2018-06-25-minutes-public-works-study-session

Home Browse Search

Intersection location, spacing, and design are fundamental to the management of access and preservation of capacity provided for in the roadway design. The functional classification of each roadway addresses the appropriate level of access control for that roadway. For proposed access approaches onto any road, the intersections created are classed into two types, roadways and driveways. Roadway intersection design criteria, as defined in this section, will be used for all proposed access approaches that meet the criteria for classification as a roadway under Roadway Classifications, KCC 12.03. Driveway design criteria will be used for residential and commercial driveway approaches as defined under Driveway Access, KCC 12.04 Article IV When an intersection with three or more lanes is proposed, a traffic engineering analysis along with a signing, striping, and traffic channelization plan shall be completed by a professional engineer licensed in the State of Washington. The adequacy of each design criteria provided in this section below shall be addressed by an appropriate engineering analysis. These criteria are minimum guidelines only and may be modified according to traffic volumes and mix, topography, design speed, design vehicle requirements, and other conditions. The design of intersections shall follow criteria of AASHTO Policy on Geometric Design of Highways and Streets and other appropriate design guidelines. The following specific criteria shall be used to design the location and geometry of roadway intersections in Kittitas County: A. Location of new arterial and collector streets shall be in accordance with the WSDOT Design Manual. All new intersections will have a minimum straight tangent length prior to beginning any curves in accordance with the WSDOT Design Manual. C. The design of intersections on arterial streets shall be in accordance with WSDOT Design Manual. D. Separation of intersections shall be in accordance with WSDOT Design Manual. E. Street intersections shall be laid out so as to intersect as nearly as possible at right angles. Sharp angled intersections shall be avoided. The angle of an intersection on new construction shall not be less than 75 degrees or more than 105 degrees. Intersection skew angles that exceed this range must be well justified and shall be subject to approval by the County Engineer. Profile grades for all roads (public or private) intersecting onto a county road (existing or proposed) . shall be designed and constructed so that adequate entering sight distance is available at the intersection. On sloping approaches at an intersection, landings shall be provided with grade not to exceed three percent slope for a distance of 30 feet approaching any arterial or 20 feet approaching a collector or local access road. These approach slope requirements shall be met to the maximum extent feasible. If it is impossible to meet the requirement, the justification must be well documented and shall be subject to approval by the County Engineer. Title 12 Kittitas County Code I Draft No. 5 — Working Draft for Adoption 6/12/2018