Principles and Guidance for Presenting Active Traffic Management Information to Drivers (2021)

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141 APPENDIX C: Research Question Evaluation Survey Principles and Guidance for Presenting Drivers with Dynamic Information on Active Traffic Management NCHRP Project 03-124 This NCHRP project includes a requirement to identify and prioritize research gaps, and to then conduct research to address high-priority gaps. There are 6 critical research questions that form the foundation for this project, as seen in the box below. Initial activities in this project have included a state of the practice review and a literature review. Based on the results of these two reviews, we have identified 13 research gaps; each is discussed below. While each of these research gaps relates to one of more of the critical research questions above, they contain additional detail and context about the underlying issue and provide further focus above and beyond the critical research questions above. Some of the research gaps include photos to help illustrate the nature of the problem or some aspect of current practices. All of the images presented below are cited earlier in the report. 1. DMS with a message about “low visibility” or “slow traffic ahead” can alert drivers to the need to reduce speeds, while dynamic speed limit signs can reduce the variability of the reduced speeds by providing a specific number. Dynamic speed limits are sometimes deployed as a standalone system or do not contain a message about why there is a reduced speed in place, and lack of driver understanding about the meaning of the signage can further hinder effectiveness. Does the provision of additional information Critical Research Questions for NCHRP 02-124 Q1. What information related to ATM strategies does a driver want and need? What characteristics are associated with this information (e.g., reliability, timeliness)? Q2. How much information can a driver process via the complementary and contrasting modalities (e.g., visual, auditory), given the context and distractions? Q3. What existing and potential media could be used to deliver this information? Media that are under the control of transportation agencies (e.g., electronic signs) are of primary interest but alternative and innovative media (e.g., in-vehicle displays, cell phone applications, geographic information systems) and their evolving capabilities and roles must be examined. Q4. Given a particular message and medium, what are effective ways to prioritize, format, and present the information to achieve a desired and safe response by drivers? Q5. How can an agency evaluate the return on investment of an ATM infrastructure or information technology decision? Q6. How can an agency balance the needs of drivers and the infrastructure costs, including maintenance and operations?

142 as an explanation to justify and encourage travel at reduced speeds increase the effectiveness of a dynamic speed limit with better speed compliance and lower average speed, e.g., “low visibility” or “congestion ahead” via supplemental DMS or dynamic elements on the dynamic speed limit signs? (Q1 or Q2) The photos below show three different ways that Oregon and Washington state display additional information with a dynamic speed limit. 2. Locations differ in the provision of static signage in advance of an ATM deployment with lane control signage, one example is shown in the photo below. This may be done for legal reasons for enforcement purposes; as a condition in the legislation allowing the deployment of a new strategy such as dynamic speed limits or a dynamic shoulder lane that is a change from current practices; or simply for informational purposes to help drivers understand. Is there a benefit of increased driver understanding in providing static signage in advance of ATM deployments to explain symbols? (Q1)

143 3. Dynamic information can be disseminated to drivers using various media, whether agencies provide information for drivers via infrastructure, to vehicles for in-vehicle messaging, to third-party providers for smartphone applications, or a combination of these approaches. What media is the best for disseminating dynamic information to satisfy driver wants and needs? Examination of this question in the context of dynamic queue warning may provide insightful results, as this dynamic information can be given to drivers without the presence roadside infrastructure. (Q1, Q3). 4. Dynamic information can be disseminated to drivers using various media, whether agencies provide information for drivers via infrastructure, to vehicles for in-vehicle messaging, to third-party providers for smartphone applications, or a combination of these approaches. What media for disseminating dynamic information achieves the lowest driver distraction, highest driver understanding and usage, and largest safety and mobility benefits? Examination of this question in the context of dynamic queue warning may provide insightful results, as this dynamic information can be given to drivers without the presence roadside infrastructure. (Q2, Q3, Q4) 5. As an alternative to deploying and maintaining a sign over each lane, a single dynamic message sign might present similar dynamic lane control information in the form of a pictogram. Are lane closure pictogram on a DMS understood by drivers, and is it equally or more effective than information presented via overhead dynamic lane control signs? (Q4)

144 6. In order to reduce the costs of deploying and maintaining ATM infrastructure, some agencies are considering alternatives that require less dynamic signage, which may use messages on DMS instead of overhead lane control signs or longer-distance intervals between gantries. Can dynamic information traditionally presented on lane control signs with supplemental DMS be presented on less signage in an equally or more effective manner? This may examine dynamic lane control, dynamic speed limits, or dynamic queue warnings as currently presented in urban areas on multipurpose overhead lane control signs, as seen in the photo below. (Q4) 7. Given the many variations in signage for dynamic speed limit deployments, what information and display for dynamic speeds is most effective for achieving driver understanding and reduced speeds? This may identify different approaches for advisory and regulatory speeds, different conditions, e.g., weather, work zones, and recurring congestion, and includes provision of static signs and supplemental information regarding the cause for a reduced speed, and consideration of a fully dynamic sign versus a sign with only dynamic digits. (Q4)

145 8. Is there a way to accurately quantify mobility-related benefits of an ATM deployment, or the safety-related benefits of a temporary ATM deployment? (Q5) 9. How can agencies systematically trade-off the various criteria associated with mobility, safety, cost, and driver needs when considering the deployment of ATM strategies? This question examines how agencies determine driver needs: what is accepted and will be used to inform travel choices, to justify the costs of investing in ATM strategies. (Q6) 10. Given a situation where multiple ATM media are available, what information do drivers want/how do drivers want to receive the information/when do drivers want to receive the information? This question focuses on drivers’ subjective preference without considering drivers’ performance or objective outcomes. Among the various ATM strategies, drivers’ preference regarding queue warning information will be asked (i.e., information type x ATM media x information receiving timing). (Q1) 11. Given a situation where multiple ATM media are available, what would be the most efficient and the least distracting modality (or modality combination) to deliver ATM information for the alternative/innovative ATM media? Especially for the alternative ATM media such as smart phones and in-vehicle displays, ATM information can be delivered by multiple modalities (e.g., auditory messages, visual messages, or combination of two). By utilizing previous guidelines (e.g., Campbell et al., 2016), which suggested how to select sensory modalities based on message complexity, receiving locations, information priority, etc., this question will examine the most efficient and the least distracting modality for the alternative ATM media when the ATM messages are available from both the alternative media (i.e., in the vehicle) and traditional electronic signs (i.e., outside of the vehicle). (Q2) 12. In the previous research, none of the reviewed studies deeply addressed integrated applications where both traditional ATM and alternative media (e.g., in-vehicle displays) are employed together. In a situation where multiple ATM media are deployed (e.g., electronic signs and in-vehicle displays), should they deliver the same information? Or should each medium need to play a specific role to compensate each other and to avoid redundancy? And what will be the best way to harmonize multiple ATM media (including traditional and alternative media) and how to evaluate the effectiveness/efficiency? (Q3)

146 13. There are available guidelines of ATM messages for the traditional media (e.g., electronic signs) and also available guidelines of general driver-vehicle interfaces. However, little to no research is available regarding structuring ATM message content (and symbols) for portable electronic devices/in-vehicle displays/mobile. What kind of ATM strategies/messages is practically feasible for shifting to smart phone applications/embedded in-vehicle displays? And which currently available guidelines can be used for this transition? And what are the gaps between currently available guidelines and requirements for presenting/formatting/prioritizing ATM messages on the alternative media? (Q4)