[Zoning Order Art. 16, Div. III, 4-2-2008]
The design standards related to the rural, rural cluster, mixed use, mixed use addition, large lot, suburban, infill and industrial development patterns, as set forth in Article VII which are minimum standards, shall be applicable to the subdivision of property as governed by this Article, provided that the design standards may be modified as set forth in Section 400.1230(E).
[Zoning Order §16.340, 4-2-2008]
A.
Block Length. In general, block lengths are determined by
intersecting streets and shall be provided at intervals that will
serve cross traffic adequately and that meet existing streets or existing
design practices in the area. Maximum block length shall be as provided
by the design standards for the development pattern associated with
the zoning district for the proposed development or the development
pattern the County, pursuant to Section 400.2160(5), determines is
the most appropriate development pattern:
B.
Block Width. The width of the block shall normally be sufficient
to allow two (2) tiers of lots of appropriate depth.
[Zoning Order §16.350, 4-2-2008]
B.
Excessive
depth in relation to width shall be avoided. The depth to width ratio
should not exceed three to one (3:1), except on lots of over forty
thousand (40,000) square feet in areas where topographic conditions
would suggest that a higher ratio would lead to a more desirable subdivision
design. No lot shall be less than one hundred (100) feet in depth,
unless in a planned development. (The definition of depth shall include
the following language: any part of the lot less than thirty-five
(35) feet in width shall not be included when measuring the depth
of the lot.)
C.
Side
lot lines should be at right angles to street lines or radial to curved
street lines.
D.
Lots
in one- and two-family subdivisions with double frontage shall not
have access to both front and rear streets. Double frontage lots should
be avoided when possible.
E.
Each lot in a subdivision shall have a minimum lot width for the appropriate zoning district as established in Table 5-2, Section 400.1660 or the plan in a planned development. Each lot on a cul-de-sac or eyebrow shall have a minimum lot width measured along a line drawn tangent to the front building line equal to the minimum lot width for other lots in the subdivision, except that lot width at the front property line shall be sufficient to accommodate a driveway and roundings within the lot frontage.
F.
Lots
should not derive access from County or State-maintained streets.
For lots over forty thousand (40,000) square feet in area, where topographic
or other conditions would suggest that an alternate design would lead
to a more desirable subdivision design, direct access may be approved
by the County.
G.
Except
in planned districts, access to a County or State-maintained street
shall not be allowed for one- and two-family developments when a major
local access street, local access street or local access alley is
available.
[Zoning Order §16.360, 4-2-2008; Resolution 1-14-2010A
Exh. A, 1-14-2010; Ord. No. 10-0145 §§1 — 2, 2-18-2010;
Ord. No. 17-0158, 2-14-2017]
A.
The arrangement, character, extent, width, grade and location of
all streets shall be considered in their relation to existing and
proposed streets, to topographical conditions, to public convenience
and safety and to the proposed uses of land to be served by these
streets. The following standards shall apply:
1.
Arrangements of streets shall conform as nearly as possible
to the official Master Plan as adopted by the County and a Jefferson
County Roadway Master Plan and providing for the extension of such
streets. Street layouts should provide stub right-of-way connections
to the edge of the development to adjacent sites, so that street patterns
can be extended to future development, where topography allows and
future anticipated land uses would benefit. Wherever practical, streets
shall connect with streets already dedicated on adjacent subdivisions
or be a reasonable projection of streets in the nearest subdivided
tracts.
2.
Cul-de-sacs and eyebrows will be permitted where topography or other conditions justify their use and provisions shall be made for adequate traffic circulation. Except as provided in Article VII, cul-de-sacs shall not be longer than fifteen hundred (1,500) feet, including a turnaround at the closed end. A cul-de-sac on an access street should have a minimum outside curb radius of thirty-nine (39) feet and a minimum right-of-way radius of fifty (50) feet.
3.
An adequate number of points of ingress to and egress from a
development shall be provided to ensure smooth traffic flow into and
out of all portions of the development[1], sound traffic engineering and public safety. The determination
of an adequate number of points of ingress and egress shall consider
all relevant factors including, but not limited to, the following
factors:
a.
Residential Subdivisions. Points of ingress to and egress from
the subdivision shall be required in accordance with the following
table. Each required point of ingress to and egress from the subdivision
shall be located so as to best serve the traffic generated by the
subdivision. Streets shall be designed to maintain a balanced distribution
of traffic throughout the subdivision and among all points of ingress/egress.
No more than sixty-five percent (65%) of the traffic shall flow to
one (1) major local access or local access street or to one (1) entrance
if two (2) or more entrances are required.
|
Minimum Subdivision Accesses Required
| |
|---|---|
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Number of lots
|
Minimum number of ingresses/egresses
|
|
0 — 49
|
1
|
|
50 — 99
|
1 with median
|
|
100 — 299
|
2
|
|
300 and above
|
per approved development plan (no less than 3)
|
b.
Non-Residential Subdivisions. The adequacy of the number of
points of ingress to and egress from non-residential subdivisions
shall be determined as a part of and based on the consideration of
the development plan for the proposed development, where required,
or otherwise imposed as a condition of approval of the preliminary
plat. If a development plan is required, the plat for that development
shall show the same number of ingress and egress points as are shown
on the approved development plan. All approvals of the preliminary
plats shall be conditioned upon the final plat being consistent with
the development plan with respect to the number of points of ingress
to and egress from the subdivision.
c.
General Factors.
(1)
Traffic Accumulation. The level of traffic using
each point of ingress to and egress from the subdivision should not
exceed the level of traffic that the type of street proposed is designed
to accommodate. See Jefferson County Roadway Master Plan, when completed.
(2)
Access For Emergency Vehicles. The points of ingress
to and egress from the subdivision should be adequate to ensure that
emergency vehicles can gain access to all proposed uses within the
subdivision whenever necessary.
(3)
Intersection of points of ingress to and egress
from the subdivision with streets abutting the subdivision. The impact
of injecting traffic from the proposed subdivision into the existing
street network shall be mitigated by location, design and control
measures consistent with the standards of traffic engineering.
(4)
Access To County Or State-Maintained Street.
(a)
The proposed subdivision or each phase of the proposed
subdivision with fifty (50) or more lots shall have access to a County
or State-maintained street within or abutting the proposed subdivision,
except as provided in Section 400.5410(3)(a).
(b)
Where a proposed subdivision or each phase of a
proposed subdivision does not abut a County or State-maintained street,
where access is proposed through easements or private rights-of-way
leading from the County or State-maintained street, such easements
or rights-of-way shall be improved to the applicable street standards
required in this UDO.
(5)
When a subdivision is a portion of a larger area planned as a phased and related development, a sketch plan of the entire development shall be submitted with the preliminary plat of the area first to be subdivided. The sketch plan shall include the requirements in Section 400.5170(E)(1) of this UDO.
(6)
When a final plat of a subdivision covers an area
that is less than that covered by the related preliminary plat, the
determination of the adequacy of points of ingress and egress shall
be made independently for, and considering the cumulative effect of,
each proposed phase of the development or subdivision, as the case
may be.
[1]
Editor's Note: Table 404.1.2(8) is included as an attachment
to this Chapter.
4.
The County may require additional information as needed to determine
accordance with the UDOs purposes and the County's public health,
safety and general welfare, including a comprehensive traffic study
that determines the effects of the proposed development on the street/highway
system and the points in that system where any adverse impacts are
no longer significant.
5.
Where the plat to be submitted includes only part of the tract
intended for development by the subdivider, a tentative plan of a
proposed future street and roadway system, including all points of
ingress to and egress from the subdivision, for the unsubdivided portion
should be prepared and submitted by the subdivider, as part of the
requirement for preliminary plats.
6.
When a tract is subdivided into larger than required minimum
size building lots or parcels, such lots or parcels should be so arranged
as to permit the continuous location and opening of future streets
and appropriate resubdivision.
7.
Streets shall be laid out so as to intersect as nearly as possible
at right angles, except where topography or other conditions justify
variations.
9.
Limited Access.
a.
Commercial Subdivisions. If a commercial subdivision abuts or
contains an existing or proposed arterial street, the Planning Commission
may require frontage roads or other treatment (such as reverse frontage
lots with access control and screening provisions along the rear property
line, deep lots with rear service alleys, etc.) as may be necessary
for adequate protection of residential properties to afford separation
of through and local traffic and to provide visually safe, attractive
roadways.
(1)
Frontage Road. A frontage road is a street adjacent
to the boundary of the arterial street right-of-way that has:
(a)
Right-of-way width of fifty (50) feet minimum;
(b)
Pavement width of twenty-eight (28) feet minimum;
and
(c)
Frontage road intersecting a cross street. Where
the right-of-way of a frontage road intersects a cross street, the
frontage road right-of-way shall be located a minimum distance of
two hundred (200) feet from the curb or shoulder of the arterial street,
with due consideration given to future grade separation and with access
prohibited between the arterial street and the frontage road.
b.
Residential Subdivisions.
(1)
If a residential subdivision abuts or contains
an existing or proposed arterial street, the Planning Commission may
require frontage roads or other treatment (such as reverse frontage
lots with access control and screening provisions along the rear property
line, deep lots with rear service alleys, etc.) as may be necessary
for adequate protection of residential properties to afford separation
of through and local traffic and to provide visually safe, attractive
roadways.
(2)
Individual lots shall not directly access the frontage
road.
10.
In portions of a subdivision containing single-family, duplex
residential subdivisions or multi-family uses, access to a lot shall
not be allowed unless in a planned district from a County or State-maintained
street if access from a major local access or local access street
is available.
11.
Alleys, where provided, that are not the primary access to the
lot shall not be less than fourteen (14) feet wide (two-way) and ten
(10) feet (one-way). Intersecting alleys shall have corner cutoffs
of at least twenty (20) feet on a side. Dead-end alleys shall be avoided
wherever possible.
12.
Curb Radii. See Section 400.2580, Street Standards — Curb Radii. Any curb radii onto County or State maintained streets shall be subject to the approval of the County or State.
13.
Visual Clearance.
a.
Proper lines of sight shall be maintained at all intersections and driveways. Traffic on secondary streets shall stop or yield at intersections with equal or higher classification streets. A "sight triangle" is the area that shall have an unobstructed view from the stopping point to all points of a required distance three (3) feet above the roadway along the centerline of the existing roadway. The distance of the unobstructed view shall be based on the design speed of the intersecting street. Article VII provides a design speed table and a schematic of the required visual clearance. No building or other type of visual obstruction shall be placed, erected or maintained within the sight triangle. Street trees are allowed within the sight triangle, provided that they do not have any foliage, limbs or other obstructions between three (3) and ten (10) feet above ground level and are not closer than thirty-five (35) feet to the intersecting pavement edges.
b.
Nothing in this Section shall be construed to allow placement
of objects in the street right-of-way.
14.
Reserved strips of land that control or limit access at the
terminus of streets are prohibited. Street layouts may provide right-of-way
connections to the edge of the development adjacent to parcels of
land that may develop in the future so that the street pattern can
be maintained. Where the right-of-way is extended to the edge of the
property boundary, a joint maintenance agreement with the adjacent
property owner where the right-of-way is extended may be required.
The County may require paving within the extended right-of-way to
the property boundary.
15.
All streets and related improvements shall be designed in accordance with the standards set forth in Article VII. In the absence of a pavement construction standard in this UDO, the standards shall be in accordance with the St. Louis County Standard Specifications for Highway Construction and the Design Criteria for the preparation of improvement plans in effect as of the date of the adoption of this UDO, as stated in Section 400.110. Alternative methods of pavement design may be approved only by the Planning Commission, with a recommendation from the Public Works Department.
16.
The Planning Commission may require streets to be dedicated
to public use and constructed to the standards required herein to
provide appropriate circulation.
17.
The above street standards may be altered, based upon a comprehensive traffic design study, adhering to Article VII requirements, that demonstrates that safe, efficient and appropriate traffic circulation shall occur. The traffic study may be submitted by the subdivider and shall include any appropriate documentation that demonstrates the adequacy of the proposed traffic circulation system. Final approval of any alterations shall be made by the Planning Commission and shall only occur after review and comment by the Planning Division and the Public Works Department.
18.
The following standards shall apply to street names and signs:
a.
To avoid duplication and confusion, the proposed names of all
streets shall be approved by Jefferson County "911" prior to the names
being assigned or used.
b.
Whenever a new street is constructed along the approximate alignment
or extension of an existing street, its name shall be the same as
that of the existing.
c.
Street name signs, as approved by the Planning Commission, shall
be erected by and at the expense of the subdivider.
d.
Regulatory traffic control measures will be designed and implemented
by the subdivider as approved by the Planning Commission.
e.
The Governing Body of the subdivision/development shall maintain
traffic control measures.
[Zoning Order §16.370, 4-2-2008]
B.
On
cul-de-sac streets serving single-family development, where sidewalks
are required only on one (1) side of the street the sidewalks need
not extend around the bulb of the cul-de-sac. Where sidewalks are
not required or where they are required only on one (1) side of the
street, the subdivider is encouraged to install sidewalks elsewhere
in the subdivision.
C.
No
sidewalks are required on service road facilities.
D.
When
a sidewalk is required on one (1) side of a street, the sidewalk should
be placed on the opposite side of the street from the water line.
[Zoning Order §16.380, 4-2-2008]
A.
All
proposed subdivisions/developments shall have easements adequate for
the installation and maintenance of utility facilities. Utility easements
shall be at least ten (10) feet wide, five (5) feet on each side of
the lot line and shall be located along the rear or front lines as
needed for proper utility placement. When necessary, side utility
easements shall be at intervals of no more than three hundred (300)
feet along a block face.
B.
Stormwater
drainage easements may be required if necessary for proper drainage
within and through the subdivision/development. In addition, easements
may be required to cover those areas subject to inundation by floodwaters,
when a subdivision/development is proposed along a lake, river, stream
or surface drainage course.
C.
Where
a cut or fill for a street extends beyond the limits of the right-of-way,
the subdivider shall provide a slope easement of sufficient area and
limits to permit the construction and maintenance of the slope.
D.
Utility
easements shall connect with easements established on adjoining properties
as recommended by the utility authority.
E.
Additional
easements for pole guys should be provided at the outside of turns.
Where possible, lot lines shall be arranged to bisect the exterior
angle so that pole guys will fall along the side lot lines.
F.
The
developer shall provide all easements required by the public utilities.
All proposed subdivisions/developments shall have easements adequate
for the installation and maintenance of utility facilities.
G.
Placement of utility easements in residential subdivisions shall follow the Jefferson County street lighting standards in Section 400.5450.
H.
Existing
easements that are recorded and/or platted and streets that conflict
with the proposed use or plat must be vacated prior to final plat
approval.
I.
Utility
companies have established a joint trench agreement in Jefferson County.
This agreement is shown in the following schematic.
 |
[Zoning Order §16.390, 4-2-2008]
A.
All
areas to be reserved for or dedicated to public use shall be indicated
on the preliminary plat. Information shall be provided for when, if
and in what manner these areas will be dedicated to or acquired by
the appropriate agency.
B.
For
areas to be dedicated to the County, the recommendations of the official
Master Plan shall be considered.
C.
All
streets, alleys, sidewalks, easements and other public sites, when
approved, shall not thereafter be substantially changed without the
approval of the County Council following recommendation of the Planning
Commission and the County Public Works Director, provided vacations
may occur as permitted within this Article.
[Zoning Order §16.400, 4-2-2008]
A.
The
subdivider shall install street lights in all subdivisions, multi-family
developments, manufactured housing parks and non-residential subdivisions/developments
at each intersection of two (2) major local access/local access streets
and in all subdivisions/developments at each intersection of a major
local access/local access street with a County or State-maintained
street.
B.
Each
lighting source shall have a height of not less than sixteen (16)
feet above grade and shall have a minimum standard six thousand eight
hundred (6,800) lumen output. Maximum initial illumination level five
(5) feet from the base of the light source shall be no greater than
three (3.0) foot-candles but no less than thirty-five hundredths (.35)
foot-candles.
C.
All
street lighting shall be designed and maintained to avoid unnecessary
illumination of residential interiors.
D.
All
electric lighting shall be controlled automatically by programmed
devices, photo electric cells or the like. Street lighting shall be
on from dusk to dawn.
E.
Street
light standards shall be located no closer than eighteen (18) inches
from the street pavement. Where sidewalks are required, street light
standards shall be located between the sidewalk and street pavement.
[1]
Editor’s Note: Former Section 400.5460, Fencing and
Fall Protection Requirements, which derived from Zoning Order §16.410,
4-2-2008, was repealed 1-4-2016 by Ord. No. 16-0100.
[Zoning Order §16.420, 4-2-2008]
A.
For
any subdivision having privately maintained streets and approved after
the effective date of these regulations, the subdivider shall construct
a sign at all entrances to the subdivision, within fifty (50) feet
of the entrance, clearly stating that public maintenance ends. This
sign shall be in a manner acceptable to the Public Works Department.
B.
These
signs shall be installed where they are easily visible to anyone entering
the subdivision and maintained in good order by the subdivider until
the property owners' association is formed and then thereafter by
the property owners' association. The minimum size for each sign shall
be twelve (12) inches high by eighteen (18) inches wide, with three
(3) inch high letters. The contrast between the background and the
lettering shall be sufficient to make the sign easily read.
C.
Disclosure. Record plats shall include a note that states
that streets are to be maintained by the property owners of the subdivision
and not by Jefferson County.
[Resolution 1-14-2010A Exh. A, 1-14-2010; Ord. No. 10-0145
§§1 — 2, 2-18-2010; Ord. No. 20-0406, 9-29-2020]
A.
Creation
of an obstruction, including a gate, which controls or limits access
or vehicular movement on a street that is dedicated for public use,
is allowed, provided:
1.
The obstruction is shown on the approved preliminary plat;
2.
The obstruction shall conform to Section D103.5, Appendix D, of the
International Fire Code;
3.
At the location of the obstruction, an area must be provided to allow
vehicles to turn around in accordance with Figure D103.1 and Table
D103.4, Appendix D, of the International Fire Code;
5.
Provide the specifications for the proposed obstruction.
6.
The gate or obstruction may not impact public traffic circulation
or impair access to property off-site to the subdivision or development;
or impair access to or from public facilities, including schools,
parks and libraries; or otherwise impair the response time of emergency
vehicles.
[Zoning Order §16.440, 4-2-2008]
The County is authorized, as deemed necessary, to prepare administrative
guidelines (that do not substantively change the purpose and intent
of the UDO) to augment, implement and provide further details and
examples of methods and manners of complying with the minimum design
standards of this Article, to clarify the intent of this Article and
to assist County staff, the Planning Commission and the County Council
in evaluating whether a proposed subdivision complies with the minimum
design standards. No later than fourteen (14) days in advance of the
effective date of the administrative guideline, the Director shall
provide a copy of the administrative guideline to each member of the
County Council. Upon receipt of the administrative guideline, a majority
of the County Council may request a review of the administrative guideline
and may approve all or a portion of such guidelines by resolution.
Any portion reviewed by the County Council and not so approved shall
not take effect. If the County Council does not request review, the
administrative guidelines shall take effect on the date set by the
Director. All administrative guidelines that take effect in this manner
and have not been previously adopted by the County Council shall be
adopted by the County Council, by resolution, annually. Should the
County Council adopt administrative guidelines, those guidelines will
be presented to the Planning Commission.
