This paper outlines the development of the clear zone philosophy, its application to utility offices of state highway agencies, and the findings of a survey of state highway agency utility manuals. A summary is also provided of the many standards and guidelines (prepared by AASHTO, FHWA, and other authoritative bodies) that impact individual utilities in the clear zone. States have pursued widely divergent paths in developing their independent clear zone policies. Forty state utility manuals were reviewed to assess this divergency, and summaries of each state's policies were prepared in tabular and discussion form. Although there were many differences, several concepts and terms were found to be common in many manuals. Examples included the use of terms such as "as near to the right-of-way as practical," and varying lateral clearances based on (a) the presence of curb and gutter, (b) urban/rural locations, and (c) speed limit differences. Greater standardisation is needed, and a national conference focused on the clear zone could initiate this standardisation. At the same time, a training course could be prepared and widely disseminated to increase both understanding and uniformity. The AASHTO Roadside Design Guide (in preparation) was identified as the document that will probably be the most influential in future clear zone policy formulation.
Samenvatting