Sections 64.221 through 64.263 establish the standards for the design of roadways within a public right-of-way which are supplementary to the City's adopted Long-Range Transportation Plan.
Roadway Widths: Reference the Currently Held Valid Thoroughfare Plan of the Rochester-Olmsted Council of Governments for the required roadway widths. The minimum radius to curb face for the roadways in a cul-de-sac shall be at least 40.5 feet. The roadway radius on a cul-de-sac may be increased up to 45 feet to provide additional emergency vehicle turning area on long curvilinear cul-de-sac stem streets where steep grades make it difficult to back fire fighting equipment. The minimum surface width of alleys shall be 18 feet. The right-of-way width for alleys shall be at least 18 feet. The right-of-way width for the radius of a cul-de-sac shall be adequate to accommodate any sidewalk width and boulevard width including area for snow storage, street hardware utilities and boulevard trees.
Table of Design Standards: Table 64.222 identifies for various classes of streets typical design standards to be utilized as a guide for establishing the layout of a street. Modifications to these standards may be approved by the City Engineer under a Type I Review Procedure. The City Engineer may require stricter design standards be applied where it can be shown such higher standards are necessary to protect the public safety.
Table 64.222 Design Standards for Various Classes of Streets
Additional Roadway Design Standards: Roadway Design Standards shall be consistent with the engineering standards adopted by Public Works in conjunction with the development of subdivisions.
Intersections: Insofar as practical, streets shall intersect at an angle of ninety (90) degrees for a minimum of fifty (50) feet from the roadway intersection. In no case shall the angle be less than seventy (70) degrees unless the applicant submits a special intersection design for approval by the city engineer. Intersections having more than four (4) corners shall be prohibited.
Proposed streets which intersect opposite sides of another street (either existing or proposed) shall be laid out to intersect directly opposite each other. The offset between intersections shall be a minimum of two hundred (200) feet measured from centerline to centerline on through streets and as determined by the City Engineer on major streets.
Acceleration, Deceleration and Turning Lanes: Acceleration, deceleration, and turning lanes may be required by the Council along existing or proposed streets when indicated as needed by a Traffic Impact Report or by the Transportation Engineer of the Road Authority. The design of such facilities shall be based on the recommendation of the City Engineer.
Islands: When approved by the City Engineer, islands are permitted within the roadway of a public right-of-way subject to the following considerations: Islands shall be a minimum of 75 square feet in size;
- Islands shall be designed so as to create a natural vehicle path within the travel lane.
- Structures, permanent materials or plantings within the island shall not obscure the visibility of cars entering a cross street for a distance of 20 feet back from the curb face of the cross street, unless a larger setback is needed due to inadequate site distance created by horizontal or vertical curve alignment.
- In designing islands consideration should be given to providing adequate illumination and reflectorization, provision of pedestrian and bicycle needs, provision of adequate access for adjacent properties, and the potential of future signalization or turning lane improvements.
- Public and private maintenance obligations are clearly defined and consistent with City policy.
Trail Thoroughfares and Sidewalks: Trail thoroughfares and sidewalks are a vital element of the City's transportation system -- providing access throughout the City for pedestrians and bicyclists, reducing traffic congestion, facilitating access to the transit system, and reducing emissions from automobiles. Unless otherwise exempted by these regulations, all new development shall provide sidewalk and trail thoroughfare improvements that are consistent with the City's adopted Thoroughfare and Sidewalk, Bike Path and Pedestrian Facilities Plan.
- In addition to trails designated in the City's adopted Plans, the City shall require dedication of trails needed to maintain connectivity between and through subdivisions under each of the following circumstances, except where unique topographical conditions make the trails unfeasible:
- Across any block exceeding 800 feet in length;
- Between lots on a cul-de-sac or dead end street that abut a collector or arterial road. No more than one trail shall be required per cul-de-sac; or
- Across any block exceeding 600 feet in length which abuts a school or park site.
- The Zoning Administrator shall determine minimum trail widths based on the site's natural features and development patterns. Trail easements shall be a minimum of 15 feet in width if adjacent to a street or other public land. The minimum width of a trail easement between the rear or side lot lines of a parcel shall be 30 feet, unless otherwise approved by the Zoning Administrator.
- Sidewalks shall be required along all public streets and shall be designed and constructed in accordance with the City's adopted Long-Range Transportation Plan and Public Works design standards.
- Credits for parkland dedication shall be granted for land which is dedicated for trails for those trails described in the Sidewalk, Bike Path and Pedestrian Facilities Plan and which provide a direct connection to a neighborhood park. Credits for parkland dedication may be granted for land which is voluntarily dedicated for other trails at the City’s discretion. Credits shall not be given for land which is dedicated for trails adjacent to roadways.