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C-1 A P P E N D I X C Countermeasure Cost-Effectiveness Summary After individual poles or a series of poles along a corridor are identified as high-risk (either based on utility pole crashes or based on their placement in high-risk locations), the next questions relate to what treatments may be justified. The second phase of the FHWA study by Zegeer and Parker in 1983, discussed earlier in the report, dealt with quantifying the crash effects of various treatment options. The treatments, which were also analyzed in terms of their potential economic feasibility, pertain to modifying the pole itself (e.g., pole relocation). A different set of countermeasures intended to indirectly reduce utility pole crashes by keeping the vehicle on the roadway (e.g., delineation, lighting, advance curve signing) and measures to reduce crash severity (e.g., guardrail or breakaway poles) are discussed later in more detail. The Zegeer and Parker study developed expected crash effects and the cost-effectiveness (i.e., benefit/cost [B/C] ratio) of several utility pole treatments, including: 1. Placing utility lines underground (and removing the poles) 2. Increasing the lateral offset of the poles from the roadway 3. Reducing the number of poles (multiple pole use, increasing pole spacing, or using poles only on one side of the road) 4. Using combinations of increasing lateral pole offset and reducing pole density 5. Using breakaway poles. The B/C ratios for each treatment option were based primarily on three factors: (1) the expected reduction in utility pole crashes (based on the crash prediction model), (2) estimates of countermeasure costs (based on cost estimates from utility companies throughout the U.S.), and (3) the roadside adjustment factor (RAF). The RAF was needed to adjust for the fact that the effect of any utility pole treatment (e.g., pole relocation) must be adjusted based on the presence of trees, steep slopes, and other roadside conditions. For example, when utility poles are moved or removed, the out-of-control vehicle that would have hit the utility pole may instead (1) have no collision at all, (2) hit some other fixed object, or (3) roll over down the side slope. RAFs were determined based on the area type (urban
C-2 Utility Pole Safety and Hazard Evaluation Approaches A summary is given below of the results of the cost-effectiveness analysis for each type of countermeasure and the results from the study by Zegeer and Parker (1983). Note that costs and also crash-related safety benefits (i.e., both the numerator and denominator of the B/C calculation) may be considerably different in todayâs dollars than in 1983. Thus, the B/C ratios given below are primarily meant to illustrate the relative desirability of countermeasure options for various traffic and roadway conditions. More up-to-date calculations of the expected B/C ratio for individual countermeasures can be computed as described in the âSelection of Cost- Effective Countermeasures for Utility Pole AccidentsâUserâs Manualâ Zegeer and Cynecki, December 1986). PLACE UTILITY LINES UNDERGROUND AND REMOVE UTILITY POLES Removing the utility poles altogether and placing the utility lines underground are usually a very costly and labor-intensive treatment. Costs for undergrounding were obtained from 21 different utility companies for the purpose of this study. Costs were found to vary widely, based on the type of utility poles, voltage of the lines, area type, construction methods, and other factors. The costs were summarized separately for (1) transmission lines (greater than 69 kv), (2) distribution lines less than 69 kv with conduit used, (3) distribution lines less than 69 kv with direct burial three-phase line, (4) less than 69 kv, direct burial, one-phase lines, and (5) telephone lines. The B/C analysis found that it was generally not cost-effective to underground utility lines for transmission lines, electric lines requiring conduits, and three-phase electric lines because of the high costs related to these countermeasures. However, placing telephone lines underground (which is much less expensive than undergrounding large electric lines) was found to have B/C ratios greater than 1.0 for many situations and lines, as shown in Table C1. or rural), distance of the poles from the roadway (between 2 feet and 30 feet from the road), and the 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, and RAFs were expressed based on the coverage of the roadside by other fixed objects and steep slopes (from 1 to 100% coverage of other fixed objects). See the full FHWA report for details of the B/C process (Zegeer and Parker. 1983. âCost-Effectiveness of Countermeasures for Utility Pole Accidents.â Washington, DC: FHWA, U.S. Department of Transportation, January).
Countermeasure Cost-Effectiveness Summary C-3 TABLE C1: SUMMARY OF BENEFIT/COST RATIOS FOR UNDERGROUNDING TELEPHONE LINES IN URBAN AREAS
C-4 Utility Pole Safety and Hazard Evaluation Approaches TABLE C2: MINIMUM ANNUAL NUMBER OF UTILITY POLE CRASHES REQUIRED PER MILE FOR UNDERGROUNDING This is particularly true for situations where the telephone poles are currently within 5 feet of the roadway and the traffic volume exceeds 5,000 vehicles per day (vpd), with a relatively clear and level roadside. Consider undergrounding telephone lines in an urban area, for example, where the pole offset is 5 feet, with 50 poles per mile, an AADT of 20,000, and a relatively flat roadside free of other fixed objects. By going to the first column in Table C1with a pole offset of 5 feet, reading down to an ADT of 20,000, and 50 poles per mile in the âclear level roadsideâ column, the table shows a B/C ratio of 2.01. The minimum number of crashes required in order for undergrounding to be cost-effective is given in Table C2. RELOCATE UTILITY POLES FURTHER FROM THE ROADWAY This countermeasure involves removing all poles from their current location and installing them further from the roadway. Here, 10 telephone and 31 electric companies provided costs for pole relocation. Costs were summarized in the report separately for: ⢠Wood power poles carrying less than 69 kv ⢠Non-wood (metal, concrete, or other) poles ⢠Steel transmission poles and towers. In terms of the cost-effectiveness of pole relocation, the greatest B/C ratios occur in situations where the polesâ average distance from the roadway can be relocated to at least 10 feet from
Countermeasure Cost-Effectiveness Summary C-5 the road in the after condition. Also, relocating telephone poles is generally more cost-effective than relocating electric poles due to the considerably lower cost for moving telephone poles. Table C3 provides B/C ratios for relocating telephone poles for various pole offset distances for various traffic volumes and pole densities. Note that Table C3 has assumed a 35% roadside coverage factor for all values. To illustrate the use of Table C3, assume that telephone poles are currently located an average of 2 feet from the roadway with an ADT of 10,000 and a density of 30 poles per mile on a road with 35% coverage of other roadside objects. Relocating the poles back to 20 feet (see the first row) from the road would result in an estimated B/C ratio of 3.44. Notice that the B/C ratio would be less than 3.44 for similar situations with more than 30 poles per mile. This is due to the added cost of relocating the additional poles.
C-6 Utility Pole Safety and Hazard Evaluation Approaches REDUCE POLE DENSITY Reducing utility pole density can include three different types of strategies: (1) increasing the spacing between poles, (2) using a line of poles for multiple purposes (e.g., to carry electric and telephone lines together), and (3) using one line of poles instead of two lines. Increasing pole spacing may require the use of larger stronger poles to carry the heavier loads since pole spacing is computed based on structural considerations. Of course, having larger sturdier poles might result in more severe crash outcomes when struck by motor vehicles. Regarding cost- effectiveness considerations, the cost of increasing pole spacing from an existing line of poles can be comparable to the cost of pole relocation. TABLE C3: SUMMARY OF BENEFIT/COST RATIOS FOR RELOCATING TELEPHONE POLES AND LINES IN RURAL AREAS (ASSUMES A 35% ROADSIDE COVERAGE FACTOR)
Countermeasure Cost-Effectiveness Summary C-7 Multiple pole use, or doubling up the types of utility lines carried by the same poles, has been a common practice by utility companies for many years. This includes having electric, telephone, cable, television, and 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 relocating the poles. Converting from two lines of poles to one line generally requires eliminating poles from the side of the road where poles are closest to vehicle travel. There are some situations where a double line of poles exists on the same side of the road, carrying different types of utility lines. In this situation, reducing pole density would involve removing the line of poles closest to the road and doubling utility lines on the other poles. The utility pole crash prediction model was also used to calculate the safety benefit of having fewer poles per mile for various roadway conditions, whether it is increasing pole spacing (for poles on one side of the road) or whether the treatment is multiple pole use (where poles on one side of the road are removed and utility lines are doubled up on the other side of the road). The B/C ratios were generally found to be below 1.0 for most examples involving increasing pole spacing since this would incur the cost of basically moving every pole, which would have only a minimal safety benefit from only a small reduction in the number of poles. However, multiple pole use was found to be generally cost-effective for many situations. For example, Table C4 shows higher B/C ratios for situations with a greater number of poles per mile and lower pole offset. Consider, for example, a situation with poles on both sides of the road that average 2 feet away, with 50 poles per mile on a flat roadside clear of most other obstacles. By removing poles on one side and doubling lines on poles on the other side, the B/C ratio would be expected to be approximately 3.52, as shown in Table C4. The minimum number of crashes that is required in order for multiple pole use to be cost-effective is given in Table C5.
C-8 Utility Pole Safety and Hazard Evaluation Approaches TABLE C4: SUMMARY OF BENEFIT/COST RATIOS FOR MULTIPLE POLE USE TABLE C5: SUMMARY OF THE MINIMUM NUMBER OF UTILITY POLE CRASHES TO ENSURE COST-EFFECTIVENESS OF MULTIPLE POLE USE IN URBAN AREAS COMBINE REDUCTION IN POLE DENSITY AND POLE RELOCATION FURTHER FROM THE ROAD This treatment is less common since it not only requires space to move the pole further from the road but also means that the utility owner must decide to use more structurally strong poles in order to handle the added weights per pole of having increased spacing. Costs for this measure
Countermeasure Cost-Effectiveness Summary C-9 were calculated based on costs obtained from numerous utility company owners for various pole treatment situations. 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 hardware to the pole to allow it to break away when impacted by an errant vehicle, resulting in slower deceleration and less severe outcomes for the vehicle occupants. The use of these pole features was initiated several decades ago in four states on a trial basis but has not gained widespread acceptance yet. At the time of their introduction in the 1980s, the cost of converting to steel-reinforced features cost around $1,000 per pole, but costs are likely higher now. The cost-effectiveness of the steel-reinforced safety pole is more difficult to determine because of limited information about the relative reduction in crash severity that would be expected due to converting selected poles from a wood base to a steel-reinforced breakaway base. For the Zegeer and Parker 1983 study for FHWA, an estimated B/C ratio was computed with two different assumptions, that this treatment would reduce the injury and fatal crashes by 30% and by 60%. Under the 30% assumption, this pole treatment was primarily cost-effective (i.e., B/C greater than 1.0) for roads with ADTs above 20,000 and with pole offsets of 2 feet and fewer than 60 poles per mile. If this pole treatment results in a 60% reduction in injuries and fatal pole crashes, it would be cost-effective under a wide variety of roadway situations for ADTs as low as 5,000, with any pole offsets, and even for some poles that are 10 or 15 feet from the road, as shown in Table C6. Note that the pilot study of the steel-reinforced poles in four states did show that they were highly effective in producing a much less severe outcome for any strikes that did occur to poles having this safety feature.
C-10 Utility Pole Safety and Hazard Evaluation Approaches TABLE C6: SUMMARY OF BENEFIT/COST RATIOS FOR BREAKAWAY POLES (ASSUMING A 30% AND 60% REDUCTION IN INJURIES AND FATAL CRASHES) COUNTERMEASURE COST-EFFECTIVENESS The analysis results from the 1983 FHWA Zegeer and Parker study were compiled into a format that allows a user to quickly determine what countermeasures are generally cost-effective for a given set of site-specific conditions. Such guidelines might also be useful in selecting countermeasures that are to be more formally evaluated later. The guidelines contained in this discussion are intended for urban, suburban, and rural divided and undivided roadways. The results do not apply to freeways or other full-access controlled highways. The following guidelines are intended to help the user review a utility pole safety problem and then select the candidate countermeasures that are most likely to be cost-effective. It should be remembered that the B/C values are based on an average set of conditions in terms of utility pole types, pole placement and density, traffic ADT, and condition of the roadside where the utility poles are located. Therefore, a more detailed site-specific analysis is
Countermeasure Cost-Effectiveness Summary C-11 recommended prior to the final selection of a countermeasure, and the Utility Pole User Guide allows for such a more refined cost-effective analysis to select the optimal solution for a given roadway and utility pole situation. SELECTION OF COST-EFFECTIVE COUNTERMEASURES Based on the calculation of B/C ratios for the utility pole treatments discussed above, the Zegeer and Parker study developed a series of tables that provide an overview of which countermeasures are generally cost-effective (i.e., have a B/C cost ratio of 1.0 or above) for various combinations of traffic and roadway features. These guidelines described below are for 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, pole offsets of 2 feet to 20 feet, pole densities from 0 to more than 60 poles per mile, and a variety of roadside conditions. These guidelines are intended to assist the user in identifying which countermeasure options are likely to be cost-effective. To illustrate how these guidelines were displayed, Table C7 corresponds to cost-effective countermeasures for telephone poles that are present along urban streets. A series of matrix cells is provided that contains letters for some cells corresponding to countermeasures that are cost- effective. Cells were created consisting of various combinations of pole offset distance, pole density, ADT, and roadside coverage of other fixed objects. The letters in the matrix cells correspond to various countermeasures, such as underground lines (U), relocation of utility poles further from the road (R), multiple pole use (M), and breakaway (steel-reinforced safety poles) poles (B). A circled letter is defined as a different location distance (circled R) or an assumed reduction in severity from the installation of a breakaway device (circled B). An empty matrix cell means that none of those countermeasures is generally cost-effective for the given combination of conditions. A quick review of Table C7 reveals that most of the matrix cells in the upper and right-hand corner of Table C7 contain several symbols. This is because poles are close to the roadway with high vehicle volumes in this part of the table, and, therefore, there is a high likelihood for numerous possible cost-effective solutions for these roadway situations. Notice that situations in the lower portion of the table typically have few or no symbols in those cells, meaning that none of the listed countermeasures is generally cost-effective since the poles are already further from the road. Also, the columns that represent flat roadsides with no other fixed objects have more cost-effective treatments (i.e., more symbols in the matrix cells), compared to similar roadways with higher coverage (up to 60%) of fixed objects. This is because the clear flat roadsides will have fewer crashes involving trees or other objects after moving or removing the poles by pole relocation or undergrounding, for example. Consider, for example, a roadway section that has 65 poles per mile, located an average of 2 feet from the road with an ADT of 30,000 and 35% coverage of roadside obstacles. The cell
C-12 Utility Pole Safety and Hazard Evaluation Approaches corresponding to this set of conditions would have several cost-effective countermeasures, including relocation of poles to 10 feet (assuming adequate right-of-way exists and there is a circled R), breakaway poles (B), undergrounding (U), or multiple pole use (M). To determine which of these treatments is optimal for this set of conditions, a more formal analysis is needed where more specific site conditions are used. A similar roadway having the poles at an average of 20 feet from the road would have none of these countermeasures as cost-effective, i.e., there are no symbols in any of those cells in the lower part of that table. Table C8 provides a similar overview of which countermeasures are cost-effective for telephone poles, except that it pertains to rural instead of urban areas. ADT categories range from 1,000 to 20,000 vehicles per day in Table C8, compared to ADT ranges of 1,000 to 60,000 in Table C7, which reflects lower vehicle volumes in rural areas. Note that Table C7 and Table C8 only involve countermeasures for telephone poles. Similar tables are given for larger poles that carry one-phase and electric distribution lines in Table C9 and Table C10 and for three-phase electric distribution lines in Table C11 and Table C12. No separate chart was provided for transmission TABLE C7: GUIDELINES FOR COST-EFFECTIVE COUNTERMEASURES FOR UTILITY POLE CRASHES: TELEPHONE LINES AND POLES IN URBAN AREAS
Countermeasure Cost-Effectiveness Summary C-13 poles/towers since none of these treatments was cost-effective due to the extremely high cost of moving these poles and/or the high cost of undergrounding the power lines. TABLE C8: GUIDELINES FOR COST-EFFECTIVE COUNTERMEASURES FOR UTILITY POLE CRASHES: TELEPHONE LINES AND POLES IN RURAL AREAS It should be noted that the information in Tables C9 through Table C12 provides general guidelines on which of the countermeasures are cost-effective for a given combination of site conditions, using average countermeasure costs obtained from dozens of utility companies across the nation. Also, the average or expected utility pole crash experience was used, as determined in the crash modeling analysis from the four states. To obtain a more precise assessment of the B/C ratios of countermeasures being considered for a given roadway situation, it is important to use the latest costs for motor vehicle crashes as well as the crash effects discussed earlier. Note that these tables do not include countermeasures such as installing guardrails or crash cushions. Such barriers and other devices may be the preferred solution for numerous roadway and utility pole situations, particularly where the poles are in high-risk locations but cannot be moved for whatever reason.
C-14 Utility Pole Safety and Hazard Evaluation Approaches TABLE C9: GUIDELINES FOR COST-EFFECTIVE COUNTERMEASURES FOR UTILITY POLE CRASHES: ONE-PHASE ELECTRIC DISTRIBUTION LINES (< 69 kV) IN URBAN AREAS
Countermeasure Cost-Effectiveness Summary C-15 TABLE C10: GUIDELINES FOR COST-EFFECTIVE COUNTERMEASURES FOR UTILITY POLE CRASHES: ONE-PHASE ELECTRIC DISTRIBUTION LINES (< 69 kV) IN RURAL AREAS
C-16 Utility Pole Safety and Hazard Evaluation Approaches TABLE C11: GUIDELINES FOR COST-EFFECTIVE COUNTERMEASURES FOR UTILITY POLE CRASHES: THREE-PHASE ELECTRIC DISTRIBUTION LINES (<69 kV) IN URBAN AREAS
Countermeasure Cost-Effectiveness Summary C-17 TABLE C12: GUIDELINES FOR COST-EFFECTIVE COUNTERMEASURES FOR UTILITY POLE CRASHES: THREE-PHASE ELECTRIC DISTRIBUTION LINES (< 69 kV) IN RURAL AREAS
