Pilot Testing of SHRP 2 Reliability Data and Analytical Products: Florida (2014)

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205 CHAPTER 7 Usability and Acceptability of the Products 7.1 Introduction This chapter presents observations concerning the usefulness of the products tested in the L38C project, a look at the issues identified by the research team related to those products, and a review of the level of understanding and acceptance by the stakeholders involved in the project. 7.2 Research Team Observations 7.2.1 L02 Products The new procedures, measures, and visualization techniques identified in the L02 project can be used as a powerful component of performance assessment and management. A number of issues identified by the research team have the capacity to improve the usefulness of the L02 product, as described below:  The L02 project focused on specific performance measures, including travel time rates and semivariance. L05 and L08 recommended using combinations of performance measures to assess reliability. The Florida DOT central planning office identified specific preferred performance measures. In the L38C project implementation, multiple performance measures were estimated and visualized to determine the issues on the facility. Additional visualization techniques were also used in the L38C project to support the implementation.  It was found that the analysis by time-of-day period was preferred to that based on congestion levels to allow separating different congestion patterns and associated causes as much as possible.  For operations and planning for operations purposes, analysis based on five-minute intervals was necessary to identify the exact times during which the system became unreliable to recommend the activation of advanced strategies.  The analysis was time consuming and requires knowledge and experience in transportation system analysis and advanced strategies. It is recommended that a data extraction and fusion tool be used to support the analysis. In addition, automation of the analysis is recommended as much as possible.  Overlapping conditions such as incident plus rain, incident plus construction, and construction plus rain should be considered. Incident plus rain conditions were analyzed in the L38C project.  For operational purposes, the analysis of reliability impacts by incident severity and rain intensity as done in this study is desirable.  As in the L38C implementations, the analysis should report both the total contribution of a certain event type to unreliability and the contribution of a single event to unreliability.

206 Both are important to planning and operations agencies. For example, incident plus rain events may have less frequency, and their contributions to overall reliability are small. However, a single incident plus rain condition has the highest impact on traffic.  Additional guidelines are needed regarding the aggregation of time intervals and the segmentation of highway facility based on the analysis scope. These guidelines may be location and scope specific.  A planning tool is needed to support agency decisions on the locations for additional data collection technologies to support reliability analysis, particularly for arterial streets, where installing such equipment on a large scale can be expensive.  The lingering effects of incident and weather events after the end of the events were not considered in this guide. These effects can be included in the analysis; however, some guidance is necessary.  The effects of downstream incidents were not considered in the guide or analysis.  The production of a high-level user guide may be useful to support agencies in their analysis. 7.2.2 L08 Freeway Facility Products L08 freeway products and the FREEVAL-RL tool can provide a strong platform for assessing the benefits of capacity improvements and incident management benefits for freeway facilities. The following issues related to these products were identified by the research team:  Traffic modeling using L08 tools should be calibrated to reflect observed operations. The calibration of the model required much less effort than that provided by calibration microscopic simulation models; however, the calibration required detailed data from multiple systems.  Updating scenario generator parameters based on local data produced reliability measurement values that were closer to real-world values.  FREEVAL-RL has a limited ability to assess active traffic and demand management strategies, such as variable speed limit, lane control, managed lanes, and ramp metering. Ongoing and previous related research and development results should be incorporated in the model.  Diversion during incidents was not modeled in FREEVAL-RL.  The scenario exclusion threshold affected the TTI values significantly. Better guidance is necessary regarding these values.  The calculation of reliability measures should be by time interval (e.g., 15 minutes) and by highway segment (or a subset of highway segments).  When evaluating alternative strategies by modifying certain parameters, such as incident duration and capacity adjustment factor, unexpected results were obtained in some cases. This issue is being discussed with the developer.  Based on discussion with the FREEVAL developers, the tool is being revised to allow more realistic release of ramp demands during congested conditions. This revision should

207 improve the modeling of the impacts of ramp metering; the current version seems to underestimate these benefits.  The tool should output additional TTIs, such as the 90th and 85th percentile TTIs.  It is recommended that the tool should allow the user to specify different incident rates and attributes for different time intervals.  Additional minor issues regarding the tool were found. For example, the ramp-metering button could not be edited after the seed file was created, and when using small percentiles to exclude scenarios, unrealistic results occurred (e.g., average travel time = 65535). 7.2.3 L08 Urban Street Facility Products In general, L08 STREETVAL-RL has good documentation and can reasonably model urban street reliability. Below is a list of findings and recommendations for L08 STREETVAL and STREETVAL-RL:  STREETVAL and STREETVAL-RL can simulate at most only eight segments.  Some input options had restrictive values or ranges in STREETVAL and STREETVAL- RL. For example, intersection width was limited to a range of 25 to 150 feet in STREETVAL, but one intersection in the study area had a width of 162 feet. The length of the stop line detector was limited to 1, 20, 40, 60, and 80 feet; however, the stop line detector had a length of 30 feet in this study. The input of saturation flow rate in STREETVAL was limited to 1,600 to 2,000 vehicles per lane, but for certain turning movements, even after the adjustment of left- and right-turn factors, the adjusted saturation flow rate was still less than 1,600 vehicles per lane. In STREETVAL-RL, the parameter inches of snow for one inch of precipitation required a value greater than zero; however, in states such as Florida, it has a value of zero.  There were no input options in STREETVAL for lane width, truck percentage, pedestrian counts, and so forth. To obtain the adjusted saturation flow rate, signalized intersections had to be coded in other software such as Highway Capacity software, which took almost the same time and effort as coding a STREETVAL model. Therefore, the suggestion is made to include those influential factors as input in the STREETVAL model so that the model has the ability to directly calculate the adjusted saturation flow rate.  Data from only one analysis period at a time could be input in the STREETVAL data set. An input of multiple time periods may better take into account the demand variation and also signal timing plan change among different time periods, for example, input at 15- minute intervals.  Even when two equal nonintegers were input for phase split, due to computer accuracy, a very small difference may have existed between these two numbers. For example, for a number of 10 –15 , STREETVAL would report an advisory error message indicating that these two phases had an unequal phase split.

208  The button size in STREETVAL-RL was not fixed, and the buttons may be enlarged after one or two runs.  The input of segment crash and work zone data was not differentiated between directions. Directional input of NB–SB and EB–WB information may better capture the impacts of incident and construction on travel time reliability.  Although the L08 project developed an elegant methodology to take into account incident type, lane blockage, and corresponding weather conditions, for most of applications, it is extremely difficult to get such detailed crash and incident information on arterials.  A threshold similar to the one used in FREEVAL-RL could be applied in STREETVAL- RL to cut off the extreme scenarios.  Better guidance and documentation are needed for handling the error code reported during the run time of STREETVAL-RL.  It took several hours to run one STREETVAL-RL case study. When there was any error with one of scenarios, all the scenarios had to be rerun, which took another several hours. If the program could resume the calculation starting from the scenario with the error, it would save a lot of time.  Performance output of STREETVAL-RL only reported the various travel time values, not the travel time reliability index. Instead of outputting performance for each segment separately, it is suggested to output all the segments’ performance at the same time for the purpose of comparison. 7.2.4 L07 Products The L07 spreadsheet can be adapted for use in analyzing improvement alternatives. The research team made the following observations:  The output from the tool should be saved to tables in addition to being displayed in graphs.  The tool should allow more flexibility in the input parameters, such as allowing the user to input adjustment factors for capacity.  There is a need for future work on creating a similar sketch-planning tool for arterial streets.  Guidance is needed for setting spatial limits for evaluating the impacts of improvement alternatives, because these limits will significantly influence the estimated benefits. These recommendations should take into consideration the areas of influence of the specific improvement alternatives under evaluation. There is a need to extend the tool to include additional strategies normally considered by agencies and a need to provide guidance or allow the user to assess time-dependent management strategies.  It was found that the default reliability models may not be applicable for all segment lengths and that they produced different accuracies depending on segment lengths. This issue needs to be investigated further.

209  Additional issues with the user interface included the following: the geometry inputs could not be saved, the subtotal for noncrash incidents did not change when input changed, incident data could not be saved, and the interface did not fit on all computers. 7.2.5 L05 Products The L05 products were helpful in setting the evaluation and implementation plan for the project and in stakeholder involvement during the project. A useful aspect of the L05 project was the guidance provided regarding how to identify tools, performance measures, thresholds and deficiencies, and the visualization of performance. The general guidelines regarding identifying the agency business processes were also helpful. 7.3 Understandability and Acceptability by Stakeholders Stakeholder workshops were conducted at the beginning (June 20, 2013) and end (May 21, 2014) of the project. The purpose of these workshops was to share the objectives and results of Pilot Testing of SHRP 2 Reliability Data and Analytical Products with project stakeholders. A summary of the interactive discussions with the stakeholders at the May 21, 2014, workshop is presented below. SHRP 2 products can be used for a diverse range of planning and operations applications. The planning applications include development of TIPs, LRTPs, TSM&O plans, corridor studies, and PD&E studies. The operations applications include arterial operations, freeway and toll road operations, transit operations, and freight operations. Reliability reporting should be coordinated with statewide efforts for planning and operations. Automated tools such as the ITSDCAP reliability module will be useful to help implement reliability as additional input to agency business processes. The reliability estimation requires a good understanding of data as it uses an extensive amount of data for reliability calculations. Thus, automated tools are necessary to help in this effort Although CDF and PDF curves are valuable analytical tools, they may be too difficult to apply for nontechnical users and audiences. Animated or video tools may be useful, as well as other methods to convey the same message to nontechnical audiences (e.g., policy makers). The challenges in conveying the meaning and importance of travel time reliability to nontechnical audiences will be in presenting the information in simple visual graphics or video animations. It was suggested that a common definition be selected from the many possible definitions of travel time reliability (e.g., TTI, buffer index, misery index) and used consistently in presentations to nontechnical audiences. It will be useful to incorporate travel time reliability into the planning process to better assess capacity improvements versus operations improvements. For planning applications, it was suggested that the reliability tools begin to be applied to corridor studies, then evolve into regional planning applications. Travel time reliability can be used in qualitatively developing TIP and LRTP goals and objectives, as well as quantitatively as a measure of effectiveness in evaluating improvement projects. The MPO will need to assess this in developing plans. For LRTPs, the CDF and PDF graphs are too detailed and too technical. Simple graphics indicating reliability performance

210 levels are preferred. The more technical outputs of the reliability tools may be more applicable to corridor planning studies than to LRTPs. High-level tools (such as those developed in Projects C11 and L07) can be used to evaluate reliability in long-range plans, as these tools are easy to use. Reliability can be incorporated into corridor study scope of services and for alternatives analysis and should be used in the ongoing I-95 implementation plan and SR-7 in Miami-Dade County. As part of PD&E studies and alternatives analyses, travel time reliability should be considered as a possible measure of effectiveness in comparing project alternatives in addition to other measures of effectiveness (e.g., costs, right-of-way impacts, delay savings, crash reduction, emission savings, benefit–cost ratio) that are traditionally used. Travel time reliability performance reports are already being generated by Florida DOT District 6 TMC for all Interstate facilities within Miami-Dade County by direction and by hourly time frames. These monthly reliability reports are archived on their website. District 4 generates monthly reports for the arterial and freeway system, but it does not yet include travel time reliability reports. However, these reports are not used adequately for operations and planning for operations tasks. District 6 is interested in applying travel time reliability as input to developing predictive models and decision support systems to be more proactive in addressing both recurring and nonrecurring congestion. The challenges will be applying travel time reliability to develop accurate predictive models that can provide input to decision support systems. This change may begin with selected applications, such as applying this information to make decisions concerning activating ramp signals earlier than peak periods or adjusting ramp signal release rates. The Miami-Dade County Traffic Signal agency recognizes that the reliability products can help develop and implement better signal timing plans; however, their constrained staff resources are a concern in applying travel time reliability in their operations. Therefore, automated tools would be needed to make them more useful without creating a burden on their staff. Reliability is helpful in comparing multimodal alternatives. Miami-Dade Transit is applying travel time reliability as a performance measure for transit signal priority along Kendall Drive. Travel time reliability should also be considered for freight traffic. Freight carriers can use reliability as part of the dynamic routing and dispatching of their truck fleets. Travel time reliability may be used by the media as part of traffic reports to supplement the real-time camera images they use and the travel time information they report along selected links within the regional highway network. This information may also be used by the private sector in developing smartphone apps to report real-time travel time reliability to supplement the congestion-level information currently being displayed. It may be useful to provide reliability information, as well as speed and travel time information, to travelers.

211 Although visualization tools (e.g., heat maps) are useful to technical staff, relating reliability data to geography is more important for the public. A time variation of data using video would be useful. Reliability data need to be marketed to help the public understand the concept (e.g., simple color-coded maps indicating the level of travel time reliability as opposed to PDFs). The public may have a different understanding of reliability (e.g., leave early or arrive on time) than traffic analysts and will find PDFs difficult to understand. It is important to further demonstrate the applicability of reliability in the real world. Its importance needs to be emphasized. More funding is needed to support the integration of reliability as part of the planning and operations processes. A survey was conducted at the beginning and end of the May 21, 2014, workshop to gauge the level of understanding that the stakeholders had regarding the research. Although the survey was not conducted to provide statistically accurate conclusions, the following inferences may be drawn:  Most participants were familiar with the concept of travel time reliability.  Most participants believed, particularly after the completion of the workshop, that travel time reliability can be quantified.  The participants had not seen travel time reliability used frequently as part of project evaluations.  The participants had not seen their agencies frequently use travel time reliability in a program or planning application.  All participants believed that the evaluation of travel time reliability will likely or very likely be used in the future.  The participants believed that the following planning and study applications of travel time reliability (in order of importance) are the most promising: corridor and multimodal studies; followed by PD&E studies; followed by interchange modification reports and MPO LRTP, TIP, and CMP studies.  The participants believed that the following operations applications of travel time reliability are equally promising: freeway real-time TMC operations, signal agency center operations, TSM&O applications, planning for operations, and transit and freight operations.  The participants believed that the following barriers (in order of importance) are most likely to impede an agency’s ability to evaluate travel time reliability: staff and time resources, followed by data availability, resistance to change, staff expertise, and believing that existing methods are adequate. In summary, the workshops were successful in presenting the objectives and results of the research, providing high-level training, and introducing how the reliability data and analytical products may begin to be integrated within transportation planning and operations business processes. Positive feedback was provided by the stakeholders.

212 7.4 Next Steps Pilot Testing of SHRP 2 Reliability Data and Analytical Products: Florida Pilot Site provides a foundation for beginning to integrate travel time reliability into the planning and operations business processes. Rolling out of the implementation should consider the following steps:  High-level training. High-level training should be conducted among the various agency stakeholders to bring everyone up to the same level of understanding regarding the reliability tools. In essence, such training would be an extension of the preliminary training provided at the stakeholder workshops.  Guidelines. The L05 guidelines and possibly additional guidelines should be communicated to stakeholders for each planning and operations process. The communicated guidelines would address using reliability in the development of short- and long-range transportation plans, transportation systems management and operations planning, and corridor and PD&E studies. For operations, reliability should be addressed in developing performance management systems and amending standard operating guidelines for active arterial management, freeway and toll road operations, transit operations, and freight management.  Pilot projects. Specific pilot projects should be identified for each planning and operations process to demonstrate how reliability may be integrated into and used to enhance the process. Pilot projects pertaining to planning may include incorporating reliability qualitatively, as part of goals and objectives for TIPs and LRTP updates, or quantitatively, as a measure of effectiveness in comparing alternatives as part of a corridor or PD&E study. Pilot projects pertaining to operations may include establishing performance measures for reliability on arterial, freeway, toll road, transit, and freight systems, then measuring them in a real-time or predictive manner.  Refinement of guidelines. The L05 and other guidelines developed for each planning and operations process should be refined based on the findings of the pilot projects. This refinement should be part of a continuous improvement process for planning guidelines and standard operating guideline updates.  Detailed training. Detailed training materials should be developed for each planning and operations process based on the refined guidelines. These training materials should be used to conduct training for stakeholder agency staff along with certification testing to ensure that staff comprehend the reliability concepts and analytical tools.  Performance management. Performance management systems, in measuring reliability, should be developed using automated processes to provide timely, useful, and accurate reports while not placing additional burden on technical staff in developing these reports using manual processes. These performance management systems should be integrated as part of updates on websites to transparently share this information with agency stakeholders and the public.  Implementation. Reliability should be integrated into each planning and operations process by using appropriate software tools. Planning tools should be used to support

213 alternatives analyses, project prioritization, and justification. For operations, predictive models and decision support system applications should be considered to facilitate proactive transportation systems management and operations.  Public education and outreach. A simple reliability definition should be selected, among the many definitions available, and used as part of a public education and outreach effort so that executive, management, and technical staff will understand it as well as the public. In addition, third-party traveler information providers should be contacted to determine if there is an interest in developing smartphone apps or incorporating reliability information as part of media traffic reports. In summary, the SHRP 2 Reliability Program has made significant investments in developing products to support estimating travel time reliability, identifying reliability deficiencies and contributing factors, identifying alternative solutions, and analyzing the impacts of these solutions. The return on these investments will be realized by integrating reliability in planning and operations processes by using the phased approach described above. These actions will support one of MAP-21’s goals in integrating performance estimation, measurement, and management in each state.