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Utility Pole Safety and Hazard Evaluation Approaches (2020)

Chapter: Chapter 6 - Countermeasure Cost-Effectiveness

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Suggested Citation:"Chapter 6 - Countermeasure Cost-Effectiveness." National Academies of Sciences, Engineering, and Medicine. 2020. Utility Pole Safety and Hazard Evaluation Approaches. Washington, DC: The National Academies Press. doi: 10.17226/25923.
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Suggested Citation:"Chapter 6 - Countermeasure Cost-Effectiveness." National Academies of Sciences, Engineering, and Medicine. 2020. Utility Pole Safety and Hazard Evaluation Approaches. Washington, DC: The National Academies Press. doi: 10.17226/25923.
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Suggested Citation:"Chapter 6 - Countermeasure Cost-Effectiveness." National Academies of Sciences, Engineering, and Medicine. 2020. Utility Pole Safety and Hazard Evaluation Approaches. Washington, DC: The National Academies Press. doi: 10.17226/25923.
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Suggested Citation:"Chapter 6 - Countermeasure Cost-Effectiveness." National Academies of Sciences, Engineering, and Medicine. 2020. Utility Pole Safety and Hazard Evaluation Approaches. Washington, DC: The National Academies Press. doi: 10.17226/25923.
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Page 41
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Suggested Citation:"Chapter 6 - Countermeasure Cost-Effectiveness." National Academies of Sciences, Engineering, and Medicine. 2020. Utility Pole Safety and Hazard Evaluation Approaches. Washington, DC: The National Academies Press. doi: 10.17226/25923.
×
Page 42
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Suggested Citation:"Chapter 6 - Countermeasure Cost-Effectiveness." National Academies of Sciences, Engineering, and Medicine. 2020. Utility Pole Safety and Hazard Evaluation Approaches. Washington, DC: The National Academies Press. doi: 10.17226/25923.
×
Page 43
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Suggested Citation:"Chapter 6 - Countermeasure Cost-Effectiveness." National Academies of Sciences, Engineering, and Medicine. 2020. Utility Pole Safety and Hazard Evaluation Approaches. Washington, DC: The National Academies Press. doi: 10.17226/25923.
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Page 44

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38 After individual poles (or a series of poles) along a corridor are identified as high risk based on either utility pole crashes or on pole placement in high-risk locations, the next questions relate to the treatments that may be justified. The second phase of the FHWA study by Zegeer and Parker (1983) addressed quantifying the effects of various treatment options on crash rates. These options, which they also analyzed in terms of potential economic feasibility, pertain to modi- fying the pole itself (e.g., pole relocation). A different set of countermeasures is discussed later in more detail: those intended to indirectly reduce the number of utility pole crashes by keeping the vehicle on the roadway (e.g., using delineation, lighting, in-advance curve signing) and by applying measures to decrease crash severity (e.g., installing guardrails or breakaway poles). The Zegeer and Parker (1983) study developed expected crash effects and the cost-effectiveness (i.e., the benefit-cost ratio) of several utility pole treatments, including: • Placing utility lines underground (and removing the poles) • Increasing the lateral offset of the poles from the roadway • Reducing the number of poles (by employing poles for multiple uses, increasing pole spacing, or using poles only on one side of the road) • Implementing combinations of increasing lateral pole offset and reducing pole density • Using breakaway poles. The benefit-cost ratios for each treatment option were based primarily on three factors: (1) the expected reduction in number of utility pole crashes (based on the crash-prediction model), (2) estimates of countermeasure costs (based on cost estimates from utility companies throughout the United States), and (3) the roadside adjustment factor (RAF). The calculation of RAF was needed to adjust for the effect of any utility pole countermeasure (e.g., pole relocation) based on the presence of trees, steep slopes, and other roadside conditions. For example, when utility poles are repositioned or removed, an out-of-control vehicle that typi- cally would hit the utility pole may instead (1) avoid a collision entirely, (2) strike some other fixed object, or (3) roll over (or down) the side slope. RAFs were projected based on the area type (urban or rural), distance of poles from the roadway (ranging from 2 feet to 30 feet from the road), and coverage of other types of fixed objects (between 0% and 100%). A series of RAFs from 0 to 1.0 was developed to account for a wide range of roadside conditions. The full FHWA report (Zegeer and Parker 1983) provides full details on the benefit-cost process. This chapter summarizes cost-effectiveness analysis results for each type of countermeasure and the associated outcomes. Appendix C includes cost-effectiveness analysis tables taken from the full FHWA study (Zegeer and Parker 1983). Note that the dollar value of both costs and crash-related safety benefits (i.e., both the numerator and denominator of the benefit-cost calculation) would be considerably greater today than in 1983. Thus, the benefit-cost ratios shown in Appendix C and cited below are primarily intended to illustrate the relative desirability of C H A P T E R 6 Countermeasure Cost-Effectiveness

Countermeasure Cost-Effectiveness 39 countermeasure options under various traffic and roadway conditions. More updated calcula- tions of the expected benefit-cost ratios for individual countermeasures can be computed as described in the FHWA’s Selection of Cost-Effective Countermeasures for Utility Pole Accidents— User’s Manual (Zegeer and Cynecki 1986). Place Utility Lines Underground and Remove Utility Poles Removing utility poles altogether and burying the utility lines underground are usually very costly and labor-intensive treatments. For the Zegeer and Parker (1983) report, the costs for installing underground cables were obtained from 21 different utility companies. Such expenses varied widely based on the type of utility poles, voltage of the lines, area type, construction methods, and other factors (e.g., local wages, local material costs, project location). The costs were summarized separately for (1) transmission lines (more than 69 kV), (2) distribution lines of less than 69 kV using conduit, (3) distribution lines of less than 69 kV with a direct bury three-phase line, (4) direct bury one-phase distribution lines of less than 69 kV, and (5) telephone lines. Based on the benefit-cost analysis, it was generally not cost-effective to shift to underground utility lines for transmission lines, electric lines requiring conduits, or three-phase electric lines because of the high costs associated with these countermeasures. However, placing telephone lines underground (which is much less expensive than running large electric lines underground) produced benefit-cost ratios of more than 1.0 for many circumstances—particularly when the telephone poles were at that time within 5 feet of the roadway and the traffic volume exceeded 5,000 vehicles per day, with a relatively clear and level roadside. Relocate Utility Poles Further from the Roadway This countermeasure focuses on removing all poles currently in a segment and reinstalling them further from the roadway. In the survey of utility companies for the Zegeer and Parker (1983) report, 10 telephone companies and 31 electric companies supplied costs for pole reloca- tion. Such costs were summarized separately as follows: • Wood power poles carrying less than 69 kV • Nonwood (metal, concrete, or other) poles • Steel transmission poles and towers. In terms of the cost-effectiveness of pole relocation, the greatest benefit-cost ratios result where the average pole distance from the roadway can be at least 10 feet after treatment. Also, relocating telephone poles is generally more cost-effective than repositioning electric poles because of the considerably lower cost of moving telephone poles, which are typically much smaller and lighter than most electric poles (Zegeer and Cynecki 1984). For example, if 30 telephone poles are currently located an average of 2 feet from the roadway with an ADT of 10,000 vehicles on a road with 35% coverage of other roadside objects, relocating the poles to 20 feet from the road would produce an estimated benefit-cost ratio of 3.44. (Of course, the benefit-cost ratio would be less than 3.44 for similar situations with more than 30 poles per mile because of the increased costs for relocating the additional poles.) Reduce Pole Density Efforts to reduce utility pole density can include three different types of strategies: (1) increasing the spacing between poles, (2) using a pole line for multiple purposes (e.g., to carry both electric and telephone lines), and (3) employing one line of poles instead of two pole lines. Increasing

40 Utility Pole Safety and Hazard Evaluation Approaches pole spacing may require the use of larger and stronger poles to carry the heavier loads placed on each individual pole. Of course, when struck by motor vehicles, such larger and sturdier poles might result in more severe crash outcomes. Regarding cost-effectiveness, the cost of increasing pole spacing as a treatment for an existing line of poles can be comparable to the cost of pole relocation (Zegeer and Cynecki 1984). Shared-use utility poles (with multiple utility features on a single line of poles) have been a common utility company practice for many years. This approach includes using each pole to carry some combination of electric, telephone, cable, television, or other communication services (in addition to supporting luminaires along highway rights-of-way) in an effort to decrease distribution costs. The costs for implementing changes in pole density depend on the configuration of the utility poles and lines and on the ease of repositioning the poles. Converting from two lines of poles to one line generally requires eliminating poles from the side of the road where the poles are closest to vehicle travel. In some situations, with a double line of poles on the same side of the road, each pole line carries different types of utility lines. In this circumstance, reducing pole density would involve removing the line of poles closest to the road and then doubling up utility lines on the other poles. The utility pole crash-prediction model was also applied to calculate the safety benefit of fewer poles per mile under various roadway conditions, whether the treatment is increasing pole spacing (for poles on one side of the road) or employing multiple-use poles (where poles on one side of the road are removed and utility lines are doubled up on the other side of the road). The benefit-cost ratios were generally lower than 1.0 for most examples of increasing pole spacing because the cost incurred is basically the expense of moving every pole, which would generate only a minimal safety benefit from marginally fewer poles. However, multiple-use poles were generally cost-effective in many situations because their use usually involves removing all poles on one side of the road and doubling lines on the remaining poles on the other side of the road. This approach often eliminates about half of the total poles without any new pole installa- tions, thus producing greater safety benefits and lower costs compared to increasing the spacing between all poles. Combine Reducing Pole Density and Relocating Poles Further from the Road A combined treatment is less common because it not only requires space to move the pole further from the road but also asks the UO to use structurally stronger poles to handle the added weight per pole that characterizes increased spacing. The costs for this combined countermeasure were calculated based on cost figures obtained from numerous UOs for various pole treatment situations. In some circumstances, the combined treatment was cost-effective, particularly where the telephone poles originally were within approximately 5 feet of the roadway but could be moved at least 10 or 15 feet from the road (with no additional cost for purchasing right-of-way). Convert to Steel-Reinforced Safety (Breakaway) Poles This countermeasure involves modifying selected poles that are in high-risk locations (e.g., very close to the road on the outside of a horizontal curve) by incorporating steel-reinforcement hardware to the pole in two places, enabling it to break away when impacted by an errant vehicle. This breakaway feature more gradually decelerates a vehicle and thus results in a less severe impact for the vehicle and its occupants (when compared to regular wood or steel poles). Several decades ago, five states (Kentucky, Massachusetts, Texas, Virginia, and Maryland) initiated the use of such breakaway pole features on a trial basis, and they are currently employed by a few

Countermeasure Cost-Effectiveness 41 states (as shown in the results of the STA survey). The cost of converting to steel-reinforced features at the time of their introduction in the 1980s was around $1,000 per pole but likely is higher now. The cost-effectiveness calculation for steel-reinforced safety poles is more difficult than that for other pole treatments because of limited information about the relative reduction in crash severity to be expected after converting selected poles from a wood base to a steel-reinforced breakaway base. Zegeer and Parker (1983), in their study for FHWA, computed the estimated benefit-cost ratio based on two different assumptions regarding effectiveness in reducing the number of crashes. These assumptions are calculated as follows: if the poles are not moved, this steel-reinforced pole treatment would not change crash frequency but could reduce the number of crashes resulting in injuries and fatalities by an assumed 30% or 60%. Under the 30% decrease (the first assumption), this pole treatment was primarily cost-effective (i.e., with a benefit-cost ratio exceeding 1.0) for roads with ADT rates higher than 20,000 vehicles, pole offsets of 2 feet or less, and fewer than 60 poles per mile. If the same pole treatment produced a 60% reduction in pole crashes associated with injuries and fatalities (the second assumption), it would be cost-effective under a wide variety of road- way situations—ADT rates as low as 5,000 vehicles, a broad range of pole offsets, and even some poles that originally were 10 or 15 feet from the road. The pilot study of steel-reinforced poles in five states did demonstrate that such poles were highly effective in terms of a much-reduced severity of outcomes for the pole strikes that did occur. Assess Countermeasure Cost-Effectiveness Notably, the benefit-cost values are based on an average set of conditions in terms of utility pole types, pole placement and density, ADT, and condition of the roadside where the utility poles are located. Therefore, a more detailed site-specific analysis is recommended before the final selection of a countermeasure, and the utility pole user’s manual (Zegeer and Cynecki 1986) allows for such a more refined cost-effective analysis to select the optimal solution for a given roadway and utility pole circumstances. Select Cost-Effective Countermeasures On the basis of the calculated benefit-cost ratios for the utility pole treatments discussed above, Zegeer and Cynecki (1986) developed a series of tables in their study for FHWA, giving an overview of the countermeasures that are generally cost-effective (i.e., those with a benefit- cost ratio of 1.0 or higher) for various combinations of traffic conditions and roadway features. These guidelines, described in more detail below, apply to urban, suburban, and rural roadways on divided and undivided roadways, but they do not pertain to freeways. The guidelines include roadways with vehicle ADTs between 1,000 and 60,000 vehicles, pole offsets of 2 feet to 30 feet, pole densities from 0 to 60 poles per mile, and other various roadside conditions. These guide- lines are intended to assist the user in identifying the countermeasure options that are likely to be cost-effective (Zegeer and Cynecki 1984). To illustrate how these guidelines were displayed, Table 8 corresponds to cost-effective counter- measures for utility poles with one-phase electric distribution lines (less than 69 kV) along urban streets. Matrix cells were created, consisting of various combinations of pole offset distances, pole densities, ADT figures, and roadside coverage of other fixed objects. The matrix cells in Table 8 contain letters that correspond to cost-effective countermeasures such as underground utility runs (U), relocation of utility poles further from the road (R),

42 Utility Pole Safety and Hazard Evaluation Approaches multiple-use poles (M), and breakaway poles (steel-reinforced safety poles) (B). Some matrix cells also show circled letters (an R or a B). A circled R is defined as a pole relocation that results in a 10-foot distance from the road, compared to a 20-foot distance for an uncircled R. A circled B indicates an assumed 30% reduction in injuries and fatal crashes after the installation of a breakaway device, compared to the assumed 60% decline in injuries and fatal crashes for an uncircled B. An empty matrix cell indicates that none of those countermeasures is generally cost-effective for the given combination of conditions. A quick review of Table 8 reveals that most of the matrix cells in the upper right corner contain several symbols because, in this part of the table, poles are close to the roadway, with high vehicle volumes. Therefore, there is a high likelihood of utility pole crashes—as well as numerous possible cost-effective solutions for these roadway situations. The cells in the lower portion of the table typi- cally display few or no symbols, which means that none of the listed countermeasures is generally cost-effective (because the poles already were moved further from the road). Also, in Table 8, the columns that represent a flat roadside with no other fixed objects exhibit more cost-effective treatments (i.e., more symbols in the matrix cell) when compared to similar roadways with higher (up to 60%) coverage of fixed objects. This pattern results because clear and flat roadsides will experience fewer crashes involving trees or other objects after moving or removing the poles (e.g., through pole relocation or newly run underground utilities). Consider, for example, a roadway section with 65 poles per mile, each pole located an average of 2 feet from the road; an ADT of 30,000 vehicles; and 35% coverage of roadside obstacles. The Table 8. Illustration of cost-effective countermeasures: one-phase distribution lines in urban areas with various site and utility pole conditions (Zegeer and Parker 1983).

Countermeasure Cost-Effectiveness 43 cell corresponding to this set of conditions shows several cost-effective countermeasures, including relocation of poles to 10 feet from the road (assuming that adequate right-of-way exists and that an R is circled), breakaway poles (B), and underground utility lines (U). To determine which of these treatments is optimal for this set of conditions, a more formal analysis is required, using more specific site conditions. A similar roadway with the poles at an average of 20 feet from the road would show none of these countermeasures as cost-effective (i.e., no symbols in any of those cells in the lower part of the table). If the poles in the preceding example were telephone poles (i.e., smaller and less costly to relocate or move underground), any of these countermeasures for treating the poles would produce higher benefit-cost ratios than those for poles carrying electric lines. In addition, the corresponding table for telephone poles in urban areas would display symbols (i.e., cost-effective options) for more situations than in rural areas (Table 9) as a result of the lower treatment costs (Appendix C). Table 9 provides a similar overview of cost-effectiveness countermeasures for Table 9. Illustration of cost-effective countermeasures: telephone poles in rural areas with various site and utility pole conditions (Zegeer and Parker 1983).

44 Utility Pole Safety and Hazard Evaluation Approaches rural telephone poles instead of larger poles carrying electric lines. Traffic volume categories are lower in Table 9 than in Table 8; i.e., the ADT categories in Table 9 range from 1,000 to 20,000 vehicles per day, compared to an ADT of 1,000 to 60,000 vehicles in Table 8, reflecting lower vehicle volumes for rural roads versus urban roads. Similar tables are included in Appendix C for larger poles that carry one-phase and three-phase electric distribution lines. No separate chart is provided for transmission poles (transmission towers) because none of the treatments were cost-effective as a result of the extremely high cost of relocating such poles (more than $1 million per pole) or transferring the power lines underground. Notably, the information in Table 8 and Table 9 is based on general guidelines regarding cost- effective countermeasures for a given combination of site conditions, relying on average treat- ment cost figures obtained from dozens of utility companies across the nation. Furthermore, this research on cost information (i.e., crash costs and countermeasure outlays) used for these analyses were developed for FHWA in the 1980s by Zegeer and Parker (1983), and no study since then has recalculated crash-reduction factors or cost-effectiveness tables and charts incor- porating more current cost information. Therefore, the charts and tables presented here (and in Appendix C) are primarily designed to give a sense of what types of countermeasures are likely to be worthy of further consideration. To obtain a more precise assessment of benefit-cost ratios for the countermeasures considered for a given roadway situation, it is important to use the more detailed cost-effectiveness analysis in the FHWA user’s manual produced by Zegeer and Cynecki (1986). Neither Table 8 nor Table 9 includes countermeasures such as installing a guardrail or adding reflective bands on poles. As noted previously, for any discussion of cost-effectiveness in this report, the cost of crashes and countermeasure expenditures have increased since Zegeer and Parker (1983) conducted the referenced study, so their data should be applied with caution. Therefore, to compute more up-to-date benefit-cost ratios for various utility pole treatments, the same CMF values noted in this report could be used, but with more updated costs for crashes and pole treatments for a given roadway situation. However, researchers would need to obtain newer countermeasure costs from the utility company that owns and maintains the poles under consideration for a safety improvement. Of course, more up-to-date crash costs also are available from FHWA for use in a benefit-cost analysis. Specifically, the economic assessment of a given countermeasure, such as a treatment involving utility poles, requires knowledge of the cost of a traffic crash at various severity levels (e.g., PDO, injuries, fatalities). More recently, Harmon, Bahar, and Gross (2018) provided infor- mation on crash costs for analyzing highway safety. A thorough benefit-cost analysis also requires input on the interest rate, effectiveness of the countermeasure (CMF), and cost of the treatment. Expenditures for a specified countermeasure (e.g., pole relocation) should be obtained from the relevant STA or UO and should be based on the previous cost of implementing similar treatments under local conditions.

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In 2017, the latest year for which data are available, 887 fatal utility pole crashes occurred in the United States, accounting for 914 fatalities. These numbers were about the same as those in recent years but lower than such fatality numbers from a decade or two ago.

The TRB National Cooperative Highway Research Program's NCHRP Synthesis 557: Utility Pole Safety and Hazard Evaluation Approaches summarizes the strategies, policies, and technologies that state transportation agencies (STAs) and utility owners (UOs) employ to address utility pole safety concerns.

Specific areas of interest for this synthesis report include methods to identify problem poles and high-risk locations, pole-placement policies, strategies and countermeasures to reduce the risk of pole-related collisions and resulting injuries and deaths, and available funding sources for implementing countermeasures. Case studies were also developed for exemplary STAs and UOs, highlighting some of their utility pole safety activities.

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