8.2 Rural Design Elements
8.2.1 General Design Considerations
Freeways in rural contexts are comparable to ground-level urban freeways, and they typically utilize higher design speeds and have wider ROW availability. These freeways are generally comprised of four to six through-traffic lanes, the number being dependent on traffic demand and LOS requirements.
The rural town context is generally not applicable to freeways.
Freeways in rural contexts should provide drivers a smooth and generally level ride as these are generally designed for high speed conditions. Rural contexts offer fewer physical constraints, allowing profiles to be generally flat. Gradual adjustments of grade improve sight distance and driver performance, and they also improve the general appearance of the roadway by eliminating sharp elevation changes which may interfere with drivers.
Because freeways in rural areas typically have a wider ROW, wider medians can be utilized to increase driver safety and freeway appearance. Common median width for these freeways range from 50 to 100-ft, with wider medians of 150-ft or more allowing for independent alignments for opposing travel directions. Construction of wide medians also provides space for additional travel lanes that may be needed to handle future traffic volumes.
Rural freeways do not present a large need for frontage roads, as these roads will typically serve only small properties or connection to local roads. Because of this, frontage roads for freeways in rural areas are generally short and sparse.