This project was established to field test and evaluate the effectiveness of Breakaway Timber Utility Poles, which were designed and developed in the late 1980's under an FHWA-sponsored research project.

Each year, about 1,400 people are killed and 65,000 are injured nationwide because of collisions with some of the 88 million utility poles located within road and street rightsofway. In addition to the human suffering involved, these collisions represent a substantial cost to the utility industry in damaged facilities and disrupted service.

Several countermeasures can reduce the hazards of vehicles hitting utility poles. For example, (1) a utility line can be placed underground, (2) a pole might be relocated farther from the edge of the roadway or in an inaccessible area, (3) the number of poles could be reduced through joint use or by increasing span lengths between poles, (4) poles might be located on only one side of the road, (5) a pole can be shielded from impact by placing it behind an existing guardrail or by placing a crash cushion in front of it, or (6) a pole could be designed to "breakaway" upon impact.

Four States are involved in evaluating Breakaway Timber Utility Poles. Projects have been initiated in Virginia, and Texas. Kentucky has retrofitted 10 utility poles and is currently evaluating their inservice performance. Massachusetts installed 19 new poles, which were monitored through February 29, 1992, and an evaluation report was submitted to the Office of Technology Applications on September 1, 1992. A summary evaluation report was distributed to all FHWA field offices in May 1993.

Background
The Federal Highway Administration (FHWA) sponsored research in the early 1980's to develop an economical breakaway timber utility pole that would increase the safety of passengers in impacting vehicles and satisfy design criteria of the utility industry. The resulting design, called the Hawkins Breakaway System (HBS), was successfully crash tested at the Texas Transportation Institute (TTI) and, by 1986, was deemed ready for selective implementation.

The FHWA provided technology applications funds in 1989 for "experimental" installations of the HBS in Kentucky and Massachusetts.

• The Kentucky Utilities Company retrofitted l0 existing utility poles in Lexington with the breakaway device.
• The Massachusetts Electric Corporation and the New England Telephone Company installed 19 new utility poles near Boston. These poles were prefabricated and contained the breakaway device when delivered to the site. The HBS design was substantially modified for these installations. This modified design is called the FHWA design or the Massachusetts design.

The breakaway timber utility poles in Kentucky and Massachusetts were evaluated for two years with the following results:

• All breakaway timber utility poles were exposed to wind, ice, and snow. No pole failures from these natural forces occurred. An incident in Massachusetts displayed the ability of breakaway poles to resist wind loadings that toppled conventional poles.
• Breakaway utility poles in Massachusetts were hit five times by errant vehicles with no resulting serious injuries or interruption of utility service. In all these accidents, the poles were found by utility personnel to be quicker and easier to repair than standard poles, primarily because the need to transfer service lines was eliminated.

On January 27, 1993, the FHWA upgraded the HBS and FHWA (Massachusetts) designs from "experimental" to "operational." This meant the FHWA was satisfied the breakaway device had performed satisfactorily in full-scale crash tests and had demon- strated satisfactory in-service performance, and deemed it appropriate for the breakaway device to be used routinely on Federal-aid highway projects.

On June 17, 1993, the FHWA approved another breakaway design for use on Federal-aid highway projects. This design is called the AD-IV. It is similar to the HBS and FHWA designs in concept but some of the hardware configurations are different.

The FHWA provided technology applications funds in 1995 for installations of the AD-IV in Texas and the FHWA (Massachusetts) design in Virginia.

• The Texas Utilities Electric Company retrofitted 5 existing utility poles in Arlington with the AD-IV breakaway device. The breakaway timber utility poles in Texas will be evaluated for two years. One accident has been reported to date with no apparent serious injuries or interruption of utility service.
• The Delmarva Power Company retrofitted 5 existing utility poles on Virginia's Eastern Shore with the FHWA (Massachusetts) breakaway device. The breakaway timber utility poles in Virginia will be evaluated for two years.

Approval of the use of the HBS, FHWA (Massachusetts), and AD-IV designs for routine use on Federal-aid highway projects does not mean that breakaway timber utility poles are mandated by the FHWA. Rather, they are considered to be an additional countermeasure available to a State as it considers what actions to take in addressing utility pole safety.

Design Recommendations
The HBS design is set forth in Research Report FHWA/RD-86/154, Safer Timber Utility Poles: Volume I - Summary Report, September 1986. The FHWA (Massachusetts) and AD-IV designs are attached to FHWA approval letters. Detailed drawings may be obtained from the FHWA.

There are three basic components shared by the HBS, FHWA (Massachusetts), and AD-IV designs. They are --

• a shear plane created 102 mm (4-in) or less above the ground by two slip base units bolted together,
• an upper hinge to allow rotation of the pole, and
• overhead guy cables or suspension strands supporting telephone lines to support the pole upon being sheared.

The FHWA (Massachusetts) design differs from the HBS design in the following ways:

• The length of the slipbase lower sleeve is 30 inches. It was increased from 17 inches to account for the pole rot problem (timber utility poles are periodically examined for pole rot which reportedly can occur from ground level to a depth of 30 inches).
• The length of the slipbase upper sleeve is also 30 inches. It was increased from 17 inches to make it possible to standardize manufacture, provide interchangeable parts, and offer a bearing surface for an impacting vehicle.
• The interior diameter of the slipbase sleeves is 13.5 inches. It was increased from 16.5 inches to accommodate predominant pole base diameters which are typically 11.5to 12.5 inches.
• The center of the hinge connector is positioned 14.5 feet above the slipbase cut line to provide clearance for most trucks and to avoid interfering with telephone lines attached 17-18 feet above ground level.
• To strengthen the hinge, threaded rods extend through the pole and replace lag screws to attach the hinge straps.
• The suspension strand supporting telephone lines is used for hinge activation and eliminates the support cable used in the original design.
• The slipbase flange thickness is 5/8 inches. It was changed from the original 3/4 inches to prevent flange warping caused from welding gussets to the flange and sleeve.
• A325 slipbase bolts are used rather than the originally specified A490 to avoid hydrogen embrittlement during the galvanizing process.

The AD-IV design differs from the HBS and FHWA (Massachusetts) designs in the following ways:

• Square base plates with a four-bolt connection at the shear plane are used rather than the circular plates with a six-bolt connection.
• The four rotation straps used at the upper hinge are simplified, eliminating three precisely machined holes used as a yielding mechanism in the other designs.
• A wind bolt on the hinge is used in conjunction with each rotation strap, providing the initial bending resistance necessary.

The breakaway timber utility pole is designed to activate when an automobile hits the pole at speeds ranging from 32-96 kilometers per hour (20-60 miles per hour). Only the hinge's four metal straps, the slip base's keeper plate, and some bolts, nuts, and washers should need to be replaced.

Suppliers
The hardware, poles, epoxy, etc. for the Kentucky and Massachusetts installations were purchased from a contractor who is no longer in business. The hardware for the Texas retrofit installations was fabricated by and purchased from the Syro Steel Company. The hardware for the Virginia retrofit installations was fabricated by and purchased from a local supplier.

Costs
The approximate installation costs per breakaway timber utility pole were as follows:

Kentucky HBS Retrofit Design
$1,260 -- Materials
$1,450 -- Labor and Equipment
$2,710 -- Total Cost Per Pole

Massachusetts FHWA New Pole Design
$2,600 -- Materials
$3,000 -- Labor and Equipment
$5,600 -- Total Cost Per Pole

Texas AD-IV Retrofit Design
$1,250 -- Materials
$   ?    -- Labor and Equipment
$   ?    -- Total Cost Per Pole

Virginia FHWA Retrofit Design
$   ?    -- Materials
$   ?    -- Labor and Equipment
$6,000 -- Total Cost Per Pole

Massachusetts believed the additional cost of new poles was justified in order to eliminate unknown variables associated with older existing poles. Massachusetts was also required to provide insurance on the poles, which, as it turned out, was not needed.

Location Considerations
Location considerations are as follows:

• A breakaway timber utility pole should generally be installed at a location where existing utility poles have been involved in accidents, or where the potential for such accidents is very great.
• A breakaway timber utility pole should not be installed at a location where it is more feasible to remove the existing utility pole, to place the utility line underground, or to relocate the existing utility pole farther away from the roadway where it is less likely to be struck.
• A clear recovery area must be available behind any utility pole that is modified with breakaway hardware so the device has room to perform properly.
• Use of a breakaway design may not be appropriate where an impacted pole might fall on pedestrians or nearby buildings or where fallen wires could interfere with traffic.
• Field installations have demonstrated the device will perform satisfactorily in non- tangent roadway sections.

Funding
Federal-aid funds can be used for the installation of breakaway utility poles on Federal- aid highway projects at up to a 1 00% pro rata share if the State can pay for this work and desires to use its Federal-aid highway funds for this purpose.

The following videotapes and reports are available from the FHWA:

• Breakaway Timber Utility Poles, 1989 -- a 15 minute videotape depicting the procedure used in Kentucky to retrofit existing utility poles with a breakaway device. (Loan, may be reproduced).
• Breakaway Timber Utility Poles, Intro Video, 1995 -- a 1 0 minute videotape introducing the use of breakaway timber utility poles and depicting the procedures used in Kentucky and Massachusetts to install the poles (Loan, may be reproduced).
• Breakaway Timber Utility Pole Installations in Kentucky, 1991 - evaluation report of the Kentucky breakaway timber utility pole project. (Free xerox copy).
• Summary Report: The Breakaway Timber Utility Po/e: A Survivable Alternative (The Massachusetts Experience), 1 993 -- evaluation report of the Massachusetts breakaway timber utility pole project. (Free copy).
• The First installation of Breakaway Timber Utility Poles in Texas, 1995 -- draft evaluation report of the Texas breakaway timber utility pole project. (Free Xerox copy).
• Construction Report, Breakaway Timber Utility Poles, 1996 -- evaluation report of the Virginia breakaway timber utility pole project. (Free Xerox copy).

The detailed evaluation report titled The Breakaway Timber Utility Pole: A Survivable Alternative was prepared and a limited distribution was made in October 1992. A summary report of these evaluations was prepared and distributed to the field in May 1993. For further information on both reports, contact the Project Manager below.

FHWA Contact
General information about breakaway timber utility poles, including copies of the above-mentioned videotapes and reports may be obtained from:

Paul Scott
Federal Highway Administration
HNG-10, Room 3134
400 7th Street, SW.
Washington, D.C. 20590
(202) 366-4104
(202) 366-3988 FAX

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HIGHWAYTECHNET   VIRTUAL EXPO   SAFETY INDEX

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U.S. Department of Transportation
Federal Highway Administration