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Suggested Citation:"Chapter 6 - Communicating Results." National Academies of Sciences, Engineering, and Medicine. 2021. Application of Crash Modification Factors for Access Management, Volume 1: Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/26161.
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Suggested Citation:"Chapter 6 - Communicating Results." National Academies of Sciences, Engineering, and Medicine. 2021. Application of Crash Modification Factors for Access Management, Volume 1: Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/26161.
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Suggested Citation:"Chapter 6 - Communicating Results." National Academies of Sciences, Engineering, and Medicine. 2021. Application of Crash Modification Factors for Access Management, Volume 1: Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/26161.
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Suggested Citation:"Chapter 6 - Communicating Results." National Academies of Sciences, Engineering, and Medicine. 2021. Application of Crash Modification Factors for Access Management, Volume 1: Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/26161.
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Suggested Citation:"Chapter 6 - Communicating Results." National Academies of Sciences, Engineering, and Medicine. 2021. Application of Crash Modification Factors for Access Management, Volume 1: Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/26161.
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Suggested Citation:"Chapter 6 - Communicating Results." National Academies of Sciences, Engineering, and Medicine. 2021. Application of Crash Modification Factors for Access Management, Volume 1: Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/26161.
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Suggested Citation:"Chapter 6 - Communicating Results." National Academies of Sciences, Engineering, and Medicine. 2021. Application of Crash Modification Factors for Access Management, Volume 1: Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/26161.
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Suggested Citation:"Chapter 6 - Communicating Results." National Academies of Sciences, Engineering, and Medicine. 2021. Application of Crash Modification Factors for Access Management, Volume 1: Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/26161.
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108 The objective of this guide is to assist transportation agencies in quantifying the safety impacts of their decisions related to access management. The safety performance can then be used in the decision process to compare against other quantitative measures (e.g., costs, operational efficiency, and environmental impacts) or perceptions (e.g., fairness, convenience, and competi- tiveness related to property access and businesses). While the methods in this guide can help to quantify safety performance and identify safety-beneficial alternatives, the effort is futile unless decision-makers use the results to inform decisions. As such, there is a need to clearly and concisely communicate the analysis results to various audiences. To do so, it can be useful to engage com- munication experts in the effort. The guidance can serve the needs of both technical and non-technical audiences. These audi- ences may include planners, designers, policy-makers, regulatory staff, and public stakeholders. It is important to select and employ appropriate communication approaches and mecha- nisms to effectively reach both technical and less-technical audiences. Furthermore, within each audience, the communication tools and methods need to effectively educate and sup- port the potentially wide range of expertise and interest. This chapter defines potential target audiences, identifies communication methods, and describes different measures and formats for presenting the results of safety analyses to effectively convey the key details to technical and non-technical audiences. Regardless of the audience, method, measure, and format, one common theme is the need to engage communication experts throughout the process. Audiences Technical Audience The technical audience for this guide includes safety analysts, program managers, project managers, and operational staff involved with project planning, design, development, imple- mentation, and operation, as well as project, strategy, and program evaluations. This audience includes staff working on roadway improvement projects that may be at various levels of granu- larity (e.g., corridor, segment, intersection, or site level). The research results are intended to support the decision-making process by quantifying the benefits for comparison against other benefits and the costs of different improvement options. It is becoming more common for the technical audience to be familiar with or knowledge- able of the Highway Safety Manual (1st Edition) (AASHTO 2010) and the CMF Clearinghouse (FHWA n.d.). For example, traffic engineers, safety engineers, and researchers are often involved with the development and application of CMFs, SPFs, and related research. While the tech- nical audience may have some degree of familiarity with CMFs and SPFs, there are significant C H A P T E R   6 Communicating Results

Communicating Results 109   differences in levels of expertise and experience in applying CMFs and SPFs to quantify safety performance and understanding and correctly interpreting the results. The following is a list of potential audiences from the transportation planning, design, regula- tory, and operational community that will benefit from the information provided in this guide: • Agency (state, regional, and local) planning and regulatory staff; • Agency design, operations, and maintenance staff; • The development community; • Consultants (agency and development support); • Transportation and safety research communities; and • Agency policy-makers and decision-makers (some appointed). Non-Technical Audience Members of the often less-technical audience, which can include elected officials and active community organizations, can be equally important and sometimes even more important in invest- ment and policy decisions. This audience is typically interested in the results and may or may not be interested in how the results are obtained. The following is a list of potential members of the non-technical audience that will benefit from the information provided in this guide: • Agency policy-makers and decision-makers (some appointed), • Elected official policy-makers and decision-makers, • The development community, • Advocacy organizations, • Media, and • The public. Methods Effective communication is well-timed, deployed through a variety of mechanisms, and tailored to the needs of the audience. The purpose of the outreach is generally the same for both audiences— provide justification for the project design—but the messaging method will differ. This section briefly introduces considerations for effective communication with technical and non-technical audiences, while the subsequent section provides additional information on the measures and message content. Technical Audience Technical audiences can use the research presented in this guide to influence decisions both upstream and downstream. In the downstream approach, communication methods are selected with the intent to share the results with other technical audiences to influence project develop- ment, support decision-making, and provide tools and resources for justification on a project level. These methods involve circulating information to technical audiences on the state and local levels to integrate or inform their decision-making. For example, planning-level analyses could be passed along to highway designers during project development to inform detailed design decisions. This can be accomplished using technical memos, brochures, and other concise outreach tools to provide summaries of the key technical takeaways and measures presented in the next section in an easy-to-use format. Deployment requires few resources and quickly reaches target audiences of technical engi- neers and analysts. The tradeoff is this approach targets engaged and interested audiences while having minimal impact on audiences not actively seeking new technical information.

110 Application of Crash Modification Factors for Access Management While the upstream approach is not the focus of this chapter, it is aimed at influencing state- wide processes and policies. Analysts can achieve this through enhanced coordination between state agencies, such as creating or joining multidisciplinary groups composed of technical audi- ences (Beer et al. 2018). Through regular meetings and ongoing communication, partners iden- tify opportunities for collaboration and coordination among offices and agencies. Analysts share the measures discussed in the next section and encourage integrating the results into planning and development decision-making processes; this is a proactive, top-down approach where safety is considered earlier in the project development process, leading to more opportunities for enhanced safety performance in the completed project. Multidisciplinary groups can also communicate safety information to external audiences, both technical and non-technical. Public affairs offices, highway safety offices, and other similar agencies have the skillsets and resources for communicating with larger audiences (Beer et al. 2018). A collaborative group can be responsible for developing safety messaging and identi- fying appropriate methods to educate and engage both technical and non-technical audiences. Technical memos, brochures, instructional videos, public service announcements, and general graphics or visuals are all useful tools for reaching both technical and non-technical audiences. This approach develops interpersonal relationships and improves communication among agencies; however, this requires time, staff resources, designated champions, and willingness to collaborate. Non-Technical Audience Communication with non-technical audiences also focuses on project justification but occurs further downstream in the project planning and development phases. Many methods developed for technical audiences—videos, graphics, public service announcements—are applicable for policy-makers, decision-makers, the media, and the public, but may need adjustments. Analysts should not assume this audience is informed about the technical aspects of a project and should tailor methods accordingly. It is important to include an education component in the messaging that can be comprehended by any reader no matter their knowledge background. This is also an opportunity to engage with land developers to produce case study examples of similar projects, demonstrating applicability and successes. Mapping technologies, aerial videos, and computer animations are all appropriate methods for reaching non-technical audiences. As discussed in the next section, concepts like lives saved or return on investment are sensitive topics and should be approached in a positive fashion. Messages and methods should focus on the positive out- comes with a human element. Communication is a two-way street. Engaging and collaborating with audiences that hold diverse viewpoints can introduce insights not previously considered into a project. Measures Introduction Traditional safety performance measures have predominately relied on historical (observed) crashes and longer-term (multi-year) average crash frequency and severity metrics. With the advent of the Highway Safety Manual (1st Edition) and data-driven safety analysis methods, there are additional quantitative approaches to complement traditional crash rates, frequen- cies, and severities. As described in Appendix B, these more reliable methods allow analysts to estimate future crashes (by type and severity) with and without proposed improvements or changes to the design and operations of the roadway. It is now possible to consider and analyze measures such as lives saved, injuries prevented, and safety benefit-cost ratios for alternatives.

Communicating Results 111   It is important to consider the target audience and the communication method when selecting a measure to present and represent the results. Technical audiences may be interested in the estimated number of crashes by type and severity for the various alternatives as well as the benefit-cost ratio. Policy-makers and decision-makers may be more interested in the return on investment in terms of the monetary value or number of lives saved per dollar spent. Such measures are best communicated through succinct technical briefs or memos with supporting graphical representations. The public may not fully understand the more technical measures such as benefit-cost ratio or the predicted or expected number of crashes, particularly when presented as decimals. Further, the public may perceive a benefit-cost analysis as callous because there is a dollar value assigned to death and injury. As such, the preferred measure for public meetings may be the number of lives saved and injuries prevented over the life of proposed alternatives compared to the existing (or no-build) scenario. If results are presented to the public in terms of estimated crashes (total or by severity), it is useful to present the results over a longer period of time (e.g., 10 or 20 years) to avoid small numbers and decimals. For example, an estimated crash reduction of 0.30 crashes per year may not resonate in a public meeting, but the same information could be presented in a way that connects emotionally with the audience as “three lives/neighbors saved in 10 years.” Graphical representations and succinct methods of relatable communication are best for non-technical audiences like the public or decision-makers. Example An example can show three ways to present the same information: (1) expected number of crashes per year by severity, (2) benefit-cost ratio, and (3) lives saved and injuries prevented over the life of the project. In this example, an agency is considering the installation of a non- traversable median in place of an existing TWLTL on a four-lane suburban arterial. The posted speed is 45 mph, the traffic volume is 35,000 vehicles per day, and the corridor length is 1.0 mile. There is a desire to estimate the change in crashes by severity, the benefit-cost ratio, and the number of lives saved and injuries prevented. The analyst identifies applicable CMFs from Chapter 3 (Table 17). The applicable CMF for fatal crashes is 0.70 (CMF Clearinghouse ID 5152), the applicable CMF for injury crashes is 0.70 (CMF Clearinghouse ID 5150), and the applicable CMF for PDO crashes is 0.78 (CMF Clearing- house ID 5149). This example assumes the CMF for injury crashes (i.e., all A-, B-, and C-level crashes combined) applies to each individual injury severity, which may over- or under-estimate the safety impacts if the assumption is not valid. Table 74 shows the long-term average crashes per year by severity under base conditions for the hypothetical scenario with a TWLTL, the CMFs for the respective crash severity levels, the estimated crash frequency with non-traversable median, and the expected change in crashes by severity. For example, the estimated number of annual K-level crashes under base conditions is 0.1 crashes per year and the applicable CMF is 0.70. Applying the equation in Figure B-8 results in an estimate of 0.07 K-level crashes per year Table 74. Estimated annual crashes by severity. Crash Severity Estimated Annual Crashes for Base Condition Applicable CMF Estimated Annual Crashes with Treatment Estimated Annual Crash Reduction Fatal Injury (K) 0.1 0.70 0.07 0.03 Suspected Serious Injury (A) 1.2 0.70 0.84 0.36 Suspected Minor Injury (B) 2.4 0.70 1.68 0.72 Possible Injury (C) 4.0 0.70 2.80 1.20 No Apparent Injury (O) 10.0 0.78 7.80 2.20 Total 17.7 -- 13.19 4.51 Note: -- indicates not applicable.

112 Application of Crash Modification Factors for Access Management with treatment (0.7 p 0.1). The difference is an estimated change (in this case a reduction) of 0.03 K-level crashes per year. The net safety benefit is the sum of the estimated change in crashes by severity. In this case, the net safety benefit is a reduction of 4.51 crashes per year (17.7 crashes under base conditions – 13.19 crashes with treatment). It appears this alternative will provide a safety benefit; however, it may be desirable to determine if the benefit is worth the cost of the treatment. To estimate the monetary benefit, it is important to apply crash costs by severity to the esti- mated change in crashes by severity before aggregating benefits across severity levels. Table 75 shows the estimated annual change in crashes from Table 74, the average crash costs by severity (Lawrence et al. 2018), and the estimated annual monetary safety benefit. The estimated annual monetary benefit is the product of the estimated annual change in crashes and the average crash cost for the respective severity level. For example, the estimated annual change in A-level crashes is 0.36 crashes per year, and the average cost of an A-level crash is $674,353. The result is a safety benefit of $242,767 per year (0.36 A-level crashes per year p $674,353 per A-level crash). Aggre- gating the annual monetary benefits across severity levels indicates the net monetary safety benefit. In this example, the installation of a non-traversable median is expected to provide a net safety benefit of $920,327 per year. To estimate the benefit-cost ratio, there is a need to estimate the construction costs and annual maintenance costs associated with the treatment of interest. Then, there is a need to convert the annual monetary benefits into present value benefits. Similarly, there is a need to convert the annual maintenance costs into present value costs. Finally, the benefit-cost ratio is computed as the ratio of present value benefits to present value costs (including both construction and main- tenance costs). Refer to the Highway Safety Manual (1st Edition) and Highway Safety Benefit- Cost Analysis Guide (Lawrence et al. 2018) for further details on monetizing safety benefits and performing benefit-cost analysis. For this example, it is assumed that the present value benefit is $13,692,146 based on a service life of 20 years and a discount rate of 3.0 percent. It is also assumed that the present value cost is $225,000 based on a 4-foot wide median and a construc- tion cost of $10 per square foot (Bushell et al. 2013). In this case, the benefit-cost ratio would be presented as 60.85 or $60.85 in safety benefits for every $1.00 invested. So far, this example has focused on highly detailed estimates of safety performance, which may be of interest to technical audiences, as well as the return on investment, which may be of interest to decision-makers to support financial decisions. To bring this back to the goal of many safety programs (i.e., to reduce fatalities and serious injuries on all public roads) and provide information that may resonate more strongly with the public, it may be desirable to present these results in terms of lives saved and injuries prevented. Based on the results presented in Table 74, the lives saved from the project is approximately 0.03 per year (0.10 – 0.07) or 0.6 lives over the 20-year service life of the project. Similarly, the Crash Severity Estimated Annual Crash Reduction Average Crash Cost by Severity Estimated Annual Monetary Safety Benefit Fatal Injury (K) 0.03 $11,637,947 $349,138 Suspected Serious Injury (A) 0.36 $674,353 $242,767 Suspected Minor Injury (B) 0.72 $204,143 $146,983 Possible Injury (C) 1.20 $129,001 $154,801 No Apparent Injury (O) 2.20 $12,108 $26,638 Total -- -- $920,327 Note: -- indicates not applicable. Table 75. Estimated annual monetary safety benefit by severity.

Communicating Results 113   number of suspected serious injuries prevented from the project is approximately 0.36 per year (1.2 – 0.84) or 7.2 suspected serious injuries over the 20-year service life of the project. The injuries prevented could be presented in various levels such as suspected serious injuries (A-level inju- ries) or all injuries (A-, B-, and C-level). It may also be reasonable to combine the fatalities and suspected serious injuries as a single number (e.g., approximately 8.0 lives saved and suspected serious injuries prevented over the 20-year service life in this example). Note the results in Table 74 are presented in terms of crashes, so the previous numbers only represent an approximation of the lives saved and injuries prevented. Nationally, there is an average of 1.09 fatalities per fatal crash and 1.44 injuries per injury crash, based on data from 2010 through 2017 (NHTSA 2020). Converting the previous numbers of crashes to fatalities and injuries based on these factors, the project would result in more than 11.0 lives saved and suspected serious injuries prevented over the 20-year service life. If an agency has similar values that represent the local factors to convert fatal and injury crashes to fatalities and injuries, then that would provide a more reliable estimate. Format Depending on the target audience and purpose of the safety analysis, there is an opportunity to balance the simplicity of tabular information with creative graphical displays to present multiple dimensions of the analysis. The technical audience may be more interested in the equations and other information needed to quantify the safety impacts of different access management features. The non-technical audience may focus on the results and implications of applying the results on a personal level, not the calculations used to produce them. The non-technical audience may have concerns about how the project will affect aspects of their lives beyond the element of safety. Will the change impact commute time, taxes, aesthetics of the neighborhood, or walkability? Undesirable guaranteed changes can be challenging to accept against potential future lives saved unless the audience is invested emotionally. The understanding that the lives saved could be community members—neighbors, co-workers, friends, and family—is important to having audiences vested in the project. The technical details, such as the equations, limitations, and assumptions may be of less interest. To effectively inform decisions, the results must be understandable and presented in a clear and concise manner. As a result, the nature of the information provided to the non-technical audience may need to be less numerical and more graphical or narrative in nature. For example, a case study can be useful for demonstrating successes of similar projects, and the closer in prox- imity the case study is to the subject location, the better. This section provides several format options for presenting and displaying safety analysis results in tabular and graphical formats with various levels of supporting information. Most visuals are intended to be accompanied by a knowledgeable speaker who can interpret the results for the audience and engage in a question-and-answer session. Standalone graphics on posters or takeaway flyers should be a more visual style and highlight key details from the data. The following subsections are structured around the three primary measures: estimated crashes, benefit-cost ratio, and lives saved and injuries prevented. Estimated Crashes Technical audiences may be interested in the estimated crashes (observed, predicted, or expected) for each alternative, potentially by crash type or severity. This type of information is typically presented in tabular format, as shown in Table 76. For this example, consider a scenario

114 Application of Crash Modification Factors for Access Management where an agency is considering the conversion of a two-way stop-controlled intersection along an urban arterial to a signalized intersection or a single-lane roundabout. The base condition represents no change in existing conditions (i.e., maintaining the urban, two-lane, two-way stop-controlled intersection), Alternative 1 is the traffic signal, and Alternative 2 is the round- about. Refer to Appendix B for background on observed, predicted, and expected crashes, and refer to Chapter 4 for more details on the predictive method to estimate the safety performance of various intersection types. When presenting these results to a technical audience, it generally would be necessary to clearly define terms such as observed, predicted, and expected crashes as well as the categories used to represent crash types or crash severity levels. When presenting these types of results to a mixed audience of technical and non-technical stakeholders, it would be important to simplify the terminology as much as possible while still presenting sufficient detail. For example, if it is important to maintain some breakdown of crash severity, it might be useful to show two or three categories that represent fatal, injury, and PDO crashes. This would be more informative than showing the change in total crashes while simplifying the number of crash severity levels and related terminology. Table 77 shows another way to present this information, focusing on the change in crashes compared to the base condition (no-build scenario). This shows that both alternatives are expected to provide a safety benefit compared to the existing condition, but Alternative 2 is expected to pro- duce a greater benefit than Alternative 1. This information can be shown in terms of the change in crash frequency, the percent change, or both. An alternative to presenting this information in tabular format is to use bar or pie charts, as shown in Figures 126 and 127, respectively. The size of the bars in the bar chart and the size of the pie in the pie chart represent the magnitude of the overall crashes; the slices show the proportion Crash Severity Estimated Annual Crashes for Base Condition Estimated Annual Crashes with Alternative 1 Estimated Annual Crashes with Alternative 2 Fatal Injury (K) 0.050 0.048 0.031 Suspected Serious Injury (A) 0.670 0.637 0.409 Suspected Minor Injury (B) 0.790 0.751 0.482 Possible Injury (C) 3.670 3.487 2.239 No Apparent Injury (O) 8.670 8.237 5.289 Total 13.850 13.160 8.450 Table 76. Example comparison of estimated annual crashes by severity. Crash Severity Estimated Reduction in Annual Crashes with Alternative 1 (compared to base condition) Estimated Reduction in Annual Crashes with Alternative 2 (compared to base condition) Fatal Injury (K) 0.00 0.02 Suspected Serious Injury (A) 0.03 0.26 Suspected Minor Injury (B) 0.04 0.31 Possible Injury (C) 0.18 1.43 No Apparent Injury (O) 0.43 3.38 Total 0.69 5.40 Percent Change 5% 39% Table 77. Example comparison of estimated change in annual crashes by severity.

Communicating Results 115   of crashes by severity. When presenting these results to non-technical audiences, it might be useful to describe the relative size of the bar and pie charts as well as the overall percent change in crashes as opposed to the percent change in each severity level. Benefit-Cost Ratio Technical audiences and decision-makers may be interested in converting the estimated safety benefits for each alternative to monetary benefits and comparing the monetary benefits to the monetary costs through the benefit-cost ratio. This type of information may be pre- sented in tabular format as shown in Table 78 or in graphical format as shown in Figure 128. The information shown in Table 78 and Figure 128 is from the example where an agency is comparing the safety performance and potential benefits of converting an existing two-way stop-controlled intersection along an urban arterial to a signalized intersection or a single- lane roundabout. Further, the analysis is based on a 20-year study period, a discount rate of 3.0 percent, a 10-year service life for Alternative 1, and a 20-year service life for Alternative 2. Table 78 shows present value costs, present value benefits, benefit-cost ratio, and supporting details for each alternative compared to the no-build scenario. The monetary safety benefit is based on the crash reductions from Table 77 and the average crash costs by severity that were used previously (Lawrence et al. 2018). Figure 128 shows this same information graphically, focusing on the present value costs and benefits. If there are other categories of benefits (e.g., operational, environmental, etc.), then these could be shown in the table as other annual benefits or presented graphically as illustrated in Figure 129. Simple graphics can enhance communication, providing a visually informative display of results. While these graphics may appear overly simplistic to a technical audience, they can assist 5% 0 2 4 6 8 10 12 14 16 39% Estimated Annual Crashes for Alternative 1 Comparison of Crashes by Severity No Apparent Injury (O) Suspected Minor Injury (B) Possible Injury (C) Suspected Serious Injury (A) Fatal Injury (K) Estimated Annual Crashes for Alternative 2 Estimated Annual Crashes for Base Condition Figure 126. Example bar chart presentation of crashes by severity for alternative comparison.

116 Application of Crash Modification Factors for Access Management ~13 crashes per year 5% fewer crashes 39% fewer crashes Fatal Injury (K), 0.031, 0% Fatal Injury (K), 0.048, 0% Fatal Injury (K), 0.05, 0% Possible Injury (C), 2.239, 26% Possible Injury (C), 3.487, 26% Possible Injury (C), 3.67, 26% Suspected Minor Injury (B), 0.482, 6% Suspected Minor Injury (B), 0.751, 6% Suspected Minor Injury (B), 0.79, 6% Suspected Serious Injury (A), 0.409, 5% Suspected Serious Injury (A), 0.637, 5% Suspected Serious Injury (A), 0.67, 5% No Apparent Injury (O), 5.289, 63% No Apparent Injury (O), 8.237, 63% No Apparent Injury (O), 8.67, 63% ~14 crashes per year ~8.5 crashes per year Estimated Annual Crashes for Alternative 2 Estimated Annual Crashes for Alternative 1 Estimated Annual Crashes for Base Condition Figure 127. Example pie chart presentation of crashes by severity for alternative comparison.

Communicating Results 117   Figure 128. Example presentation of present value costs and benets for alternative comparison. Figure 129. Example presentation of multiple benet categories. $1,319,183 $900,000 $1,100,000 $200,000 $50,000 SAFETY TRAVEL TIME RELIABILITY VEHICLE OPERATING COST EMISSIONS Alternative 1: Summary of Present Value Benefits Measure Alternative 1Traffic Signal Alternative 2 Roundabout Service life (years) 10 20 Construction cost $300,000 $900,000 Annual maintenance cost $8,000 $0 Present value of reconstruction and maintenance costs $329,967 $0 Total Present Value Cost $629,967 $900,000 Annual monetary safety benefit $88,670 $691,625 Total Present Value Benefit $1,319,183 $9,989,932 Benefit-Cost Ratio 2.1 11.1 Table 78. Example presentation of benet-cost ratio with supporting details.

118 Application of Crash Modification Factors for Access Management in the understanding and interpretation of results, particularly for public officials and the public. It may be easier for a non-technical audience to interpret a side-by-side graphical comparison, such as a bar chart, than it is to interpret two columns of numbers in a table. Lives Saved Technical and non-technical audiences may be interested in the estimated lives saved and injuries prevented over the service life of a project. This type of information is typically pre- sented in tabular format as shown in Table 79. This example simply repurposes the information from Table 77 where the base condition is an existing urban, two-lane, two-way stop-controlled intersection; Alternative 1 is a traffic signal, and Alternative 2 is a roundabout. As discussed pre- viously, there is a need to convert changes in fatal and injury crashes to changes in fatalities and injuries. For this example, the national average factors of 1.09 fatalities per fatal crash and 1.44 injuries per injury crash are used to convert the crash-based numbers in Table 77 to person- based numbers (NHTSA 2020). Again, rather than presenting the numbers as decimals representing average reductions per year, it may be preferable to report the savings over the service life of the project or some longer analysis period. Also, it is generally preferred to round the values to the nearest whole number when reporting lives saved and injuries prevented. Individually, the results in Table 79 con- sistently show that Alternative 2 provides a greater savings than both Alternative 1 and the existing conditions; however, there is the potential to misinterpret these findings if the focus is on lives saved. For lives saved, both alternatives are expected to save less than 1.0 fatal crash over the analysis period. While the value is larger for Alternative 2, this is not apparent due to the rounding. In this case, it may be prudent to focus on a combination of categories (e.g., fatali- ties and suspected serious injuries) when comparing the alternatives. Figure 130 is an example infographic that shows an alternative way to represent key data for lives saved and injuries prevented from Table 79. Summary This chapter presents several considerations and options for communicating the safety per- formance of access management strategies and alternatives to agency partners, decision-makers, and other stakeholders. The chapter provides a discussion of different audiences (technical and non-technical), communication methods (advisory groups, technical materials, case studies, graphics), safety performance measures (estimated crashes, benefit-cost ratio, and lives saved/ injuries prevented), and formats for presenting results (tabular and graphical). Several examples are provided that illustrate tabular and graphical formats as well as different information that may be appropriate in a summary report. Table 79. Example comparison of lives saved and injuries prevented over 20-year analysis period. Measure 20-year Savings with Alternative 1 Compared to Existing Conditions 20-year Savings with Alternative 2 Compared to Existing Conditions Lives saved <1 <1 Suspected serious injuries prevented 1 8 Suspected minor injuries prevented 1 9 Possible injuries prevented 5 41 Total lives saved and injuries prevented 7 58

Communicating Results 119   There is a wide range of options to communicate the safety performance of access management strategies, including various measures and formats. While the methods in this guide can help to quantify safety performance and identify safety-beneficial alternatives, the effort is futile unless decision-makers use the results to inform decisions. As such, there is a need to clearly and concisely communicate the analysis results to the target audience, regardless of the measure and format selected. Engaging a communication expert in this effort may be appropriate. The key objective is to inform the decision-making process. By quantifying the safety performance of alternatives, decision-makers can compare safety against other competing factors in selecting the preferred alternative and determining if a project justifies the investment. Figure 130. Alternative presentation of data from Table 79.

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Application of Crash Modification Factors for Access Management, Volume 1: Practitioner's Guide Get This Book
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While research and empirical evidence have shown positive safety and operational benefits associated with good access management practices, it can be challenging for transportation agencies to implement access management strategies on the basis of safety performance without methods and tools to quantify the safety performance of alternatives.

The TRB National Cooperative Highway Research Program's NCHRP Research Report 974: Application of Crash Modification Factors for Access Management, Volume 1: Practitioner’s Guide presents methods to help transportation planners, designers, and traffic engineers quantify the safety impacts of access management strategies and make more informed access-related decisions on urban and suburban arterials.

NCHRP Research Report 974: Application of Crash Modification Factors for Access Management, Volume 2: Research Overview documents the research process related to access management features.

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