Economic and Safety Considerations for Establishing Minimum Lateral Obstacle Clearance Policies for Utility Facilities in Nebraska Urban and Suburban Areas
Ronald Faller, Jim Holloway, Edward Post, Syed Ataullah
The Nebraska Department of Roads (NDOR) is reviewing the Federal Highway Administration’s (FHWA’s) policy for lateral obstacle clearance or offset for utility facilities on curbed sections along new or reconstructed municipal state highways in urban areas. The FHWA requires that utility appurtenances such as fire hydrants, utility poles (electrical distribution or transmission), light poles or luminaires, gas pipeline structures, etc., be located at a 6 ft minimum lateral offset from the back of the curb for new or reconstructed municipal state highways. Since accidents involving utility poles are associated with one of the higher rates of accident severity, a considerable reduction in both accident frequency and accident severity could be obtained by specifically studying and analyzing utility pole installations. Basic street lighting and fire hydrants were also emphasized in the study. The cost-effectiveness methodologies selected for use in the study were presented in Federal Highway Administration report number FHWA-IP-86-9, “Selection of Cost-Effective Countermeasures of Utility Pole Accidents—User’s Manual,” by Zegeer and Cynecki; and the American Association of State Highway and Transportation Officials’ (AASHTO) publication entitled, “Roadside Design Guide” 1988 Computer models were developed for both methodologies. The first, “UPACE,” was intended for use with utility installations having multiple appurtenances in a line or a row, for example, a line of power poles; the second, “ROADSIDE,” was intended for use with single utility installations such as fire hydrants. Seven actual safety improvement projects were analyzed with “UPACE” to evaluate current standards and their effectiveness, obtain actual field data, and validate various parts of the computer model. After the site-specific analyses were completed, it was evident that a more detailed breakdown was needed for the various typical utility installations. Accordingly, general site analyses were performed with “UPACE” for various typical utility installations such as street lighting, power distribution, power transmission, and breakaway light and utility poles. A benefit-to-cost ratio methodology was used as the basis for the results and conclusions. General site analyses were also performed with “ROADSIDE” for various typical single utility installations such as utility poles, light poles, and fire hydrants; and for one actual site, a gas installation. Some of the key questions which were evaluated were (1) whether it was cost-effective to relocate a line of poles, and at what lateral distance it became cost-effective, (2) whether the relocation of poles was more cost-effective than modification of existing poles to be breakaway, (3) whether it was cost-effective to relocate a single utility installation, such as a power, pole, light pole, and fire hydrant, and at what lateral distance it became cost-effective, (4) whether the relocation of a single utility installation was more cost-effective than modification of the installation to be breakaway, and (5) whether the 6 ft minimum lateral offset was adequate.
Highway Safety, Roadside Safety, Lateral Obstacle Clearance, Roadside Appurtenances