the work zone, and existing traffic or safety issues. • Funding constraints and staffing shortages are the most reported obstacle to implementing smart work zone technologies as almost two-thirds of DOTs strongly or somewhat agreed that they hinder efforts. • The majority of DOTs have developed contract special provisions to support the implementa- tion of smart work zone technologies, while at least one-third of DOTs have also established specifications, guidelines, and concepts of operations.

64 This chapter presents case examples for the use of smart work zone technologies by seven state DOTs (Figure 44): Arizona, Colorado, Florida, Iowa, Massachusetts, Minnesota, and Oregon. In consultation with the topic panel, the following criteria were considered as a basis for choosing the DOTs for the case examples: • Diversity with respect to climate, level of experience, types of smart work zone technologies in use, scales of deployments (e.g., local versus statewide), AADT, and implementation challenges; • Use of innovative smart work zone technologies; • Level of detail provided in the survey comments; • Some preference given for DOTs with topic panel members; and • Willingness to participate in a case example, as indicated in the survey. Table 23 lists the DOTs selected for the case examples along with their implemented smart work zone technologies and basis for selection as a case example. The case examples were developed based on phone interviews with personnel from the seven DOTs. Some of the topics for smart work zone technologies during the interviews include the following: • General approach and experience; • Development of resources (e.g., specifications, standards, and tools) to support implementation; • Practices for collection of work zone data; • Use of performance measures; • Future plans to expand implementation; • Perceptions of gaps in existing knowledge; • Requirements for temporary traffic control, inspection, and material quality; • Cellular connectivity; • Implementation challenges; and • Project examples. The case examples are described in the following sections of this chapter. Arizona DOT Arizona DOT Implementation of Smart Work Zone Technologies The Arizona Department of Transportation (Arizona DOT) has implemented QWSs, traveler information systems, dynamic lane merge, and work zone data technologies. To disseminate traveler information such as travel time, roadwork, and status of message boards, the Arizona DOT makes frequent use of its 511 system (Arizona DOT 2021a). The Arizona DOT is using a queue warning and dynamic lane-merge system along with in-ground transverse rumble strips C H A P T E R 4 Case Examples

Case Examples 65   on a project to replace the Virgin River Bridge Number 1 on I-15 in northwestern Arizona. The Arizona DOT uses a customized smart work zone feasibility worksheet (Appendix F) to assess the need for smart work zone technologies for a given project based on criteria such as antici- pated work zone duration, traffic impacts, and queue lengths (Arizona DOT n.d.b). Arizona DOT sponsored a technical concept study on smart work zone technologies (Kimley- Horn and Associates 2020) that generated multiple resources to support implementation, including a smart work zone specification (Arizona DOT 2020), a spreadsheet to estimate work zone queue and delay, and a design tool that aids with the layout and quantity estimation for devices in smart work zones (Arizona DOT n.d.b). The technical concept study also developed a list of proposed performance metrics for smart work zones. The Arizona DOT pursues smart work zone initiatives in collaboration with the Maricopa County Department of Transportation (Maricopa County DOT) and other local agencies. Maricopa County DOT, the Arizona DOT, and other partner agencies obtained an FHWA grant to integrate data from various agencies into a countywide WZDx feed (Figure 45) (FHWA 2021b). In 2007, Maricopa County DOT, the Arizona DOT, and other partner agencies launched a connected vehicles program and constructed a test bed in Anthem, Arizona, in 2011 (Maricopa County n.d.). The Arizona DOT is also investigating commercial vehicle (CV) applications for smart work zones. The Arizona DOT is working on a pilot project to demonstrate the use of connected vehicle technologies to generate in-cab messages for CV operators and to support CV capabilities such as electronic screening and bypass (Kalina 2019). A conceptual drawing of the system is shown in Figure 46. In addition, the Arizona DOT is partnering with Embark, a developer of Figure 44. Map showing DOTs selected for case examples. (Map created with mapchart.net ©)