The purpose of this article is to establish basic road design standards that meet the requirements of Section 9-1.102 and seek to balance the necessity for safe roadways which provide adequate immediate and long-term circulations while simultaneously causing the least modification to the native state of lands. Adherence to the standards contained in this article, or innovative equivalents thereof, will be reviewed favorably to the degree that they achieve, in the opinion of the Town, this balance.
Roadway designs are not mutually exclusive from the improvements to the lots and/or parcels which they serve and, therefore, must insure continuity in planning and engineering design so that the transitional development of raw land to improved rural neighborhoods is accomplished with minimal disruption of the natural terrain throughout all development stages.
(§ 1, Ord. 572, eff. February 18, 2018)
The following factors shall be considered in the design of streets in all subdivisions:
(a) 
Size and shape of lots;
(b) 
Topography;
(c) 
Traffic volume;
(d) 
Aesthetics and preservation of natural attributes and native trees;
(e) 
Driveway access;
(f) 
Fire protection and emergency vehicles;
(g) 
Drainage;
(h) 
Roadway related structures.
(§ 1, Ord. 572, eff. February 18, 2018)
(a) 
The minimum right-of-way width for all public and private roads, except fire or emergency roads, shall be 60 feet.
(b) 
The minimum right-of-way for a fire or emergency road shall be determined upon the recommendation of the City Engineer based upon a consideration of the expected use, terrain, vegetation, soils and all other factors pertaining to the width of the road. The minimum clear width of Fire Department access roads shall be 20 feet.
(c) 
Where a cut or fill road slope is outside the right-of-way of a road, a slope control easement may be required of sufficient width to permit the maintenance of the slope upon the recommendation of the City Engineer.
(d) 
Exceptions can be made only when one-way streets are permitted or where the City Engineer recommends that the standard width as applied to the particular case would be impractical or would create unnecessary detriment to the land.
(e) 
The right-of-way width of a road may be increased to include the following:
(1) 
Sufficient space for cuts and fills unless slope easements are provided in addition to the uniform right-of-way width. Where cuts attain 10 feet in height, or fills attain eight feet in height (maximum cut and fill permitted), the right-of-way slope easement shall clear the top of cut or the toe of fill slope by at least six feet;
(2) 
Space for all required street improvements such as pavement, gutter, paths, pathways, bikeways, shoulders and drainage structures, green infrastructure and appurtenances;
(3) 
Space for all public utilities; and
(4) 
Space for safe driveway approaches.
(f) 
Cul-de-sac rights-of-way shall terminate in turnaround areas having a minimum radius of 50 feet measured at the property lines. This right-of-way area will also be required for a "hammerhead" as depicted in the City standards.
(g) 
At the intersection of two or more streets, the property lines shall be rounded with a curve having a radius of not less than 30 feet.
(§ 1, Ord. 572, eff. February 18, 2018)
All roads shall be so designed as to grades, intersections, and approaches that traffic hazards are minimized in keeping with the accepted traffic engineering standards and the satisfaction of the City Engineer.
(a) 
Split Level, One-Way Streets. Split level, one-way streets shall be designed to take advantage of the natural contour of the land so as to provide the best possible access to building sites, reduce cuts and fills and establish desirable grades. When, in the opinion of the City Engineer, the use of split level, one-way streets will result in a more efficient use of the existing terrain, will minimize the scarring effects of development on the hillsides, retain existing vegetation, and their use is justified by detailed engineering studies, they shall be considered by the Planning Commission. There shall be provided standard emergency pullout parking stalls, adequate to contain two vehicles, each of which shall be eight feet wide by 50 feet in length.
(b) 
Cul-de-Sac Streets. Cul-de-sacs normally shall not be more than 1,500 feet, measured along the centerline of the cul-de-sac, from the center of the turning circle at the end of the cul-de-sac to the center of the first intersection from the cul-de-sac, unless topographic conditions justify the use of longer cul-de-sacs. In cases where the length of the cul-de-sac is greater than 1,000 feet, there shall be provided standard emergency pullout parking areas, adequate to contain two vehicles. The space shall be eight feet wide by 50 feet in length, not to exceed intervals of 500 feet on straight sections, and may be required at each end of every blind curve.
Turning circles at the end of cul-de-sac streets shall have a roadway radius of not less than 32 feet, except that in mountainous or hillside areas the roadway radius may be reduced to 22 feet. Alternative designs such as hammerheads for turning or reversing direction may be used in lieu of the turning circle, as depicted in the City standards and approved by the City Engineer.
(c) 
One-Way Loop Streets. Where one-way loop streets are used, emergency pullout areas shall be provided at intervals not to exceed 500 feet on straight sections, and may be required at each end of every blind curve. Each emergency pullout area shall measure eight feet in width by 50 feet in length.
(d) 
Wherever pullout areas are required, the design shall consider the combining of the pullout areas with driveway accesses of the adjoining proposed lots immediate to the pullout area. Where such a design application is utilized, the pullout area shall not be used to satisfy the off-street parking requirements as defined in Section 10-1.601 of the Municipal Code.
(e) 
Divided or Stepped Roadways.
(1) 
Where the terrain is of such character due to slope, existing tree density and vegetation that a normal two-lane road will result in removal of mature trees and scarring of the hillside, the subdivider shall consider a divided or "stepped" roadway. Cross connections or ties may be required to be constructed at intervals not to exceed 500 feet. The width of right-of-way for a divided or stepped roadway shall be sufficient to include a minimum pavement width of 12 feet in addition to shoulders, surface longitudinal drainage with appurtenances, cut and fill slopes, and pathway improvements if in the opinion of the Planning Commission pathways are necessary, and such pathways are in accordance with the General Plan and its elements, and the approved Master Pathway Plan of the Town.
(2) 
Divided or "stepped" roads shall be separated by a cut or fill slope not less than two horizontal to one vertical. Special devices will be considered in lieu of this slope requirement where the City Engineer determines that the engineering design of the separating device is satisfactory and not in excess of three-quarter vertical to one horizontal, provided that the entire device can support landscaping over 80% of its surface area, and that the vertical facade of all or any part of the device shall not be in excess of three feet in height.
(3) 
Emergency pullout areas shall be provided approximately at 500 foot intervals, to be located mid-way between crossovers, when provided, on straight sections and may be required at each end of every blind curve. Each emergency pullout area shall be adequate to contain one vehicle. The space shall be eight feet in width by 25 feet in length.
(4) 
Wherever pullout areas are required, the design shall consider the combination of the pullout area with driveway accesses of the adjoining proposed lots, immediate to the pullout. Where such a design application is used, the pullout area shall not be used to satisfy the off-street parking requirements.
(f) 
Dead-End Roads. Proposed dead-end roads shall be extended to within one foot of the boundary lines of the land to be divided in all cases where, in the opinion of the Commission, such extension is necessary for traffic circulation and the coordination of the layout of the proposed subdivision with existing developments, or the advantageous future development of adjacent property. The above one-foot strip shall be deeded to the Town.
(g) 
Emergency Access Routes. The subdivider may be required to improve and dedicate to the Town emergency access routes, including rights-of-way and improvements, from the ends of cul-de-sacs or any other advantageous topographic point along the street right-of-way.
(h) 
Adjoining Roads. Every subdivider shall bring the alignment and the widths of rights-of-way of all existing roads adjoining the subdivision into the conformity with this article, the General Plan and its elements, and the adjoining street system of the Town, or as recommended by the City Engineer. The subdivider shall offer to dedicate to public use such rights-of-way as are required for the present and future widening of all public rights-of-way contiguous to the subdivided property.
(§ 1, Ord. 572, eff. February 18, 2018)
The design of all streets shall incorporate horizontal and vertical curves adequate to provide a maximum of vehicle safety, including proper sight distance and safe stopping distance, in addition to the design speed. The minimum horizontal curve centerline radius on a local winding hillside road shall be 100 feet and the minimum length of the vertical curve shall be 100 feet. Collector and arterial streets shall be designed to incorporate vertical and horizontal curves greater than the above minimums for local streets in order to provide for the increased traffic flow and vehicle speeds on collector and arterial streets. The paved width of splitlevel or one-way streets shall be increased as necessary to provide for safe movement of traffic in the vicinity of sharp curves. A minimum horizontal curve centerline radius of a winding hillside collector or arterial road shall be not less than 400 feet. In flat areas, local streets shall have a centerline radius as long as possible. Suitable tangents shall be provided wherever practicable between reverse curves.
(§ 1, Ord. 572, eff. February 18, 2018)
All grades and curves shall be designed to provide proper sight distance and safe stopping distance in relation to the design speed. All roads shall have at least five-tenths percent grade. Grades shall not exceed 12% on collector and arterial roads, 15% on any other street, or 20% if no other method is practicable because of topographical conditions or other exceptional conditions, and if the design is consistent with good engineering practices. Streets having grades between 10 and 15% shall in no case exceed 500 feet in length measured along the centerline. Streets having grades between 16 and 20% shall be not more than 300 feet in length between points of intersection of adjacent grade lines.
Grades in excess of 20% shall not be permitted. The grades of all streets shall be kept as low as possible, bearing in mind the advantageous development of the property.
(§ 1, Ord. 572, eff. February 18, 2018)
The angle of intersection between streets, roads, avenues or lanes shall not vary more than 20 degrees from a right angle. Driveways shall intersect roadways at an angle of 90 degrees to the greatest extent possible. These requirements may be modified by the City Engineer.
(§ 1, Ord. 572, eff. February 18, 2018)
Unless otherwise approved by the City Engineer and concurred with by the Planning Commission, the centerlines of any two streets, roads, avenues, or lanes entering upon opposite sides of any street, road, avenue, or lane shall intersect at the same point or at points separated by not less than 150 feet.
(§ 1, Ord. 572, eff. February 18, 2018)
Reserve strips controlling the access to public ways shall not be approved unless such strips are necessary for the protection of the public welfare and/or of substantial property rights and shall only be approved when the complete control and disposal of the land and all of the uses comprising such strips of land are placed completely within the exclusive control of the City Council.
(§ 1, Ord. 572, eff. February 18, 2018)
Private roads are permitted provided the following requirements are met:
(a) 
The road is not a through road and there is clear assurance it will remain so in the future. It cannot remain private if it becomes a through road.
(b) 
All lots served by the private road are included in a road maintenance agreement which runs with the land and is acceptable to the City Attorney.
(§ 1, Ord. 572, eff. February 18, 2018)