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1 Background Crashes and related deaths and injuries involving utility poles have been a problem in the United States for many decades. Recently, more than 900 people died annually, and approxi- mately 40,000 more were injured each year in collisions with utility and light poles along streets and highways. Utility poles are second only to trees as the most commonly struck fixed object in fatal crashes on the nationâs highways in recent years (NHTSA 2018). Historical estimates document more than 100 million rigid utility poles within U.S. highway rights-of-way, with an estimated 75,000 utility pole collisions each year. These numbers correspond to nearly 4 million utility pole collisions over the past 50 yearsâand currently about nine collisions per hour, or one vehicle striking a utility pole every 7 minutes (Ivey and Scott 2017). In terms of fatalities, over the 50 years between 1965 and 2015, approximately 63,000 people died as a result of utility pole collisions in the United States (NHTSA 2018). Highway engineers have recognized the unforgiving nature of utility poles and other rigid fixed objects since the 1960s. In the intervening years, the design of roadsides has changed dramatically. Breakaway ground-mounted signs and luminaire supports, crash cushions, traversable clear zones, crashworthy guardrails and bridge rails, and safer drainage structures are just some of the changes that have likely saved tens of thousands of lives. Some state trans- portation agencies (STAs) also have made improvements to utility pole-placement policies, and efforts are routinely undertaken to situate new utility poles as close to the right-of-way line as possible, per federal guidelines. Many utility poles in high-risk locations before 1967 have since been removed, relocated to safer locations, or otherwise improved in terms of safety (Ivey and Scott 2004). STAs and local public agencies (LPAs) are major stakeholders in addressing this safety problem. In cooperation with affected utility owners (UOs), they may take the lead in devel- oping safety programs designed to identify poles in high-risk locations, prioritize them for mitigation, and coordinate with UOs to tackle the problem through measures such as pole relocation, pole removal, pole shielding, conversion to less rigid (i.e., breakaway) poles, and/or delineation. UOs can also take the lead in reducing the risks of pole collisions because they are in a position to make positive decisions that will serve the needs of their managers, employees, stockholders, and the public for many years to come. A few STAs, LPAs, and UOs have implemented these basic steps while others are still being encouraged to initiate this process. Table 1 briefly overviews some of the key studies relevant to utility pole safety between 1965 and now. Despite these activities, utility pole fatalities continue at the rate of approximately 900 each year, in addition to the thousands of nonfatal injuries annually from collisions with utility poles. S U M M A R Y Utility Pole Safety and Hazard Evaluation Approaches
2 Utility Pole Safety and Hazard Evaluation Approaches Year Agency Author Title 1967 AASHTO Yellow Book Design and Operational Practices Related to Highway Safety 1973 FHWA Wentworth Motor Vehicle Accidents Involving Utility Polesâ Summary of Data Availability 1974 AASHTO Yellow Book Design and Operational Practices Related to Highway Safety 1980 FHWA Mak and Mason Accident AnalysisâBreakaway and Nonbreakaway Poles, Including Sign and Light Standards Along Highways 1980 NCHRP Michie and Mak Interim Criteria for Identifying Timber Utility Poles for Breakaway Modification 1983 TRB Zegeer and Parker Cost-Effectiveness of Countermeasures for Utility Pole Accidents 1986 FHWA Ivey and Morgan Timber Pole Safety by Design 1987 AA&P Good, Fox, and Joubert An In-Depth Study of Accidents Involving Collisions with Utility Poles 1989 TRB Ivey and Mak Recommended Guidelines for New Utility Installations 1991 NHUC Ivey The Time Has Come for Utility Pole Safety Programs 1992 FHWA Buser and Buser The Breakaway Timber Utility Pole: A Survivable Alternative 1993 NCHRP Ross et al. Recommended Procedures for the Safety Performance Evaluation of Highway Features 1993 TRB Ivey, Branstad, and Griffin Guardrail End Treatments in the 1990s 1995 FHWA Hehr The First Installation of Breakaway Timber Utility Poles 2011b AASHTO AASHTO Roadside Design Guide (RDG) 2001 TRB Scott and Ivey Utility Poles and Roadside SafetyâThe Road to Responsibility 2004 NCHRP Lacy et al. Report 500, Volume 8 2004 TRB Ivey and Scott Utilities and Roadside Safety, TRB State of the Art Report 9 2007 New Jersey Department of Transportation (DOT) Gabler, Gabauer, and Riddell Breakaway Utility Poles: Feasibility of Energy-Absorbing Utility Pole Installations in New Jersey 2009 AASHTO AASHTO Manual for Assessing Safety Hardware (MASH), First Edition FHWA Federal Highway Administration NCHRP National Cooperative Highway Research Program TRB Transportation Research Board AA&P Accident Analysis and Prevention NHUC National Highway Users Conference Table 1. Examples of key studies on utility pole safety since the 1960s.
Summary 3 Purpose of Report The purpose of this synthesis report is to summarize the strategies, policies, and tech- nologies that STAs and UOs use to respond to safety concerns associated with utility poles. Information was gathered from a comprehensive literature review and also from the results of STA and UO surveys and interviews. Specific areas of interest for this synthesis report include methods employed to identify problem poles at high-risk locations, pole-placement policies, strategies and countermeasures applied to reduce the risk of pole-related collisions and resulting injuries and deaths, and funding sources for implementing countermeasures. Case studies were developed for exemplary STAs and UOs, highlighting some of their utility pole safety activities. STA Survey Results Of the 50 STAs surveyed for this study, 92% (46 of 50) responded or were able to participate. Valuable information was shared regarding the current state of safety practices for utility poles. Safety programs, guidelines, and countermeasures in use by STAs to improve utility pole safety were identified. Utility Pole-Placement Guidelines Utility pole-placement guidelines typically follow those established in the AASHTO Green Book, A Policy on Geometric Design of Highways and Streets (AASHTO 2011a), and the AASHTO Roadside Design Guide (AASHTO 2011b), which focus on placing utility poles as close to the right-of-way lineâand as far from the roadwayâas possible. A few states provide additional guidance, such as minimum pole offset distances from the road in urban areas (e.g., 5 feet from the road) and in rural areas (e.g., 10 feet from the road). In some states, the guidance is to avoid placing poles in high-risk areas, such as close to the road on the outside of horizontal curves, at the top of a T-intersection, at a lane drop, or in a median or traffic island. Appendix A includes a list of web-based guidelines for utility pole place- ment in each of the 50 states. Exceptions to Placement Guidelines Some STAs provide written criteria detailing when exceptions to the current guidelines are permitted. For example, exceptions are often approved during the design phase of a new road or when a road is widened or reconstructed. Exceptions to STA pole-placement guidelines are usually granted when pole relocation is impractical or too costly or when it would cause an âextreme hardshipâ to the UO. Other STAs allow exceptions when the right-of-way is inadequate and/or the topography (e.g., a steep slope or a jog in the right-of-way line) does not allow an adequate right-of-way. A few other STAs said that exceptions are simply not granted for any reason. Most of the STAs were not aware of local agencies or UOs that had their own pole-placement guidelines that differed from the STA guidelines. Utility Pole Crashes In terms of reporting on utility pole crashes, all but 7 of the 46 STAs responding to the survey identified a separate code for âutility poleâ crash involvement on the stateâs crash report form. However, reporting thresholds vary from state to state. While all states gen- erally require the submission of crash reports to the state department of motor vehicles (DMV) or a related agency, if an injury or fatality occurs, the criteria for reporting property
4 Utility Pole Safety and Hazard Evaluation Approaches damage only (PDO) crashes vary widely and usually range from approximately $200 to $1,000. Thus, total utility pole crash numbers are not reported consistently from state to state. Of the 887 fatal utility pole (plus luminaire) crashes that reportedly occurred in the United States in 2017, more than half were in the 10 states that have the most utility pole fatal crashes (Florida, Texas, California, Pennsylvania, Tennessee, North Carolina, Illinois, New York, Georgia, and Indiana). Of course, these 10 states are also among the states with the largest populations and the highest total miles driven. Tracking High-Risk Poles In terms of STA procedures for tracking high-crash and high-risk pole locations, only 4 of the 46 state respondents to the survey routinely identify poles or locations that have experienced utility pole crashes to support conducting follow-up inspections. However, a total of 14 states reportedly have a process in place to identify utility poles in high-risk locations (e.g., too close to the road, on the outside of horizontal curves, at intersections or lane drops) for potential treatment, regardless of prior crash experience. Safety Measures The traffic engineering or safety engineering office of an STA typically holds responsibility for the selection and implementation of safety measures to address locations where utility pole crashes occur. The countermeasures most often cited as options for treating utility pole safety problems include guardrails, crash-attenuation barrels, shoulder widening or paving, rumble strips, pole-visibility features, steel-reinforced safety poles (i.e., breakaway poles), underground utility lines, and shared utility agreements. The New Jersey DOT mentioned that it uses fiberglass poles in certain situations because they shatter on impact from a motor vehicle, lowering the chance of a severe injury to vehicle occupants (compared to the risks associated with steel and wooden poles). Funding Options Improvements for utility pole safety can be funded by various federal, state, local, and other financing sources. Most of the STAs confirmed the use of federal funds, with many specifically indicating the receipt of Highway Safety Improvement Program (HSIP) funding (FHWA 2016). About half of the STAs verified state funding as part of their safety improve- ment funding. Such financing sources included Strategic Highway Safety Program (SHSP), matching, state maintenance, spot safety improvement, and state safety funds. Nine STAs noted the use of local funds as a partial match for certain projects. Results from the STA survey are listed in Appendix B. Factors Related to Utility Pole Crashes Researchers have conducted numerous studies since the 1970s on utility pole crash factors and potential countermeasures, as illustrated in Table 1. Characteristics of roadways and poles that are related to greater frequency of utility pole crashes include higher volume of vehicular traffic, or average annual daily traffic (AADT); larger number of poles per mile within the highway right-of-way; closer pole offset (i.e., narrower distance between the pole and the roadway); greater roadway curvature (i.e., sharper horizontal curves, steeper vertical grades, or both); lower pavement skid resistance; and lack of proper curve superelevation (Zegeer and Parker 1983). Research indicates that approximately 5% of utility pole crashes lead to injuries for at least one person, and between 1% and 2% of such crashes result in a fatality. A greater chance of
Summary 5 death or serious injury from a utility pole collision was associated with higher impact speeds and greater pole circumference (Mak and Mason 1980). Crashes involving wooden poles (rather than metal poles) were usually more severe, likely because most metal poles analyzed in the safety research also have slip or frangible bases (Zegeer and Parker 1983). In addi- tion, pole crashes on horizontal curves were more severe than crashes on tangents, and pole crashes on tangents were more severe than those at intersections, probably because of higher driving speeds on tangents (Fox, Good, and Joubert 1979). Utility Poles at High-Risk Locations A utility pole in a high-risk location is defined as one that is placed in a position in the roadway environment where the pole carries an above-average risk of an errant motorist striking it and where serious injury or death is a likely outcome of such a collision. Ivey and Scott (2017) estimated that no more than 1/10 of 1% (0.001) of utility poles, or no more than 100,000 such poles, are installed nationwide. Examples of high-risk pole locations (which increase the chance of a collision) include poles close to intersections, poles on the outside of horizontal curves (and close to the road), poles immediately after (and in line with) a lane drop, poles in the roadway median or traffic islands, and poles adjacent to reverse curves (Ivey and Scott 2004). Utility poles in these types of places may be considered to be in high- risk locations and are typically identified as in need of safety measure (Ivey and Scott 2004). Cost-Effectiveness of Treatments In their research in the 1980s, Zegeer and Parker (1983, 1984) developed a utility pole crash-prediction model based on traffic volume (AADT), pole density, and pole offset from the road. This crash-prediction model led to the further development of estimated crash effects and also crash modification factors (CMFs) for countermeasures such as moving poles further from the road (i.e., pole relocation), reducing the number of poles within a roadway section (i.e., increasing pole spacing), employing poles for multiple uses (i.e., removing a line of poles on one side of the road and doubling the number of lines on the poles on the other side), burying utility lines underground (combined with pole removal), and employing breakaway poles. The safety effect of a given roadway treatment is usually expressed in terms of a CMF. For example, if a roadway countermeasure reduces a certain crash type (e.g., utility pole crashes) by 30%, the accident reduction factor (ARF) (i.e., the crash-reduction factor) is 30%, and the CMF is 0.70 (1 â.30 = 0.70). That is, if 10 crashes per year occurred at a site before the treatment, the expectation would be 7 crashes per year after the solution is implemented (0.7 Ã 10 = 7). Based on the CMF values developed in the FHWA study by Zegeer and Parker (1983), estimated cost of pole-related crashes, and cost of countermeasures, the cost- effectiveness charts and tables in this synthesis report address several scenarios. The factors that are most closely related to utility pole crashes include traffic volume (AADT), pole density (i.e., number of poles per mile), pole offset (distance from poles to the roadway), and type of pole (telephone, electric, one-phase or three-phase, or trans- mission pole). Another factor documented as important is the measure of other roadside features (termed a roadside rating) that affect the number of crashes that still occur if a pole is removed, moved, or altered. Several conclusions were evident about generally cost-effective utility pole-related counter- measures. For example, pole relocation, buried underground utilities, multiple-use poles, and breakaway poles were cost-effectiveâi.e., with a benefit-cost ratio greater than 1.0â for many of the analyzed roadway situations. Cost-effective treatments often result when utility poles are initially close to the roadway and when combined traffic volume is moderate
6 Utility Pole Safety and Hazard Evaluation Approaches to high (e.g., AADT exceeding approximately 10,000 vehicles). Such a benefit-cost ratio (greater than 1.0) is also particularly characteristic of (1) poles that are relocated from 5 feet or less to a distance of at least 20 feet from the road and (2) a shift to underground utility lines in conjunction along a corridor, combined with pole removal for âcloseâ poles on high- volume roads. Multiple-use poles (i.e., those that double-up lines on only one side of the road) were cost-effective for many roadway situations. The reduction of pole density alone (by simply increasing the distance between poles) rarely proved to be cost-effective under any situation because of the high cost of pole relocation and the relatively modest safety benefit from this measure (Zegeer and Parker 1983). It is important to mention that moving poles is generally challenging and expensive. Removing or relocating a single pole from the roadside environment is not always appro- priate or practical; often, an entire row of poles and lines would require repositioning to attain the safety benefits and also to transmit the utility line effectively. Countermeasures involving telephone poles are usually less costly than those for poles carrying electric linesâand therefore more likely to be cost-effective compared to similar treatments for larger electric trans- mission poles and lines. Breakaway devices on poles were considered to be cost-effective for individual poles in high-risk locationsâalthough the CMFs for this treatment are still only estimates and not as well established. Because of the large size of transmission poles and the associated costs of moving them, none of the countermeasures involving moving these poles or lines was documented as cost-effective. In such instances, the use of a guardrail or crash- attenuation devices would generally be less costly and much more likely to be cost-effective compared to trying to move these poles (Zegeer and Parker 1983). To put the previous cost-effectiveness discussion in context, it should be cautioned that the cost of crashes and the price of countermeasures have both increased since the refer- enced Zegeer and Parker (1983) study was conducted. Therefore, to compute more up-to- date benefit-cost ratios for various utility pole treatments, the same previously described CMF values could be used, but with more updated costs for countermeasures and crashes for a given roadway situation. For example, researchers would need to obtain newer solution costs from the utility company that owns and maintains the utility poles that would be affected by a proposed safety improvement. In addition, current crash costs are available from FHWA for use in a benefit-cost analysis. Specifically, economic analysis of a given countermeasure, such as a treatment involving utility poles, requires data on the cost of a traffic crash at various severity levels (PDO, injury, and fatality). Harmon, Bahar, and Gross (2018) provided such updated information. A benefit-cost analysis also incorporates input on the interest rate, effectiveness of the solution (i.e., the CMF), and cost of the treatment. The price associated with a specific countermeasure (e.g., pole relocations) should be obtained from the relevant STA or UO, based on previous costs for similar projects under local conditions. STA and UO Utility Pole Treatment Options In addition to actions entailing changes to poles, as previously discussed, a wide range of other treatment options are available to STAs to reduce the incidence of vehicles leaving the roadway and to lessen the severity of any resulting crash. Such countermeasures include crash cushions (e.g., sand inertia barrels), portable concrete barriers, breakaway structures, composite breakaway (e.g., fiberglass) poles, steel-reinforced safety poles (breakaway poles), low-profile barriers, guardrails and extruder terminals, breakaway guy wires, delineations on the roadway or on the poles, and buried duct networks for utility cables. Of course, other
Summary 7 measures also are available to aid in keeping vehicles on the roadway, such as in-advance curve warning signs or chevrons, edge-line rumble strips, superelevations on horizontal curves, and many other design options. Any of these solutions can be considered to reduce the frequency and severity of utility pole crashes under various conditions (Ivey and Scott 2004). Example of a Logical Approach to Utility Pole Safety Program In TRBâs State of the Art Report 9, Ivey and Scott (2004) describe a three-path plan for reducing utility pole fatalities. This plan, as developed and described by Ivey and Scott (2004), explains the following approach options: â¢ Best Offense. This approach identifies sites that are overrepresented in number of collisions, considers available countermeasures, prioritizes sites for treatment, and imple- ments the improvements. â¢ Best Bet. This approach prioritizes identifying potentially hazardous poles and roadway sections, possibly using statistical prediction algorithms, before a crash history develops and also executing appropriate improvements. â¢ Best Defense. This approach is put into practice by striving to meet recommendations in the AASHTO Roadside Design Guide (2011b) and in TRBâs State of the Art Report 9 (Ivey and Scott 2004). Examples of Utility Pole Safety Initiatives Based on information in the literature and survey responses, several STAs and UOs were selected for development of more detailed case studies. The STAs included Washington State, New Jersey, Georgia, and North Carolina. One anonymous STA was discussed in a case example because its utility pole safety program was scaled back in recent years in response to challenges that the STA faced in dealing with UOs within the state. The synthesis report includes this case example with the thought that other STAs might relate to similar challenges and develop their own tailored approaches to address them. To protect privacy, four unnamed UOs were selected for documentation of their utility pole safety practices and policies. Research Needs Based on gaps in knowledge about utility pole safety, several research needs were identi- fied. The report recommends specific research such as the following to fill those gaps: 1. Conduct a study to update the countermeasure-related costs and current CMFs for utility pole treatments that UOs can implement, such as running utilities underground, relocating poles, employing multiple-use poles, and reducing pole density. 2. Evaluate steel-reinforced safety (breakaway), fiberglass, and other yielding poles. Also evaluate the use of various types of barriers, barrier end treatments, and similar devices and determine their feasibility and effectiveness when used to treat high-risk poles that cannot easily be repositioned or removed. Document how the new MASH criteria have affected the use of various roadside safety devices. 3. Perform a study of the safety problems and potential countermeasures for box-span poles (i.e., poles placed at each corner of an intersection âboxâ that can carry various utilities, signs, and signals), buddy poles (i.e., two poles situated next to each other, potentially causing a more severe crash if struck), and other obstacles in high-risk roadside locations. 4. Study the factors and conditions that led some STAs and UOs to place a higher priority on utility pole safety. Determine the measures that might be effective in convincing other agencies to more aggressively implement utility pole safety strategies and policies.
8 Utility Pole Safety and Hazard Evaluation Approaches Analyze how dedicated funding could be made available to STAs, LPAs, and UOs for instituting safety improvements related to roadside and utility pole safety. 5. Develop model policies for STAs and UOs that go beyond the guidance in the AASHTO Green Book (AASHTO 2011a) and the Roadside Design Guide (AASHTO 2011b) and are suited to the specific safety needs of each jurisdiction. 6. Define and document the range of methods that safety officials can employ to track utility pole crashes within an STA and an LPA. In addition, document methods for the identi- fication of high-risk poles, which should produce recommendations for improvement. Document current case studies in use by the STAs.