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38 CHAPTER 4 BENEFIT-COST ANALYSIS OF BICYCLE FACILITIES INTRODUCTION AND PURPOSE Estimates of existing bicycling demand are based on U.S. census journey to work mode shares. Establish the number of Based on the research conducted for this project, the team residents within 400-, 800-, and 1,600-m buffers of the facil- crafted a set of guidelines to be used by transportation pro- ity by multiplying the area of each buffer by a user-supplied fessionals and government agencies to better integrate the population density. Multiply the number of residents in each planning of bicycle facilities into the transportation plan- buffer (R) by 0.4, assuming the national averages of 80% of ning process. The web-based guidelines will assist state residents are adults and 50% of adults are commuters, to cal- DOTs and other state, regional, and local agencies in con- culate the number of daily commuters. Then multiply this sidering bicycling in all transportation projects. Additionally, number of commuters in each buffer by the region's bicycle the guidelines will support local agencies' review of bicycle commute share (C). Use the bicycle commute share for the projects as part of the transportation improvement plan. Metropolitan Statistical Area (MSA) as the default value; the Transportation planners will be able to use the guidelines user has the option to enter a commute share for the specific for the following purposes: area if it is known. Daily existing bicycle commuters = R C 0.4 Estimating the likely cost of specific facilities based on type and on key characteristics, Adult commuters represent only a portion of adult bicy- Estimating how a facility will impact the overall bicycling clists. The team compared U.S. census commute shares to environment in an area, and implicitly how it will affect NHTS data and found that the total adult bicycling rate the amount of riding based on characteristics of the facil- ranges from the census commute rate at the low end to 0.6% ity and of the surrounding area, plus three times the commute rate at the high end (Appen- If information is available for calibration, estimating the dix A). This allows the use of readily available census com- usage of a facility (and the change in usage of comple- mute shares to extrapolate total adult bicycling rates (T). mentary and competing facilities), and Estimating the specific types of benefits and their rela- Thigh = 0.6 + 3C tive sizes based on characteristics of the facility and of the surrounding area. Tmoderate = 0.4 + 1.2C Tlow = C TRANSLATING DEMAND AND BENEFITS RESEARCH INTO GUIDELINES Multiply the estimated low, moderate, and high rates by the number of adults--estimated to be 80% of the population-- Demand in each buffer to arrive at the total number of daily adult cyclists. Estimating the use of a new facility rests on two main assumptions. First, all existing commuter bicyclists near a Total daily existing adult cyclists = Tj R 0.8 8 new facility will shift from some other facility to the new one. Second, the new facility will induce new bicyclists as a Additional research (Appendix B) found that people function of the number of existing bicyclists. Research for who live near a facility are more likely to bike than those this project uncovered that people are more likely to ride a that do not; multipliers were developed to describe these bicycle if they live within 1,600 m (1 mi) of a facility than if probabilities. Multiplying the numbers of both commuters they live outside that distance (Appendix B). The likelihood and total adult cyclists by the likelihood multipliers found of bicycling increases even more at 800 m and 400 m. The in this research for various buffers around the proposed team therefore estimates existing and induced demand using facility provides an estimated number of induced cyclists 400-, 800-, and 1600-m buffers around a facility. in each group.

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39 New commuters = ( Existing commuters ( Ld - 1)) of studies of outdoor recreational activities (Appendix G). From both NHTS and Twin Cities TBI, the average adult d = 400, 800, 1, 600 cycling day includes about 40 min of cycling. This is the amount used, plus some preparation and cleanup time. Mul- New adult cyclists = ( Existing g adult cyclists ( Ld - 1)) tiply this by the number of new cyclists minus the number of d = 400, 800, 1, 600 new commuters. (The value of the facility to new commuters is counted in the mobility benefit.) Where Annual recreation benefit = D 365 L400m = 2.93 L800m = 2.11 ( new cyclists - new commuters ) L1600m = 1.39 Reduced Auto Use Benefits Mobility Benefit These benefits apply only to commuter and other utili- This research, based on stated preference analysis, found tarian travel, because it is assumed that recreational rid- that bicycle commuters are willing to spend, on average 20.38 ing does not replace auto travel. These include reduced extra minutes per trip to travel on an off-street bicycle trail congestion, reduced air pollution, and user cost savings. when the alternative is riding on a street with parked cars (6). Multiply the total benefit per mile by the number of new Commuters are willing to spend 18.02 min (M) for an on- commuters, multiplied by the average round trip length street bicycle lane without parking and 15.83 min for a lane from NHTS (L). with parking. Assuming an hourly value of time (V) of $12, Then consider two offsetting adjustments that ultimately the per-trip benefit is $4.08, $3.60, and $3.17, respectively. leave the total number unchanged. First, there are utilitar- Multiply the per-trip benefit for the appropriate facility by the ian riders in addition to commuters and some of these trips number of daily existing and induced commuters, then dou- will replace auto trips. Second, not all new bike commuters ble it to include trips both to and from work. This results in and utilitarian riders would have made the trip by car; evi- a daily mobility benefit. Multiplying the daily benefit by dence from NHTS suggests that something less than half 50 weeks per year and 5 days per week results in the following of bike commuters use driving as their secondary commuting annual benefit: mode. For simplicity, assume that these two factors offset Annual mobility event = M V 60 each other, and thus the total amount of new bike commuter mileage is a reasonable number to use to represent the total ( existing commuters + new commuters ) 50 5 2 amount of new bike riding substituting for driving. The benefit per mile of replacing auto travel with bicycle It should be noted that this methodology assumes that no travel is a function of location and the time of day. There will bicycle facility previously existed nearby, aside from streets be no congestion-reduction benefits in places or at times with parking. In the this equation, V is divided by 60 because when there is no congestion. Pollution-reduction benefits will the M is in minutes and V is in hours; dividing V by 60 con- be higher in more densely populated areas and lower else- verts it to minutes so that the result can easily be multiplied where. User cost savings will be higher during peak periods by the minutes. when stop-and-go traffic increases the cost of driving. Based on reasoning documented in Appendix G, conges- Health Benefit tion savings will be 0 to 5 cents per mile and pollution sav- ings from 1 to 5 cents per mile depending on conditions. An annual per-capita cost savings from physical activity Assume the high end of this range in central city areas, the of $128 is determined by taking the median value of 10 stud- middle range in suburban areas, and the low end in small ies (Appendix E). Then multiply $128 by the total number of towns and rural areas. For simplicity, assume that all com- new bicyclists to arrive at an annual health benefit. muting and utilitarian trips are during congested periods. User cost savings were determined to be 3 cents per mile dur- Annual health benefit = total new cyclists $12 28 ing congested peak periods and 0 otherwise; thus, these are scaled by location in the same way as congestion savings. Overall, the savings per mile (S) is 13 cents in urban Recreation Benefit areas, 8 cents in suburban areas, and 1 cent in small towns and rural areas. The "typical" day involves about 1 hr of total bicycling activity, which is valued at $10 (D), based on a wide variety Reduced auto use benefit = new commuters L S 50 5