A. Location And Arrangement:
1. Whenever a tract to be subdivided embraces any part of a street designated in an adopted town street and highway plan, such street shall be platted in conformance therewith.
2. Street layout shall provide for the continuation of such streets as the department may designate.
3. Whenever a tract to be subdivided is located within an area for which a neighborhood plan has been approved by the commission, the street arrangement shall conform substantially to said plan.
4. Certain proposed streets, as designated by the department, shall be extended to the tract boundary to provide future connection with adjoining unplatted lands.
5. Local streets shall be so arranged as to discourage their use by through traffic.
6. Where a proposed subdivision abuts or contains an existing or proposed major street, the department may require marginal access roads or reverse frontage with nonaccess easements along the major street or such other treatment as may be justified for protection of residential properties from the nuisance and hazard of high volume traffic, and to preserve the traffic function of the major street in other types of developments.
7. Where a subdivision abuts or contains the right of way of a railroad, drainageway, a limited access highway or an irrigation canal or abuts a commercial or industrial land use, the department may require the location of a street approximately parallel to and on each side of such right of way at a distance suitable for appropriate use of the intervening land. Such distance shall be determined with due regard for approach grades, drainage bridges or future grade separations.
8. Streets shall be so arranged in relation to existing topography as to produce desirable lots of maximum utility and streets of reasonable gradient and to facilitate adequate drainage.
9. Alleys are required in all residential, commercial and industrial subdivisions, however, this requirement may be waived by the commission because of lot sizes, topography and other circumstances.
10. Half streets shall be discouraged except where necessary to provide right of way required by the town street and highway plan, to complete a street pattern already begun, or to ensure reasonable development of a number of adjoining parcels. Where there exists a platted half street abutting the tract to be subdivided, the remaining half shall usually be platted within the tract. (1988 Code § 14-3-2)
B. Design Standards:
1. Minimum Required Right Of Way Widths:
a. Major streets and highways, as required by current town, county or state standards.
b. Collector streets, as required by current town standards.
c. Local streets, as required by current town standards; sixty foot (60') full street right of way may be required adjacent to park and school sites.
(1) Cul-de-sac streets shall terminate in a circular right of way forty five feet (45') in radius with an eight foot (8') utility easement around the turnaround. The department may recommend an equally convenient form of turning and backing areas where extreme conditions justify.
(2) Dead end streets will not be approved except in locations recommended by the department as necessary to future extension in development of adjacent lands. In any case, a dead end street extending two hundred feet (200') or more shall be provided by easement a temporary turning circle with a forty foot (40') radius or other acceptable design to accomplish adequate access.
d. Marginal access roads, as required by current town standards.
e. Alleys, when provided, shall be sixteen feet (16') wide where there is single-family residential on both sides; twenty feet (20') wide if abutting commercial, multiple-family residential or industrial districts. Alley intersections and sharp changes in alignment shall be avoided, but where necessary, corners shall be cut off fifteen feet (15') on each side to permit safe vehicular movement. Dead end alleys are prohibited. All half alleys shall have a minimum width of twelve feet (12').
f. Private accessways, as required by town standards.
2. Grades:
a. Maximum:
Collector streets | 7 percent | |
Local streets | 15 percent | All over 12 percent have a maximum length of 600 feet |
Major streets | As determined by the town engineer | |
b. Minimum:
(1) Concrete or asphalt streets with concrete gutters:
Desirable | 0.40 percent |
Minimum | 0.15 percent |
(2) Concrete or asphalt streets without gutters:
Minimum | 0.35 percent |
c. Exceptions: Where rigid adherence to these standards causes unreasonable or unwarranted hardship in design or cost without commensurate public benefit, exceptions may be made by the commission upon review and recommendation of the town engineer.
3. Vertical Curves:
a. Major streets, as determined by the town engineer.
b. When tangent centerlines deflect from each other more than ten degrees (10°) and less than ninety degrees (90°), they shall be connected by a curve with a minimum centerline radius of five hundred feet (500') for collector streets or one hundred feet (100') for local streets.
c. Between reverse curves, there shall be a tangent section of centerline not less than one hundred feet (100') long, unless the radius exceeds six hundred feet (600') on collector streets or two hundred feet (200') on local streets, in which case, fifty feet (50') of tangent shall be required.
d. Streets intersecting a major street shall do so at a ninety degree (90°) angle; intersections of local streets shall not vary from ninety degrees (90°) by more than fifteen degrees (15°).
e. Street jogs with centerline offsets of less than one hundred twenty five feet (125') shall be prohibited except when approved by the town engineer. Under special circumstances where local streets intersect major streets, the town engineer may require minimum centerline offsets of four hundred feet (400').
f. Local streets intersecting a collector street or major street shall have a tangent section of centerline at least one hundred fifty feet (150') in length measured from the right of way line of the major street; except, that no such tangent is required when the local street curve has a centerline radius greater than four hundred feet (400') with the center located on the major street right of way line. Where topographic conditions make necessary other treatment to secure the best overall design, these standards may be varied by the commission upon the recommendation of the town engineer.
g. Street intersections with more than four (4) legs and Y-type intersections where legs meet at acute angles shall be avoided; provisions of T-type intersections for local streets shall be encouraged.
h. At local street intersections, property line corners shall be rounded by circular arc, said arc having a minimum tangent length or radius of twelve feet (12'). A sixteen foot by sixteen foot (16' x 16') triangle shall be provided at each corner of the intersection of two (2) major streets; a fourteen foot by eleven foot (14' x 11') triangle at each corner of the intersection of two (2) collector streets, or as approved the town engineer.
i. Collector streets shall intersect the major streets at the midsection corners or as otherwise approved.
j. Local streets which are primary access to a subdivision shall intersect major streets at the quarter mile corners or as otherwise approved.
k. Marginal access road openings to major streets at a local street intersection shall have a minimum thirty foot (30') wide separation island between the major street traffic lanes and marginal access road, which shall be provided within the major street right of way.
l. Marginal access roads shall not intersect a major street nor a collector street. (1988 Code § 14-3-3)