Explore the Art and Science of Geometric DesignThe Geometric Design of Roads Handbook covers the design of the visible elements of the road-its horizontal and vertical alignments, the cross-section, intersections, and interchanges. Good practice allows the smooth and safe flow of traffic as well as easy maintenance. Geometric design is covered in d

TRB's National Cooperative Highway Research Program (NCHRP) Report 659: Guide for the Geometric Design of Driveways explores guidelines related to the geometric design of driveways. The report includes driveway-related terms and definitions, an examination of basic geometric controls, a summary of access spacing principles, and detailed discussions of various geometric design elements. Material related to and supporting the contents of NCHRP Report 659, including an extensive review of literature, has been published as NCHRP Web-Only Document 151: Geometric Design of Driveways.

The purpose of this manual is to provide clear and helpful information for maintaining gravel roads. Very little technical help is available to small agencies that are responsible for managing these roads. Gravel road maintenance has traditionally been "more of an art than a science" and very few formal standards exist. This manual contains guidelines to help answer the questions that arise concerning gravel road maintenance such as: What is enough surface crown? What is too much? What causes corrugation? The information is as nontechnical as possible without sacrificing clear guidelines and instructions on how to do the job right.