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E-1 A P P E N D I X E Utility Pole and Tree Safety Case Studies Taken Directly from: Noteworthy Practices: Roadside Tree and Utility Pole Management, Federal Highway Administration, by Joseph Jones, Leidos, September 2016. A 2016 report by Joseph Jones for FHWA entitled Noteworthy Practices: Roadside Tree and Utility Pole Managementâ provided some case studies of what some state DOTâs have been doing to address roadside safety problems in recent years. The report first discusses that roadway departures accounts for a majority (56%) of fatal crashes in the U.S., and of those crashes, 40% involve striking a fixed object. Vehicles which strike trees or utility poles are said to represent 14% of all fatal crashes. The study suggests thatâ¦âmanaging roadside trees and utility poles would be common strategies to reduce fatal crashes; however, most transportation agencies have indicated that they find it challenging to mitigate these obstacles. A few state departments of transportation (DOT) apply some level of roadside management in the area and their practices are examined here in greater detail.â The study states that mitigating crashes involving these two types of roadside objects: âare arguably the most elusive of all fixed objects to control for the following reasons: â¢ Trees contribute to roadside aesthetics and their removal sometimes invokes deep sentimental and environmental concerns among agencies and stakeholders (NCHRP 500, Volume 3 on Trees) â¢ Utilities are usually privately held business enterprises that are not bound by State DOT policies. If they have rights regarding poles in public rights-of-way, they are allowed to ignore or reject requests for removal.â Reduced budgets for maintenance and operations are mentioned in the report, and reduced personnel are given as further reasons why more is not being done by state DOTs to address these problems. Also, the authors state that there is lower priority assigned to dealing with these safety issues. The study mentions that it attempts to present aâ¦ âsnapshot of multiple methods gleaned from a cross-section of industry.â
E-2 Utility Pole Safety and Hazard Evaluation Approaches 1. Remove the obstacle (if possible). 2. Redesign the obstacle (so it can be traversed by the errant vehicle). 3. Relocate the obstacle so a collision is less likely. 4. Reduce crash severity, such as by using a breakaway feature. 5. Shield the obstacle using a longitudinal barrier or crash cushion. 6. Delineate the obstacle if the measures above are not feasible. Since trees and utility poles are not traversable (see objective 2), the study focus is on measures that address the objectives of keeping the vehicle on the road, allowing the errant vehicle to recover after leaving the travel lane, and reducing the crash severity. Some of the specific âcase studiesâ described from selected states are given below. The case studies taken from that report involve programs that deal with utility pole crash countermeasures, but some involve broader roadside safety approaches of efforts to reduce roadside crashes in general: KEEP THE VEHICLE ON THE ROADWAY ALABAMA DOT: Alabama: Applying Specific Countermeasures Corresponding to Individual Crash Types (1). Alabamaâs roadside tree and utility pole management program is a direct product of FHWAâs Roadway Departure Focus States Initiative. This program identifies a Stateâs most critical crash types and identifies countermeasures that can be deployed to decrease fatalities and serious injuries. In response to FHWAâs analysis, the Alabama Department of Transportation (ALDOT) developed a program and funding stream to address over 400 areas in which roadside fixed object crashes were overrepresented. ALDOT established an open-ended program to focus on both curve and tree/pole problem areas. They retained two design consultants to more closely analyze each problem area and tailor a specific solution to alleviate the concern. This practical approach uses the data and context for each particular area to devise a solution rather than deploying a single treatment (e.g., clearing) statewide. While removal of trees is not ruled outâ particularly those very close to the traveled wayâthe solutions are expected to focus on keeping drivers on the roadway, effectively preventing the trees and utility poles from being reached. This could be accomplished by installing HFST, enhanced signing or edge line rumble strips. Widening and/or paving shoulders may also be considered. The ALDOT program has the potential to realize all the benefits of a narrowly focused safety solution while still achieving the widespread advantage of a systemic deployment. Since tree removal is not expected to be the primary solution identified, ALDOT anticipates very little public opposition. If any promotional marketing does need to take place, however, the DOT The study cites the hierarchy given in the AASHTO Roadside Design Guide for addressing hazards within the highway right-of-way:
Utility Pole and Tree Safety Case Studies E-3 described above is ongoing, ALDOT intends to accomplish most of its efforts within 5 years, as funding allows. (1 Telephone Interview conducted with T. Barnett of the Alabama Department of Transportation, Office of Safety Operations, September 25, 2015). WASHINGTON STATE DOT: Washington: Targeting Locations through Network Analysis (2) Over half of the total land area of Washington State is forested. This vast natural resource has allowed the State to become the Nationâs second largest timber producer, supporting over 100,000 jobs in that industry (3). It also means that the Washington State Department of Transportation (WSDOT) owns hundreds of miles of tree-lined roads. For that reason, the DOT has had an active policy of careful roadside tree management for decades. Currently, a sophisticated strategy is in place as part of the Stateâs Strategic Highway Safety Plan (SHSP), but long before that, trees were dealt with as actual crashes revealed the need. Eventually, the Stateâs paving program began to drive tree management efforts; roadside trees were considered for removal when they fell within the limits of a programmed resurfacing, restoration, and rehabilitation (3R) project. Though this was a step in the right direction, by the early 1990s the State realized an additional opportunity to manage hazards more efficiently and moved toward the program that is in place today. WSDOT conducts a biannual comprehensive network analysis that identifies broader areas of potential safety enhancements, not only tree and utility pole issues. The current plan employs a systemic- targeted approach in which countermeasures are coupled with specific crash types, and deployed globally as needed. Since this approach focuses on system performance, crash types, and contributing factors, WSDOT is able to tailor appropriate solutions to individual locations. In the case of trees and utility poles, the countermeasures deployed are generally designed to keep vehicles on the roadway: rumble strips, enhanced pavement marking, edge delineation, and HFST. As such, trees are seldom removed, and although WSDOT has a contract mechanism by which timber can be harvested on right-of-way, it is rarely used. Occasionally, the agency shields the obstacles. When shielding is needed, the State takes a two-pronged approach: â¢ Older installations (50s, 60s and 70s) that may already be shielding obstacles are inspected to verify their performance. The agency upgrades these installations as necessary. â¢ Shielding is installedâas warrantedâif none is currently in place. In some locations, the only significant work in recent history may have been 3R, the scope of which generally excludes additional guardrail. (2 Telephone Interview conducted with J. Ring, A. Nizam, and J. Milton of the Washington State Department of Transportation, September 23, 2015.) (3 Washington Forest Protection Association, âSustainable Forestry.â Available at: http://www.wfpa.org/sustainable-forestry/) plans to highlight the expected annual reduction of 40-50 fatal crashes. While the activity
E-4 Utility Pole Safety and Hazard Evaluation Approaches WSDOT has experienced surprisingly little public opposition to their roadside tree and utility pole management strategy. This may be due to their performance-focused approach: working together with the public to achieve solutions instead of simply informing them of the plan. While satisfying the concerns of all transportation stakeholders rarely occurs, the agency has had success with achieving public consent with their analytical, data-driven approach. PENNSYLVANIA: INCREASING SAFETY IN CULTURALLY SENSITIVE AREAS The legislature in the State of Pennsylvania has, for over a decade, appropriated $10 million annually to fund the transportation-related âLow-Cost Safety Improvement Program.â The programâs funding is distributed among the Pennsylvania Department of Transportationâs (PennDOT) 11 districts. Each district further allocates the money to State routes within their portion of Pennsylvaniaâs 67 counties, which allows funding to be closely tied to the individual needs of each county in the State (4). The scopes of projects within these counties vary greatly. Low-cost, systemic type projects such as HFST and rumble strip installations are most frequently undertaken, but more complex projects such as road widening or limited new construction are occasionally built. While this program is not limited to tree and pole mitigation efforts, that work is often accomplished as well. While roadside tree removals are often part of the Stateâs efforts, one notable case caused officials to consider other countermeasures. Pennsylvania Route 147 in Dauphin County is nicknamed âSycamore AllÃ©e,â for the nearly century-old mature sycamores that line its sides. Listed on the National Register of Historic Places, the tree plantings along this roadway segment north and south of Halifax have uncertain origins, though they are largely believed to have been a memorial to World War I soldiers from the county who were killed in action (5). When the mature trees along Route 147 were identified as an opportunity for safety improvement, PennDOT officials immediately knew that tree removal was not an option. Instead of introducing the increased crashes inherent in excessive shielding, the DOT decided to focus on keeping vehicles on the roadway. The Department accomplished this by designing HFSTs and superelevation corrections. The initial projects containing these countermeasures are presently under construction, so no performance data is available. Like many other transportation agencies, however, PennDOT has realized a pronounced decrease in roadway departure crashesâat other locationsâresulting from HFST. 4 Telephone Interview conducted with J. Herschock of the Pennsylvania Department of Transportation Office of Safety Engineering and Risk Management, September 23, 2015. 5 Pennsylvania Historic Preservation Office, âNational Transportation Week: A Road to the Past,â last modified: May 15, 2013. Available at: http://pahistoricpreservation.com/a-road-to- the-past/.
Utility Pole and Tree Safety Case Studies E-5 TENNESSEE: MANAGING ROADSIDES WITH ENVIRONMENTAL CONSTRAINTS The Tennessee Department of Transportation (TDOT) generally avoids removing either trees or utility poles from their rights-of-way or from adjoining properties primarily due to two factors: environmental concerns or public resistance. In Tennessee, removing trees or shrubs larger than 6 inches in diameter triggers additional environmental studies and impact statements. This is complicated by the stateâs being home to at least three species of endangered bats and having an environmental requirement that root wads of cut trees be left in the ground for soil stabilization. In many cases, a new tree can re-grow from the root stock. Additionally, landowners in the state are very resistant to having trees on or along their property removed, regardless of risk to motorists. Being cognizant of the risks that roadside trees and utility poles present, TDOT searched for a solution that could be deployed quickly and without generating undue environmental or public relations concerns. The answer was tree and pole delineation. The delineation consists of either a curved retro-reflectorized plate affixed to the tree or pole, or a standard ground-mounted flexible delineator installed near the obstacle. TNDOT began using this countermeasure with regularity in 2012. Given the low level of complication and intrusion associated with this product, the agency has not encountered any opposition on the part of transportation stakeholders or utility companies. TNDOT will only delineate utility poles that are within the clear zone, and furthermore, only those on the foreslope. This is specifically done to avoid drivers mistaking the delineation for channelization. Even with this policy in place, they field check each potential application site (in person) to determine the possibility of drivers being drawn off the road. If the team believes that possibility exists, the treatment is not used. A few agencies nationwide have used this countermeasure but no research at this time provides definitive results. As such, no rating is included in the CMF Clearinghouse. ALLOWING THE VEHICLE TO REGAIN THE ROADWAY NEBRASKA: RE-ESTABLISHING CLEAR ZONES DURING RESURFACING, RESTORATION, AND REHABILITATION (3R) AS WELL AS RESURFACING, RESTORATION, REHABILITATION AND RECONSTRUCTION (4R) Nebraska Department of Roads (NDOR) policy stipulates that fixed objects within the right-of- way are to be removed for any project classified as 3R and higher using the minimum clearance widths shown below. The distance cleared is variable based upon roadway functional classification and average daily traffic (ADT).
E-6 Utility Pole Safety and Hazard Evaluation Approaches TABLE E1: NDOR FIXED OBJECT CLEARANCE WIDTHS Functional Classification Average Daily Traffic Lateral Obstacle Clearance (ft) Interstate All Expressway All Major Arterial Minor Arterial 2,000 - 3,999 Major Arterial 400 - 1,999 Minor Arterial < 400 This practice has been in place since the 1980s, but has become especially important in recent years when Nebraska, like so many other States, changed its mowing policy. The department used to mow the entire right-of-wayâfrom fence line to fence lineâbut now only mows a single pass adjacent to the roadway. This allows more substantial vegetation like trees and shrubs to take root and flourish. When adhering to NDORâs policy, obstacles of this nature are removed or otherwise controlled on the normal paving schedule: about every 10 years. Since this policy is codified into State law, it is able to transcend any public opposition that may arise and, to date, the public has not voiced any opposition to NDOR concerning this practice. It is important to remember that NDORâs policy goes beyond trees alone and applies to all fixed objects. Utility pole concerns within the above-specified clear recovery areas are handled on a case-by-case basis. A Roadside Safety Analysis Program assessment is usually completed and if a concern is detected, the department works with the utility company for relocation, or shields the pole. REDUCE THE SEVERITY OF CRASHES NEW JERSEY: USING POLES THAT ABSORB CRASH ENERGY Utility pole crash fatalities are disproportionate in New Jersey, a State that ranks 22nd in all traffic fatalities, but 8th in those involving utility poles (6). Approximately 260 sites have been identified statewide as having multiple utility pole crashes over a 3-year period. 4,000 35 30 30 30 23 16
Utility Pole and Tree Safety Case Studies E-7 With this in mind, New Jersey Department of Transportation (NJDOT), in conjunction with researchers at Rowan University, developed the Pole Mitigation Program to identify and improve highest-risk utility pole crash locations. Twenty sites that are not part of any active design or construction effort have been selected for mitigation (7). Within the PMP there is an effort to pilot the use of energy-absorbing poles at some locations. These poles differ in many ways from their wood and steel breakaway counterparts. The hollow poles feature composite construction consisting of filament-wound fiberglass-reinforced polyester. They are 45 feet long with a wide octagonal cross-section on the lower portion that transitions to a narrow circular cross-section near the top (8). The poles are designed to collapse upon impact as opposed to breaking away and potentially falling into traffic. Analysts observed no excessive occupant risks factors in either of two separate crash tests (9). 6 H. C. Gabler, D. Gabauer, and W. Riddell, Breakaway Utility Poles: Feasibility of Energy Absorbing Pole Installations in New Jersey, (Trenton, NJ: New Jersey Department of Transportation, 2007), p.8. the 82nd Annual TRB Meeting, Washington DC, January 2003). As shown below, these poles offer several advantages over traditional wooden poles. TABLE E2: COMPARISON OF COMPOSITE POLE TO WOODEN POLE. Characteristic Composite Pole Wooden Pole Weight 475 lbs. 1,000 lbs. Service Life 80 yr. (consistent performance) 20-50 yr. (declining performance) Maintenance None 5-7 years While NJDOT initially experienced hesitation from the utility companies when they were invited to participate in the PMP, continued outreach eventually produced an agreement for replacing and installing fiberglass poles when possible in accordance with the policy. REPORT CONCLUSIONS Among other things, the FHWA report recommends placing utility poles and trees which are 4 inches in diameter or greater at a distance of at least 6 feet from the curb in urban areas. The report also refers to the AASHTO Roadside Design Guide for further guidance. 7 Foedinger, R., et al, âDevelopment of an Energy Absorbing Pole,â (paper presented at 8 Ibid., p. 28. 9 Ibid., p. 29.