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From page 46... ... 46 Application of Benefit–Cost Analysis for 3R Projects Benefit–cost analysis enables highway agencies to assess design alternatives for 3R projects and decide (a) whether geometric improvements should be made as part of the project and, if so, (b) Read the entire page →
From page 47... ... Application of Benefit–Cost Analysis for 3R Projects 47 3R project benefit–cost analyses. Cost estimates with planning-level accuracy are appropriate for deciding whether to incorporate geometric improvements in a 3R project and what geometric improvements to implement. Read the entire page →
From page 48... ... 48 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Chapter 11) Read the entire page →
From page 49... ... Application of Benefit–Cost Analysis for 3R Projects 49 where Nbr = predicted average crash frequency for an individual roadway segment averaged over the service life of the improvement (including multiple-vehicle nondriveway crashes, single-vehicle crashes, and multiple-vehicle driveway crashes) , Npedr = predicted average crash frequency of vehicle–pedestrian crashes for an individual roadway segment averaged over the service life of the improvement, and Nbiker = predicted average crash frequency of vehicle–bicycle crashes for an individual roadway segment averaged over the service life of the improvement. Read the entire page →
From page 50... ... 50 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects w k N∑ = + 1 1 (39) Read the entire page →
From page 51... ... Application of Benefit–Cost Analysis for 3R Projects 51 CMFjk = crash modification factor for crash severity level k from implementing improvement j, and Nmk = expected annual crash frequency for crash severity level k at site m prior to improvement. Nmk represents the value of Npredicted or Nexpected derived in Section 5.1.3. Read the entire page →
From page 52... ... 52 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects 5.1.6 Service Life of the Improvement Pavement resurfacing typically has a service life of 7 to 12 years, depending on construction and material quality and traffic volume, until resurfacing is needed again. Read the entire page →
From page 53... ... Application of Benefit–Cost Analysis for 3R Projects 53 Safety benefits are annual crash cost savings. To calculate the present value of safety benefits, the annual crash cost savings are multiplied by the uniform series present worth factor: ( ) Read the entire page →
From page 54... ... 54 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects throughout the U.S., these examples might serve as a basis for 3R design policy. Read the entire page →
From page 55... ... Application of Benefit–Cost Analysis for 3R Projects 55 in this example, the equation simplifies to not having a summation. The HSM and data from Table 31 are used to calculate CMFs for use in determining Npredicted ravg. Read the entire page →
From page 56... ... 56 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects ( ) Read the entire page →
From page 57... ... Application of Benefit–Cost Analysis for 3R Projects 57 ( ) Read the entire page →
From page 58... ... 58 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects ( ) Read the entire page →
From page 59... ... Application of Benefit–Cost Analysis for 3R Projects 59 agency regardless of whether the lanes were widened. The present value of the safety benefit, calculated with Equations 71 and 72, results in a value of $56,041. Read the entire page →
From page 60... ... 60 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects This analysis can be repeated to determine minimum traffic volume levels in which lane widening of other intervals becomes economically feasible. Read the entire page →
From page 61... ... Application of Benefit–Cost Analysis for 3R Projects 61 AADT (veh/day) Net Implementation Cost ($) Read the entire page →
From page 62... ... 62 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects benefit–cost analysis is to determine the net benefit (present value of safety benefits minus implementation cost) Read the entire page →
From page 63... ... Application of Benefit–Cost Analysis for 3R Projects 63 less than the net benefit of widening from 10 to 11 ft, and, therefore, the additional increment of investment to widen to 12-ft lanes is not cost-effective. • For a roadway with an AADT of 4,000 veh/day or more, widening from 10 to 12 ft has the highest net benefit in all cases. Read the entire page →
From page 64... ... 64 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects The results of the incremental benefit–cost analyses presented above show that benefit–cost analysis can be used to create guidelines on the minimum AADT levels for which lane widening or other geometric improvements may be cost-effective in 3R projects. Read the entire page →
From page 65... ... Application of Benefit–Cost Analysis for 3R Projects 65 The high values for minimum AADT level for widening from 11 to 12 ft occur because there is relatively little safety benefit in widening lanes from 11 to 12 ft on a rural two-lane highway (see Figure 3) Read the entire page →
From page 66... ... 66 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects 5.5.1 Benefit–Cost Analysis for a Single Design Alternative for a Specific Site A single design alternative for a specific site can be evaluated by using Equation 46 to determine the benefit–cost ratio for the alternative. Read the entire page →
From page 67... ... Application of Benefit–Cost Analysis for 3R Projects 67 AADT guidelines are needed for each facility type and terrain category. All assumptions in the benefit–cost analysis, including implementation costs and crash costs, should be based on the policies and experience of an individual highway agency. Read the entire page →
From page 68... ... 68 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Tool 1 includes logic to estimate the implementation cost of the improvement alternatives evaluated. Read the entire page →
From page 69... ... Application of Benefit–Cost Analysis for 3R Projects 69 • Fatal and injury (FI) crashes per year before the project, • Property-damage-only crashes per year before the project, • FI crashes per year after the project, • Property-damage-only crashes per year after the project, • FI crashes per year reduced by the project, and • Property-damage-only crashes per year reduced by the project. Read the entire page →
From page 70... ... 70 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Tool 2 includes logic to estimate the implementation cost of the improvement alternatives evaluated; the cost estimation logic in Tool 2 is essentially equivalent to the cost estimation logic in Tool 1. Read the entire page →
From page 71... ... Application of Benefit–Cost Analysis for 3R Projects 71 The most cost-effective improvement alternative (or combination of alternatives) identified by Tool 2 is that with the highest net benefit whose implementation cost is within the highway agency's available budget. Read the entire page →
From page 72... ... 72 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Tables 45 and 46 describe the existing geometric design and other existing conditions for the roadway segment. Read the entire page →
From page 73... ... Figure 7. Roadway data input for rural two-lane highway in Example 1A. Read the entire page →
From page 74... ... 74 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects • Figure 9 shows the existing cross-section data from Table 45 that are entered. Read the entire page →
From page 75... ... Application of Benefit–Cost Analysis for 3R Projects 75 Next, Tool 1 is applied to consider lane widening from 10.5 ft to 12 ft on a two-lane highway with the same characteristics as presented in Figures 7 through 12 but with a higher AADT equal to 8,600 veh/day. The only change needed in the input data is that the AADT of 2,000 veh/day in Figure 7 is changed to 8,600 veh/day. Read the entire page →
From page 76... ... 76 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Figure 14. Read the entire page →
From page 77... ... Application of Benefit–Cost Analysis for 3R Projects 77 The screenshot in Figure 17 shows that, even when the AADT of the rural two-lane highway is increased to 8,600 veh/day, the shoulder paving improvement alternative is still not costeffective, since the costs exceed the benefits. On the basis of the results of the benefit–cost analyses in Figures 16 and 17, paving the unpaved shoulder in conjunction with the 3R project is not cost-effective at either of the AADT levels considered. Read the entire page →
From page 78... ... 78 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects The screenshot in Figure 20 shows the Results summary from Tool 1 for assessment of the superelevation improvement for the rural two-lane highway with a higher AADT of 8,600 veh/day. Read the entire page →
From page 79... ... Application of Benefit–Cost Analysis for 3R Projects 79 with an AADT level of 8,600 veh/day. The screenshot in Figure 21 presents the results of this assessment. Read the entire page →
From page 80... ... 80 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects For the first case, the site-specific crash history data indicate fewer crashes than the crash prediction models. Read the entire page →
From page 81... ... Application of Benefit–Cost Analysis for 3R Projects 81 Figure 24. Results of benefit–cost analysis in Example 1C for shoulder paving of rural two-lane highway with AADT of 8,600 veh/day with site-specific crash history data lower than predicted. Read the entire page →
From page 82... ... 82 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects 5.7.1.4 Example 1D: Use of Spreadsheet Tool 2 to Achieve the Same Results as Examples 1A and 1B in One Step Spreadsheet Tool 2 can be used to obtain the same results obtained in Examples 1A and 1B in a single step. Read the entire page →
From page 83... ... Application of Benefit–Cost Analysis for 3R Projects 83 Figures 30 through 34 present screenshots of the data entry windows in Tool 2 showing the data for the rural two-lane highway with an AADT level of 2,000 veh/day. These windows are equivalent to the Tool 1 data entry forms shown in Figures 7 through 11. Read the entire page →
From page 84... ... 84 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Figure 32. Read the entire page →
From page 85... ... Application of Benefit–Cost Analysis for 3R Projects 85 Figure 34. Crash history input in Tool 2 for rural two-lane highway in Example 1D. Read the entire page →
From page 86... ... 86 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects lane width of 10.5 ft, checking "Widen Lane Width" in Figure 35 is equivalent to specifying that lane widths of 10.5, 11.0, 11.5, and 12.0 ft will be considered. Read the entire page →
From page 87... ... Application of Benefit–Cost Analysis for 3R Projects 87 classified on the basis of the net benefit resulting from implementation of the alternative. The table also shows the total cost for each improvement scenario, so that scenarios that exceed the available budget can be eliminated from consideration. Read the entire page →
From page 88... ... 88 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects In Example 2, an agency chooses to develop minimum AADT tables for lane widening on rural two-lane highways by using the assumed set of existing conditions presented in Table 53. Read the entire page →
From page 89... ... Application of Benefit–Cost Analysis for 3R Projects 89 Lane Widening Scenario (ft) Minimum AADT (veh/day) Read the entire page →
From page 90... ... 90 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Proposed Lane Widening Minimum AADT (veh/day) Read the entire page →
From page 91... ... Application of Benefit–Cost Analysis for 3R Projects 91 The screenshots in Figures 36 through 41 show how the project inputs should appear in the spreadsheet-based tool. The results of the benefit–cost analysis are shown in the screenshot in Figure 42. Read the entire page →
From page 92... ... Figure 39. Specific curve data for Example 3. Read the entire page →
From page 93... ... Application of Benefit–Cost Analysis for 3R Projects 93 The results of the analysis with Tool 2 are shown in Table 60. The table shows the 15 improvement alternatives that Tool 2 indicates will produce the highest net benefits. Read the entire page →
From page 94... ... 94 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Variable Measurement/Type Section length 3 mi AADT 45,000 veh/day Terrain Rolling Pavement Flexible Percentage of section length on horizontal curves 15% Typical curve radius 3,250 ft Number of horizontal curves 4 Number of through lanes 4 Lane width 12 ft Outside shoulder width 4 ft Inside shoulder width 2 ft Outside roadside slope 1V:3H Median width 30 ft Median cross slope 1V:6H Presence of median barriers No Presence of outside barriers Yes Clear zone width 20 ft Rumble strips present Inside and outside shoulders Proportion of AADT during hours where volume exceeds 1,000 vph/lane 0 Note: vph = vehicles per hour. Read the entire page →
From page 95... ... Figure 43. Roadway data input for freeway in Example 4. Read the entire page →
From page 96... ... 96 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Figure 48. Read the entire page →
From page 97... ... Application of Benefit–Cost Analysis for 3R Projects 97 Figure 52. Results of benefit–cost analysis for widening of inside and outside shoulders for freeway in Example 4. Read the entire page →

From page 46...

... 46 Application of Benefit–Cost Analysis for 3R Projects Benefit–cost analysis enables highway agencies to assess design alternatives for 3R projects and decide (a) whether geometric improvements should be made as part of the project and, if so, (b)