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3Solutions Don L. Ivey and C. Paul Scott The documented inï¬uence of utility poles on safety makes planning for the accom-modation of utilities early in the design process of critical importance. That sameinï¬uence makes the inclusion of utility poles in every stateâs roadside safety pro- gram as well as the inclusion of an intraorganization roadside safety program in every utilityâs safety program of critical importance. In this chapter, the many practical solutions available for utility companies (utilities), state departments of transportation (DOTs), and local highway agencies (HAs) to accommodate these objectives are described. The most desirable design solution, in terms of roadside safety, is to use as few poles as is practical and to locate the utility poles where they are least likely to be struck by a vehicle. The Roadside Design Guide (1) contains the following options for the location and design of utilities: 1. Increase lateral pole offset. 2. Increase pole spacing. 3. Combine pole usage with multiple utilities. 4. Bury electric and telephone lines underground. A comprehensive group of solutions and countermeasures for extant facilities was recently proposed by Horne (2). These included the following: â¢ Keep vehicles on the roadway: âUse pavement markings, âUse delineators, âImprove skid resistance and drainage, âWiden lanes, âWiden and pave shoulders, and âStraighten curves. â¢ Change pole position or remove: âMove selected poles, âDecrease number of poles through joint use, âDecrease pole density, âIncrease lateral offset, 7 Don L. Ivey, Texas Transportation Institute, College Station, TX 77843. C. Paul Scott, Federal Highway Administra- tion, 400 7th Street, SW, Washington, DC 20590. Current afï¬liation: TBE Group, Inc., 16216 Edgewood Drive, Dumfries, VA 22026.
âIncrease spacing, and âLocate poles where they are less likely to be struck (includes underground). â¢ Use safety devices: âCrash cushions, âSteel reinforced safety poles, âGuardrail, and âConcrete barriers. â¢ Warn motorists of obstacles: âPole delineation (reï¬ective paint, sheeting, markers on poles), âRoadway lighting, âWarning signs, and âRumble strips. KEEP VEHICLES ON THE ROADWAY One obvious way to reduce utility pole crashes is to assist the driver in staying on the roadway. This may be done by positive guidanceâfor example, by using pavement markings, roadside delineators, advance warning signs, and other visual cues to tell the driver what to expect and to provide a good visual path through a site. Physical enhance- ments such as improving the skid resistance of the pavement, improving drainage, widening the pavement travel lanes, widening or paving shoulders, improving the superelevation, straightening sharp curves, decreasing the speed of vehicles, and adding lighting in areas where crashes frequently occur at night may also diminish crash poten- tial by decreasing the number of vehicles leaving the travelway. Trafï¬c calming tech- niques also may be appropriate in some areas. Improving the probability of vehicles staying on the roadway should not be neglected but can never be 100% effective. The preceding countermeasures should be considered along with decisions about the necessity of removing, relocating, or shielding utility poles. Where there are also trees, buildings, or other obstacles for errant vehicles to hit, run-off-the-road crashes caused by roadway problems may not be reduced signiï¬cantly merely by removing or relocating utility poles. Keeping vehicles on the roadway is, therefore, a critical consideration when evaluating solutions to collisions with roadside obstacles. Improvements to help keep vehicles on the roadway are clearly a state DOT or local HA function. CHANGE POLE POSITION OR REMOVE The most direct solution is to remove the utility pole or poles, but often this is not prac- tical. Another solution for consideration is to relocate poles farther away from the road, preferably in a location where they are less likely to be struck (e.g., behind a ditch or exist- ing guardrail or on the inside of a curve). Countermeasures that reduce the number of poles may include combining utilities from separate poles (joint use) or increasing the spacing between poles. Before adopting any of these procedures, an engineering study is needed to determine whether the changes would be cost-effective and appropriate for the speciï¬c site. For example, increasing the spacing of poles requires that the remaining poles be larger and taller than the previous ones, and this is not a simple solution. In many cases, pole spacing is dictated by conductor size and characteristics and by codes and conductor spacing/clearance requirements. In all cases, pole spacing is a combination of various restrictive factors such as agency restrictions, pole loading, and customer service requirements. Ideal span lengths for power poles may be too great for communication conductors. Typically, joint use spans are shorter than power line spans. 8 Utilities and Roadside Safety
Removing or relocating one or a few poles in areas of high hazard is often considered as a treatment when several crashes have occurred. This countermeasure may be partic- ularly appropriate in rural areas where pole spacing is not as dependent on customer service. Removing or relocating utility poles is clearly a utility responsibility. Burying utility distribution lines and removing existing poles would clearly eliminate future pole crashes, but cost is a critical consideration. Installation costs, repair costs if damaged, and routine maintenance costs will be higher. Also, undergrounding may not eliminate the potential for crashes with other roadside objects, such as trees, walls, build- ings, and so forth. In some cases, collisions with the remaining obstructions may result in as severe an accident as collisions with the original pole line. When looking at the fea- sibility of undergrounding utilities, the complete roadside area and nearby adjacent properties should be evaluated for potential roadside obstructions or hazards. Above- ground appurtenances associated with underground utility facilities (transformers, switching cabinets, terminals, etc.) are larger than utility poles and in most cases are too large to be installed on the right-of-way (Figure 1). They may require private easements from adjacent property owners. If they are struck by a vehicle, the results may be as severe as striking a pole. In considering undergrounding it also should be kept in mind that additional pad- mounted transformers would be required to serve the same customers because of the limitations on secondary electrical service conï¬gurations and limiting of current carry- ing capacity on the underground cables due to heat dissipation. Placing transmission lines underground reduces the amount of current carrying capacity and restricts the loca- tion of other utility facilities. If they are placed in conduits, the capacity of buried cable is reduced about 50%. Speciï¬c issues for consideration when evaluating the practicality of undergrounding are as follows: â¢ Installation of aboveground facilities (transformers, switching cabinets, terminals), â¢ Easement requirements for facilities too large to be installed in the right-of-way, Solutions 9 FIGURE 1 Examples of aboveground electrical equipment and mini-substation: (a) pad-mounted switch cabinet; (b) phase pad-mounted transformer; (c) pad- mounted transformer; (d ) mini-substation. (a) (b) (c) (d)
â¢ Presence of other existing underground facilities, â¢ Facility and customer service conversion costs (usually high and borne by the request- ing agency), and â¢ Space requirements (right-of-way space needed for underground facilities is more than double that required for overhead installations). In spite of the difï¬culties, an underground installation may be an effective design solu- tion. In many cases, it can be justiï¬ed only in new design based on aesthetic considera- tions. Rarely will it prove to be a cost-effective solution to existing facilities. SAFETY DEVICES It is clear that all safety devices do not ï¬t every location. Often only one is applicable to a particular site. An on-site inspection, preferably attended by state DOTs, local HAs, and utility personnel, is usually required to ensure an effective choice. Appendices A and B provide practical examples for making those choices. While many safety options are not new to the highway/utility community, some have been designed and tested speciï¬cally for use in reducing utility maintenance and guard- ing the public from impacts with utility poles. Others are clearly applicable to pole sites. A few of these are discussed in the following subsections. Low-Proï¬le Barrier The low-proï¬le barrier (LPB) is simply a short portable concrete barrier (20 in. tall). In total lengths of about 40 ft, it can be placed to prevent vehicle entry into an area where a pole is within the needed clear zone. The length of each concrete segment is 20 ft. The cost is about $25.00 per foot. It is qualiï¬ed under NCHRP Report 350 (3) Level 2 (45 mph) and is used extensively in construction zones in Texas. Currently, there are nine con- tractors or precasters licensed to produce LPBs in Texas. Over 100,000 ft have been cast and used on Texas highway projects (Figure 2). 10 Utilities and Roadside Safety FIGURE 2 LPB, construction zone.
Guardrail Extruder Terminal ET-2000 and similar guardrail extruder terminals (Figure 3) have been broadly applied in the United States in the past 6 years. To date, over 50,000 extruders have been installed in 42 states. Crash Cushions Crash cushions ranging from simple effective sand-filled barrels to the most sophis- ticated NCHRP Report 350 (3) Level 3 devices are available. At least four different designs [sand-filled barrels, EASI-cell cluster system (Figure 4); TRACC; REACT; and QuadGuard] are approved by FHWA for use on the National Highway System. Of the Solutions 11 FIGURE 3 Extruder terminal and guardrail (guardrail installation on pole).
three solutions that usually render any needed changes in pole structure or placement unnecessary, QuadGuard occupies the least space but is the most costly. Where space is available, sand-filled barrels are a more cost-effective solution. Figure 5 shows a recent installation in Lafayette, Louisiana. The cost of barrels was less than $2,500. Note how chevrons have been used to better delineate the curve. Breakaway Guy Wires Several breakaway guy wire systems have been or are in the process of being developed. They are discussed in the following paragraphs. The UTD Safety Link1 is a breakaway mechanism for utility pole guy wires. It has been crash tested and meets the requirements of NCHRP Report 350 (3). It consists of a threaded steel rod inside a two-piece cylinder. When an errant vehicle strikes the link, the two-piece outer cylinder bends at the joint. This increases the tension in the threaded rod until it fails, releasing the guy wire connection to the ground. This device has been approved by FHWA for use on the National Highway System. Another breakaway guy wire has been developed2 under an FHWA Small Business Enterprise Research contract. It has been successfully crash tested with a pendulum. It had previously been successfully crash tested at high speed with a small car. The test report and ï¬nal report are currently not available, and it has not been approved by FHWA for use on federal-aid highways. The starting point for these newer breakaway guy wire designs was provided by an operational breakaway guy wire connection developed and successfully tested in 1986 under an FHWA-sponsored research project. A 6-ft-long frangible transition piece, made of 3â4-in. galvanized pipe, was added between the guy cable and the anchor. Details of the design are presented in FHWA Report FHWA/RD-86/154, Safer Timber Utility Poles (4). WARN MOTORISTS OF OBSTACLES The number of crashes and the severity of crashes may sometimes be decreased by warn- ing motorists of the presence of poles adjacent to the roadway. This may be done with warning signs, reï¬ective paint, sheeting, object markers placed on utility poles, or road- 12 Utilities and Roadside Safety FIGURE 4 EASI-cell cluster system. 1UTD, Inc., of Manassas, Virginia. 2Foster-Miller, Inc.
Solutions 13 FIGURE 5 Use of crash cushion in Lafayette, Louisiana. (a) (b) way lighting. It is considered a last resort in some cases where more comprehensive treat- ments are not practical. State DOTs, local HAs, and utilities can work together to warn motorists of obstacles. EMERGING SOLUTIONS In addition to the preceding safety devices, several new devices are now or soon will be available to reduce the number and severity of utility pole crashes. An example is the energy-absorbing ï¬berglass-reinforced composite utility pole.3 This composite pole meets structural performance requirements for environmental loading in accordance with the National Electrical Safety Code for Class 4 poles and safety performance criteria in com- pliance with NCHRP Report 350 (3) Test Level 2 conditions for utility poles. Crash tests have demonstrated the ability of the composite pole to absorb vehicle impact energy by progressive crushing and fracture propagation as the vehicle is brought to a controlled stop. This design meets a critical need in an area where there is no run out room available and no room for barriers or crash cushions. INTELLIGENT TRANSPORTATION SYSTEM APPLICATIONS Engineers and researchers4 are working together on methods to increase driver awareness of known, dangerous roadway conditions and roadside obstacles, including utility poles. Awareness of hazardously located utility poles has been proposed by integrating infra- structure technologies with in-vehicle technologies. This might include the following: 3Developed by Shakespeare Composites and Electronics, DE Technologies, Inc., and Dynatech Engineering, Inc. 4Foster-Miller, Inc., and Battelle Memorial Institute.
â¢ Enhancing night vision by equipping vehicles with ultraviolet headlamps or infrared night vision sensors and by painting utility poles with ï¬uorescent or high-emissivity paint. â¢ Providing navigational or route guidance by equipping vehicles with a Global Position- ing System and embedding hazardous pole locations on digital maps. â¢ Providing early warning by equipping vehicles with radar sensors or transponders and positioning transmitters near potentially hazardous poles. While these suggested countermeasures may seem impractical at this time, so did providing electricity for farmers in the 1930s. COST COMPARISONS As mentioned previously, keeping vehicles on the roadway should be a critical consid- eration when evaluating solutions to collisions with utility poles. Even so, there will be times when state DOT, local HA, and utility engineers agree there are no feasible or cost- effective ways to do this and other countermeasures must be considered. In this section, comparison of the overall cost of several of these different courses of action is attempted, while fully understanding many of these costs are highly variable. The first and admittedly rare situation is that there is a certain pole in a certain high- way right-of-way that is subject to a severe hit each year. This is presented in Table 1. A severe hit is one in which serious injury or death of one driver or passenger is expected. Estimated costs are compared over a 5-year period. For these example pur- poses, the action/inaction year is 2002 and costs are estimated through 2006. There is no consideration of inflation or the cost of money so in economic terms the comparison is simplified. Table 1 presents estimates of cost for five âactionsâ and for âno action.â They are as follows: â¢ No action, â¢ Relocation of pole, â¢ Installation of a steel-reinforced safety pole (AD-IV, FHWA, or Hawkins), â¢ Installation of concrete barrier (LPB), â¢ Installation of guardrail with extruder terminal, and â¢ Installation of a short crash cushion (Level 2). Table 1 is divided into initial, maintenance, loss of service, and potential liability costs. In the last column, the total 5-year cost (neglecting liability) is presented. Figure 6 pre- sents a graphic comparison of the different action costs over the 5-year period. The most costly, even neglecting potential liability costs, is clearly doing nothing. Although relo- cation of the pole may be the most costly in the short term, over a 5-year period it com- pares favorably with other alternatives. If the comparison extends beyond 5 years, relocation clearly becomes more and more cost-effective. If 5-year costs vary between $3,000 and $15,000 for the various rail, cushion, and break- away devices compared, why is this variety needed? In a situation in which removal is not feasible, only one of the other three alternatives may be appropriateâfor example, if there were as much as 15 ft available, a crash cushion might ï¬t. For a more detailed dis- cussion of where each device would or would not be feasible, see Ivey and Mak (5). Three other hypothetical situations are considered. They are as follows: â¢ Table 2 and Figure 7: One severe collision with a pole in a 5-year period; â¢ Table 3 and Figure 8: Five severe collisions with any of three poles in a 300-ft length of pole line in a 5-year period (taken from PennDOT) (6); and â¢ Table 4 and Figure 9: Eight severe collisions within a 3,000-ft length containing 20 poles in a 5-year period (taken from PennDOT). 14 Utilities and Roadside Safety
Solutions 15 Action Initial Cost Maintenance Cost per yr 5yrs Loss of Service /yr $5yrs Potential Liability Total 5-Year Cost* None 0 $2,000 $10,000 $4,000 $20,000** $ 5m $30,000 Relocate Pole $3,000 to $15,000 $9,000 avg. 0 0 0 0 0 $ 9,000 AD-IV Breakaway $2,000 $1,000 $5,000 0 0 0 $ 7,000 LPB Concrete $1,000 $ 200 $1,000 0 0 0 $ 2,000 Extruder Guardrail $2,000 $1,000 $5,000 0 0 0 $ 7,000 Crash Cushion $5,000 $2,000 $10,000 0 0 0 $ 15,000 * No potential liability cost included. ** Assumed $1,100/service hour lost. TABLE 1 Summary of Costs for 5 Years: Pole Struck Once per Year *I f c ra sh c us hi on c os t i s $5 00 0 A cc um ul at ed C os t N o Ac tio n Cras h Cu shion * Gua rdra il Relocate Pole SRSP Concrete Year 1 2002 2 2003 3 2004 4 2005 5 2006 $35,000 $30,000 $25,000 $20,000 $15,000 $10,000 $5,000 FIGURE 6 Summary of costs for 5 years (pole struck once per year, one pole affected). Action Initial Cost Maintenance Cost per Collision Loss of Service Potential Liability Total 5-Year Cost* None 0 $4,000 $3,000** $200,000 $7,000 Relocate Pole $3,000 to $15,000 $9,000 avg. 0 0 0 $9,000 AD-IV Breakaway $3,000 $1,000 0 0 $4,000 LPB Concrete $2,000 $ 200 0 0 $2,200 Extruder Guardrail $3,000 $2,000 0 0 $5,000 Crash Cushion $5,000 $2,000 0 0 $7,000 * No potential liability cost included. ** Estimated $1,100/service hour lost. TABLE 2 Summary of Costs for 5 Years: Pole Struck Once per 5 Years, One Pole Affected *I f c ra sh c us hi on c os t i s $5 00 0 A cc um ul at ed C os t No Action Relocate Pole Year 1 2002 2 2003 3 2004 4 2005 5 2006 $10,000 $7,500 $5,000 $2,500 Crash Cushion* Guardrail SRSP Concrete FIGURE 7 Summary of costs for 5 years (pole struck once per 5 years, one pole affected).
16 Utilities and Roadside Safety Action Initial Cost Maintenance Cost per Hit 5 Hits Loss of Service /yr $5 yrs Potential Liability Total 5-Year Cost* None 0 $4,000 $20,000 $3,000 $15,000** $ 1m $35,000 Relocate Pole $3,000 to $15,000 $9,000 (avg.) x 3 = $27,000 0 0 0 0 0 $27,000 AD-IV Breakaway $1,000 $5,000 0 0 0 $14,000 LPB Concrete $2,000 x 3 = $6,000 $ 200 $1,000 0 0 0 $ 7,000 Extruder Guardrail $3,000 x 3 = $9,000 $3,000 x 3 = $9,000 $2,000 $10,000 0 0 0 0 $19,000 Crash Cushion $5,000 x 3 = $15,000 $2,000 $10,000 0 0 $25,000 * No potential liability cost included. ** Estimated $1,100/service hour lost. *I f c ra sh c us hi on c os t i s $5 00 0 A cc um ul at ed C os t N o Ac tio n Cras h Cu shion * Gua rdra il Relocate Pole SRSP Concrete Year 1 2002 2 2003 3 2004 4 2005 5 2006 $35,000 $30,000 $25,000 $20,000 $15,000 $10,000 $5,000 FIGURE 8 Summary of costs for 5 years (ï¬ve pole hits in 300 ft of pole line, three poles affected). TABLE 3 Summary of Costs for 5 Years: Five Pole Hits in 300 ft of Pole Line, Three Poles Affected In the case indicated in Table 2 (one collision with a pole every 5 years), relocation is more costly (neglecting potential liability) than doing nothing (see Table 2 and Figure 7). In the situation presented in Table 3, ï¬ve collisions in 300 ft, all actions cost less than doing nothing. In the case indicated in Table 4, eight collisions in 3,000 ft, almost all actions with the exception of LPB are more expensive than doing nothing. Note carefully, however, this neglects the potential liability cost of eight severe pole impacts, an estimated $1 million to $6 million.
REFERENCES 1. Roadside Design Guide. AASHTO, Washington, D.C., Jan. 1996. 2. Horne, D. A. Precedents for Action. In Transportation Research Circular E-C030: Utility Safety: Mobilized for Action and State, City, and Utility Initiatives in Roadside Safety. Presentations from TRB Committee on Utilities (A2A07) from the 79th Annual Meeting of the Transportation Research Board, Washington, D.C., April 2001, pp. 7â10. gulliver.trb.org/publications/circulars/ec030/ ec030.pdf. 3. Ross, H. E., Jr., D. L. Sicking, R. A. Zimmer, and J. D. Michie. NCHRP Report 350: Recommended Procedures for the Safety Performance Evaluation of Highway Features. TRB, National Research Coun- cil, Washington, D.C., 1993. 4. Safer Timber Utility Poles. FHWA Report FHWA/RD-86/154, FHWA, 1986. 5. Ivey, D. L., and K. K. Mak. Recommended Guidelines for New Utility Installations. Presented at the Symposium on Safety in the Clear Zone and Utility Installations. Committee on Utilities, Transportation Research Board, National Research Council, Washington, D.C., June 25, 1989. 6. Comprehensive Utility Pole Safety Plan. Department of Transportation, Commonwealth of Penn- sylvania, Harrisburg, Jan. 10, 1990. Action Initial Cost Maintenance Cost per Hit 8 Hits Loss of Service /yr $5 yrs Potential Liability Total 5-Year Cost* None 0 $4,000 $32,000 $3,000 $24,000** $ 6m $56,000 Relocate Pole $3,000 to $15,000 $9,000 (avg.) x 20 = $180,000 0 0 0 $180,000 AD-IV Breakaway $3,000 x 20 = $60,000 $1,000 $8,000 0 0 $68,000 LPB Concrete $2,000 x 20 = $40,000 $ 200 $2,000 0 0 $42,000 Extruder Guardrail $3,000 x 20 = $60,000 $2,000 $40,000 0 0 $100,000 Crash Cushion $5,000 x 20 = $100,000 $2,000 $16,000 0 0 $116,000 * No potential liability cost included. ** Estimated $1,100/service hour lost. TABLE 4 Summary of Costs for 5 Years: Eight Pole Hits in 3,000 ft of Pole Line, 20 Poles Affected *I f c ra sh c us hi on c os t i s $5 00 0 or le ss A cc um ul at ed C os t No Acti on Guardrail Relocate Pole SRSP Concrete Year 1 2002 2 2003 3 2004 4 2005 5 2006 $200,000 $100,000 Crash Cushion* FIGURE 9 Summary of costs for 5 years (eight pole hits in 3,000 ft of pole line, 20 poles affected). Solutions 17