Case for Variable Design Standards for Secondary Roads

Work has been done to develop a rating system for priority planning use with secondary roads. A key constituent of the rating system is the design standard. It provides the basis for several rating criteria used to evaluate a given road for inclusion in road improvement programs. Therefore, choice of relative design standards can have a significant effect on a rating. Design standards commonly used for secondary roads are similar to those adopted for primary roads with concern for traffic volume and travel speeds. However, this does not necessarily reflect the principal use of these roads as collectors and local access. Emphasis should be on accessibility, and travel speed is less important a factor. Use of lowered design speeds is proposed as one way to economize by avoiding higher costs associated with improved alignment, wider roadways, and flatter ditch slopes. Possible effects on tort liability are reviewed and sample standards are described.