[Code 1999 §410.090; Ord. No. 479 Art. III, 11-9-1995]
A. No
preliminary subdivision plat shall be approved unless it conforms
to the following minimum standards of design:
1. Streets — relationship to adjoining streets. The arrangement of rights-of-way in a subdivision shall provide
for the continuation of the existing streets or rights-of-way in adjoining
areas, unless the Commission deems such continuation undesirable for
reasons of topography or design. Where subdivision streets or rights-of-way
adjoin other streets or rights-of-way, the width thereof, where practical,
shall be at the same or greater width or width sufficient to adequately
serve the subdivision of the existing street or rights-of-way in the
subdivision but shall not be of less width than hereinafter provided.
2. Projection of streets. Where, in the opinion of
the Commission, it is desirable to provide future street access to
adjoining areas, the streets and rights-of-way in the subdivision
shall be extended by the provision of a right-of-way for street purposes
from the end of the pavement to the property line of the subdivision.
If deemed necessary by the Commission, any such dead-end street shall
be provided with a temporary turnaround. The street arrangements shall
not be such as to cause hardship to owners of adjoining property in
platting their own land and providing convenient access to it. However,
except to avoid landlocking property, nothing herein shall be construed
to require that private streets in one (1) subdivision shall provide
access to adjacent lands.
3. Classification of streets and widths of rights-of-way. All streets shall be classified as either highway, thoroughfare,
collector, or local in accordance with their use and function, the
standards of public safety and topographic conditions. The classification
of each street designated on a plat shall be reviewed by the Commission
and revised as necessary to conform with the standards of these regulations.
4. Streets shall have the following right-of-way widths.
a.
|
Street Type and Purpose
|
Right-of-Way Minimum Width
|
---|
|
Thoroughfare
|
80 feet
|
|
Collector streets
|
60 feet
|
|
Local streets
|
50 feet
|
|
Alleys
|
20 feet
|
b. Subdivisions adjacent to existing deficient streets or roads shall
provide additional right-of-way to meet the minimum width requirements
set forth.
c. A subdivision located on only one (1) side of an existing street
or County road shall provide one-half (½) of the required right-of-way
width, measured from the centerline of the existing roadway.
5. Intersections.
a. Streets shall intersect, as nearly as possible, at right angles.
b. Street curb intersections shall be rounded by radii of at least twenty-five
(25) feet. When the smallest angle of street intersections is less
than sixty degrees (60°), the Commission shall require curb radii
of greater length.
6. Curves and grade changes in streets — horizontal.
a. A tangent of at least one hundred (100) feet long shall be introduced
between reversed curves on major and collector streets.
b. Where there is a deflection angle of more than ten degrees (10°)
in the alignment of a street, not including intersection with any
street, a curve with a radius adequate to insure safe sight distance
shall be made. The minimum radii of curves shall be:
|
Street Type
|
Minimum Curve Radius
|
---|
|
Thoroughfares
|
350 feet
|
|
Collector
|
250 feet
|
|
Local
|
100 feet
|
7. Street grades and elevations.
a. No street grade shall be in excess of:
|
Street Type
|
Street Grade
|
---|
|
Thoroughfares
|
Seven percent (7%)
|
|
Collector
|
Ten percent (10%)
|
|
Local
|
Twelve percent (12%)
|
|
Except as otherwise approved by the Commission because of adverse
topographic conditions.
|
b. All curbing shall be designed to provide for surface water drainage
from the surrounding area, buildings and pavement. The minimum grade
shall be not less than one-half of one percent (.5%).
c. The Commission shall not approve streets which will be subject to
frequent or repeated inundation or flooding.
8. Service roads. Where the subdivision abuts on or
contains an existing or proposed major street, the Commission may
require marginal access streets to be provided to avoid lot frontage
on major streets.
9. Street jogs. Street jogs with centerline offsets
of less than one hundred (100) feet are prohibited.
10. Cul-de-sacs. Cul-de-sacs shall be no longer than
five hundred (500) feet and shall terminate in a circular open space
having a radius at the outside of the pavement of at least fifty (50)
feet and a diameter at the outside of the right-of-way of at least
one hundred twenty (120) feet. In the event the topography dictates
excessive grades for side streets, a cul-de-sac greater than five
hundred (500) feet in length, such extension shall require approval
of the Planning and Zoning Commission.
11. Street names.
a. Proposed streets which are continuations of, or in alignment with,
existing named streets shall bear the names of such existing streets,
unless otherwise approved by the Commission.
b. The name of a proposed street which is not in alignment with an existing
street shall not duplicate the name of any existing or platted street.
c. All names of streets proposed by the subdivider shall be approved
or disapproved by the Commission.
12. Alleys. Alleys shall be provided to give access
to the rear of all lots used for commercial and industrial purposes
except where other provisions are made for access. Alleys may be required
in certain residential subdivisions by the Planning and Zoning Commission.
13. Blocks.
a. Length. Block lengths shall not exceed four hundred
(400) feet in length. If the topography justifies a departure from
the stated maximum length, such variance shall require approval of
the Planning and Zoning Commission. Excess grades on intersecting
streets may be considered justification.
b. Width. Blocks shall be at least wide enough to allow
two (2) tiers of lots of minimum lot depth. The Commission may approve
double frontage lots which would otherwise front on a major street
or where topographic or other tract conditions prevent single frontage
design. Where double frontage lots are permitted, a twenty (20) foot
landscaped buffer shall be provided and access from the "rear" street
prohibited.
14. Pedestrian ways. Pedestrian ways may be required
across blocks which exceed nine hundred (900) feet in length, to connect
dead-end streets, or to provide access to parks, schools, shopping
areas, or similar facilities. If a pedestrian way is required, a ten
(10) foot right-of-way shall be set aside with a four (4) foot wide
pavement, and at a grade no steeper than fifteen percent (15%) unless
steps of adequate design are provided.
15. Lots.
a. Each lot shall be free from flooding. No lot shall be impractical
of improvement due to steepness of terrain, dangerous soil conditions,
storm water collection, or other adverse natural physical conditions.
Side lot lines shall be right angles to street lines and radial to
curved street lines where practical. The size, shape, and orientation
of lots shall be designed to provide desirable building sites properly
related to topography, natural features, streets and land uses.
b. Residential lots served by public sewers shall have a lot area of
not less than seventy-five (75) feet wide by one hundred (100) feet
in depth.
c. The minimum lot area of residential lots proposed to be served by
individual private wells shall be as determined by the Commission
and the Missouri Department of Natural Resources in accordance with
the factors of soil conditions and the proposed sewage disposal system.
d. Remnants of land, containing less area than herein required and not
designated and accepted for utility or public purposes, shall be permitted.
e. Where property is proposed for development for commercial uses, the
subdivider shall design a layout providing for an overall or unified
development, and where possible, avoid the platting of individual
lots for each business establishment.
f. When property is to be developed for industrial uses, consideration
will be given to a flexible lot, street, and utility arrangement in
order to allow for the needs of particular industries.
16. Utility and drainage easements.
a. Except where alleys are permitted or required, there shall be utility
easements at least twelve (12) feet in width along rear lot lines.
Where deemed appropriate, utility easements shall be provided along
the side lot line or across lots.
b. Storm water easements and drainage rights-of-way shall be required
as deemed necessary. The subdivider shall provide an adequate easement
and facilities to prevent flooding or erosion along each side of the
stream. This easement shall be for any flood abatement purpose as
determined by the Commission and any local or State agencies so concerned.
The subdivider may be required to enlarge, straighten, or clear the
existing drainage channel at time of construction to prevent altering
of downstream or upstream drainage.