This paper describes research conducted for the city of Huntsville, Alabama, to design and implement a program for treatment of poles located in the roadside clear zone. Many standards and guidelines apply to poles beside the roadway. For example, three primary resources were reviewed for traffic signs, four were reviewed for traffic signal posts, and several others were found to cover utility poles and support equipment. Field investigations were conducted at the sites of 385 pole collisions. Lateral clearance from the roadway and other data were collected for statistical analysis. These data revealed several interesting characteristics associated with urban pole collisions. For example, about 90% of the accidents occurred within 10 ft of the pavement edge, and the relationship between accidents and distance was linear in this range. The presence of a curb had a significant effect upon the lateral distance to the object, while the presence of a horizontal curve did not. Curves were overrepresented in pole accidents by a 6 to 1 ratio. Drivers were three times more likely to have collisions on the outside of horizontal curves than on the inside. Wet pavement was not a significant factor in these collisions. The research staff used the results of the field investigation to provide a series of detailed recommendations for retrofitting a clear zone program to existing poles. At the same time, the literature review provided the basis for recommendations for ordinances and operating procedures to cover future poles in the clear zone.
Samenvatting