AASHTO Manual & Handout

A Policy on Geometric Design of Highways and Streets, 1990 by the American Association of State Highway and Transportation Officials. (also known as the "AASHTO Manual") is the commonly recognized resource and standard for road design standards most civil engineers dealing with roadway design. Through incorporation by reference in the Land Division Ordinance and the Public Road Improvement Ordinance, it is the County's basic road design standard. Local fire department access standards reflect the minimum road standard which have precedence over AASHTO standards where appropriate.

AASHTO Handout

There is no substitute for using the actual AASHTO 'Manual', however the Road Department developed a summary paper outlining the basic steps in using the AASHTO Manual to work out road standards for a proposed residential development. Using this handout can serve as a preliminary guide to establishing the standards that may apply to a proposed development. Obviously, related procedures and requirements in respective County Ordinances may impact the final design. Final roadway designs will be designed by a Professional Engineer. This is a five page handout with an appendix. The handout references relevant portions of the AASHTO Manual along with Appendix III of the Tillamook Fire Department Uniform Fire Code Access Requirements (see below).  The AASHTO handout also outlines the basic minimum vehicle configuration that roads are designed for.