A.
Guidelines.
(1)
All highways shall be designed in accordance
with the latest edition of a Policy on Geometric Design of Highways
and Streets, published by AASHTO, except that all specific requirements
stated in this article shall take precedence over the AASHTO guidelines.
B.
Applicability.
(1)
Unless otherwise stated, this article is written
for rural or suburban roads but shall be used as applicable for other
classes of highways.
C.
Continuation of streets into adjacent property.
(1)
Streets shall be arranged to provide for the
continuation of principal streets between adjacent properties where
such continuation is necessary for convenient movement of traffic,
effective fire protection, efficient provision for utilities and particularly
where such continuation is in accordance with the Town plan.
(2)
If the adjacent property is undeveloped and
a street must dead-end temporarily, the right-of-way and the improvements
must run to the property line. A temporary circular turnaround shall
be provided on all temporary dead-end streets.
A.
The Highway Superintendent shall determine and designate
into which of the four following classifications each proposed street
falls on the basis of one or more of the defining criteria. The Highway
Superintendent may delegate to the Planning Board the authority to
designate the class for any highway that is part of a subdivision
or site plan also reviewed by the Planning Board.
[Amended 11-14-2002 by L.L. No. 5-2002]
B.
Major or through highway.
(1)
The proposed highway is the direct and logical
continuation of an existing highway that carried 500 or more heavy
and light vehicles during a twelve-hour period as shown on the latest
traffic count if heavy vehicles (trucks) are more than 10% of the
design hour traffic volume. At least half of the trucks are anticipated
to be at or near the legal maximum weight.
(2)
The proposed highway creates a shorter and more
convenient through traffic artery so that it can be reasonably expected
that traffic will be diverted from other major highways to such an
extent that it will reach at least 500 cars in 12 hours within two
years after opening.
(3)
The proposed highway could logically be expected
to become a major highway because of future construction or other
foreseeable circumstances.
C.
Commercial or industrial highway.
(1)
The proposed highway is in an area zoned for
commerce or industry.
(2)
The proposed highway is on or so close to the
dividing line between a residential and a commercial or industrial
area that it may reasonably be expected to carry a substantial volume
of heavy vehicles.
(3)
The proposed highway creates a shorter and more
convenient route between a commercial or industrial area and a major
traffic artery.
(4)
The proposed highway for any other reason may
be expected to carry a substantial volume of commercial or industrial
traffic.
D.
Rural or suburban highway (local road). (This classification
is intended to cover the majority of subdivision streets.)
[Amended 11-14-2002 by L.L. No. 5-2002]
(1)
The proposed highway shall not be, or be reasonably
expected to become, a major or commercial highway.
(2)
The proposed highway shall be a dead end, loop
or other minor highway within a residential development.
(3)
The proposed highway is not, or cannot reasonably
be expected to become, a continuation or extension of a major or commercial
highway. Should such be the case, the proposed highway shall take
the classification of the highway of which it is a continuation or
extension.
(4)
The proposed highway does not, or cannot reasonably
be expected to, carry a substantial volume of traffic.
E.
Minor local road. (This classification is intended
to cover only certain streets in cluster subdivisions or CRD Developments.)
[Added 11-14-2002 by L.L. No. 5-2002]
(1)
The proposed street shall not be, or be reasonably
expected to become, a rural or suburban highway (local road).
(2)
The proposed street shall only serve residential
properties in a cluster subdivision, or a CRD Development.
(3)
The proposed street shall be no longer than
2,500 lineal feet.
(4)
The proposed street shall not carry, nor be
reasonably expected to carry, more than 1,000 cars or other vehicles
per twenty-four-hour timeframe.
(5)
The proposed street shall be expected to accommodate
pedestrian traffic in more densely settled areas, and must provide
sidewalks, pathways or other off-road pedestrian accommodations, and
street trees.
(6)
Within CRD Developments and cluster subdivisions,
the Planning Board shall also have discretion to approve one or more
private roads. Such roads may include those serving small groups of
dwellings. Private roads providing primary access to dwelling units
shall have a right-of-way width of not less than 42 feet, and shall
meet the other standards of minor local roads. Private roads may also
include rear service lanes, subject to the following: (1) pavement
width shall be not less than 18 feet; (2) a rear service lane may
not be a dead-end road; (3) a rear service lane may not provide the
primary access to a dwelling; (4) any garages deriving access from
the rear service lane shall be set back at least 25 feet from the
edge of pavement. No private roads may be approved unless the Board
is satisfied that the road will be permanently maintained by a homeowners'
association or other similar entity.
F.
The roadway right-of-way (ROW) width shall be a minimum
of 50 feet for rural or suburban highways and minor local roads and
a minimum of 60 feet for major or through highways and commercial
or industrial highways.
[Amended 11-14-2002 by L.L. No. 5-2002]
(1)
Where regrading extends beyond the fifty-foot
ROW, the developer shall include all regrading outside of the right-of-way
in permanent grading easements.
(2)
Where there is no defined or dedicated ROW,
the subdivider or developer shall deed to the Town, at minimum, all
land within 25 feet of the mean center line of the existing "road
by user" when so requested by the Highway Superintendent.
(3)
Where sidewalks are planned, the ROW width may
be increased by five feet per side to provide a buffer strip.
A.
All highways other than minor local roads shall be
designed so that finished tangent grades will not be less than 1%
nor more than 10%. Minor local roads shall be designed so that finished
tangent grades will not be less than 1% nor more than 12%.
[Amended 11-14-2002 by L.L. No. 5-2002]
B.
Every change in grade shall be effected with a vertical
curve of sufficient length to ensure adequate stopping sight distance
and to provide for a smooth transition.
[Amended 11-14-2002 by L.L. No. 5-2002]
(1)
All streets other than minor local roads shall
be designed so that the length of any crest vertical curve shall be
a minimum 30 times the algebraic difference of the tangent grades,
but not less than 100 feet.
(2)
For minor local roads, the length of any crest
vertical curve shall be a minimum 15 times the algebraic difference
of the tangent grades, but not less than 100 feet.
(3)
All streets other than minor local roads shall
be designed so that the length of any sag vertical curve shall be
a minimum 40 times the algebraic difference of the tangent grades,
but not less than 100 feet.
(4)
For minor local roads, the length of any sag
vertical curve shall be a minimum 30 times the algebraic difference
of the tangent grades, but not less than 100 feet.
(5)
The maximum length of any vertical curve shall
not exceed 143 times the algebraic difference of the tangent grades.
C.
When an existing road is extended, the new road profile
shall match the existing tangent slope or continue the existing vertical
curve as applicable.
D.
There is no minimum tangent length requirement between
vertical curves, either successive or reverse.
[Amended 11-14-2002 by L.L. No. 5-2002]
A.
For all streets other than minor local roads, two
tangent sections of a roadway shall be connected with a horizontal
curve of at least three-hundred-foot radius, measured at the center
line. The minimum curve length shall be 200 feet.
B.
For minor local roads. two tangent sections of a roadway
shall be connected with a horizontal curve of at least two-hundred-foot
radius, measured at the center line. The minimum curve length shall
be 100 feet.
C.
For all classifications of highways:
(1)
Superelevation shall be used only when approved
by the Highway Superintendent and the Town Engineer.
(2)
When an existing road is extended, the new road
alignment shall match the existing tangent section or start or continue
a horizontal curve.
(3)
There shall be a minimum one-hundred-foot tangent
section between reverse curves. "Broken back" curves may be used only
if the segments of the same hand are separated by a minimum two-hundred-foot
tangent section.
A.
At an intersection, the major road grade should normally
be limited to 3%, but in special cases the Town Engineer or Highway
Superintendent may authorize up to an eight-percent grade, with adjustments
to design factors, particularly as affecting sight distance along
the road and corner sight distance.
[Amended 11-14-2002 by L.L. No. 5-2002]
B.
When a new roadway intersects another new roadway, the mainline roadway profile shall be designed in accordance with Figure II-4.
C.
Normally, the grade-line of the major road should
be carried through the intersection, and the grade-line of the minor
road should be adjusted. Such a design requires a transition of the
crown of the minor road to an inclined cross section at its junction
with the major road. Drainage shall be carefully designed to prevent
ponding and minimize sheet flow across the pavement.
D.
Intersections of a major road by other roads shall
be at least 800 feet apart, center to center. A distance of at least
150 feet, center to center, shall be maintained between offset intersections
on all classes of streets. At-grade intersections shall have no more
than four legs on all classes of streets.
[Amended 11-14-2002 by L.L. No. 5-2002]
E.
Within 40 feet of an intersection, the minor road
center line shall be approximately at right angles, but not less than
70°, to the major road. Where a minor road intersects a major
road that is on a horizontal curve, the minor road center line shall
be tangent and radial to the major road for a minimum of 40 feet.
F.
The ROW lines at a road intersection shall be connected
by a minimum twenty-five-foot radius curve, tangent to each leg.
G.
For more complex intersections, such as those involving
sidewalks, islands, curved alignment, etc., the AASHTO guidelines
shall be followed to the greatest possible extent.
A.
Wherever a temporary or permanent dead end is allowed on a subdivision road, a circular turnaround shall be constructed. There shall be a notation on the plat that the land outside the road right-of-way shall revert to abutters whenever the road is continued. See Figure II-5.
B.
All turning circles shall have grades between 2% and
5%, unless otherwise approved by the Highway Superintendent or the
Town Engineer, and shall assure properly directed drainage flow into
the catch basin(s).
[Amended 11-14-2002 by L.L. No. 5-2002]
C.
Surface treatment shall be of the same type as the
road leading to the circle, as shown on Figures II-1, II-2, and II-3,
and must be approved by the Highway Superintendent.
D.
For major or through highways, and commercial or industrial
highways, the radius of the cul-de-sac at the right-of-way line shall
be 65 feet and the radius of the paved area shall be 50 feet.
[Added 11-14-2002 by L.L. No. 5-2002]
E.
For rural or suburban highways (local roads) and minor
local roads, the radius of the cul-de-sac at the right-of-way line
shall be 50 feet and the radius of the paved area shall be 40 feet.
[Added 11-14-2002 by L.L. No. 5-2002]
A.
Actual sight distance shall be determined by roadway
speed limits, grades, pavement surface and related criteria. An adjustment
shall be made for the effect of grades, per the AASHTO guidelines.
B.
At intersections (including driveways) or along curves,
where required by the Highway Superintendent or the Town Engineer,
the developer shall provide the Town with a deeded sight easement
which shall remain free of any plantings over one foot in height and
free of any buildings, structures or other obstructions, in order
to maintain clear, unobstructed sight distance. Tree overhang shall
be trimmed and maintained to a line at least eight feet above the
level of the roadway.
C.
A minimum three-hundred-foot sight distance shall
be provided along a curve for a 30 mph design speed, except for a
minor local road.
[Amended 11-14-2002 by L.L. No. 5-2002]
D.
Stopping sight distance shall be measured from a point
on the center line of the approaching lane of the minor road or driveway
12 feet behind the projected edge of the roadway of the major road,
to a point on the center line of the approaching lane of the major
road, to a point on the center line of the approaching land of the
major road. The height of eye and height of object shall both be assumed
to be 44 inches above the road pavement.
E.
Visibility at intersections. Within the triangular
area formed at corners by the intersection of street center lines,
for a distance of 75 feet from their intersection and the diagonal
connecting the end points of these lines, visibility for traffic safety
shall be provided by excavating, if necessary. Nothing in the way
of fences, walls, hedges or other landscaping shall be permitted to
obstruct such visibility.
F.
On a corner lot in any residential district no fence,
wall, hedge or other structure or planting more than 31/2 feet in
height shall be erected, placed or maintained within the triangular
area formed by the intersecting street lines and a straight line joining
said street lines at points which are 30 feet distant from the point
of intersection, measured along said street lines.