A. Design Standards: Street design standards shall be in accordance with table 1 (subsection S of this section) and as outlined in the following subsections.
B. Right Of Way Width: The right of way shown in table 1 (subsection S of this section) shall be considered the minimum for paving, grading, sidewalks, street utilities, maintenance, safety, and possible pavement widening. When existing or anticipated traffic or arterial streets warrant greater width, such widths shall be required.
C. Lane Widths:
1. Local: The twenty one foot (21') back to back minimum width is for areas which allow for occasional standing vehicles where mandatory off street parking is required. The pavement thickness for residential streets shall be a minimum of five inches (5") of Portland cement concrete or a minimum of five inches (5") of asphalted concrete. The pavement thickness for commercial streets shall be a minimum of six inches (6") of Portland cement concrete or a minimum of six inches (6") of asphalted concrete. Pavement sections for industrial development shall be as recommended by the director of engineering services.
2. Collector:
a. The pavement width of collectors should provide space for two (2) lanes of traffic, where they serve as principal entrance streets to a residential development or for circulation in such a development, and be a minimum width of thirty three feet (33') back to back. Where the density of land use increases, the probability of curb parking and vehicle and pedestrian traffic also increases; therefore, the thirty three foot (33') back to back width shall also be used for multi-family, commercial, or industrial uses.
b. Where provisions are necessary to provide space for two (2) lanes of moving traffic plus accommodation for curb parking, thirty seven foot (37') back to back width is considered necessary to serve this function. The pavement thickness for residential streets shall be a minimum of six inches (6") of Portland cement concrete or a minimum of six inches (6") of asphalted concrete.
D. Right Of Way Widths (Minimum):
1. Local: Fifty feet (50').
2. Collector: Sixty feet (60').
3. Minor arterial: One hundred feet (100') and above.
4. Principal arterial: One hundred twenty feet (120') and above.
E. Type Of Curbs:
1. Local: Six inch (6") barrier curb.
2. Collector: Six inch (6") barrier curb.
3. Where sidewalks are provided, curb ramps with detectable warnings must be provided at each intersection consistent with section 12-8-7 of this chapter.
F. Street Grades:
1. Maximum street grade shall be eight percent (8.0%) (11 percent for local streets) and the minimum grade shall be three-tenths percent (0.3%).
2. Vertical curves shall be required where the algebraic difference in grades is one percent (1.00%) or greater, with a minimum vertical curve length of fifty feet (50').
G. Curb Radii:
1. Curb radius at intersection of residential streets:
25 foot radius | Local to local |
25 foot radius | Collector to local |
30 foot radius | Local to arterial |
30 foot radius | Collector to arterial |
2. Curb radius at intersection of commercial or industrial streets:
30 foot radius | Commercial |
50 foot radius | Industrial |
H. Horizontal Alignment: Horizontal alignment shall provide either a two hundred foot (200') sight distance or a one hundred twenty five foot (125') radius curve, utilizing whichever is greater.
I. Street Grades: Provide proposed grade and existing grade of streets two hundred feet (200') beyond the end of improvements, if the street is to be extended at a later date.
J. Pad Elevations: Show abutting lots and finished contour lines or pad elevations on the plans and profile sheets.
K. Scale: The scale on all plan and profile sheets shall be:
1 inch = 50 feet | Horizontal |
1 inch = 5 feet | Vertical |
L. North Arrow: Show the north arrow and scale on each sheet of all plans.
M. Street Improvement District: Show the street improvement district (SID) number on all sheets. This number is assigned by the director of engineering services.
N. Stationing: Stationing shall be shown on the plan and profile sheets with a minimum of one hundred foot (100') stations on all street and drainage plans. The stationing shall be shown on the plan view with a line running along the centerline of the construction.
O. Curb Line Slope: The slope between the back of the curb and four feet (4') behind the curb shall be plus or minus one-half inch (±1/2") per foot to one inch (1") per foot.
P. Building Line Slope: The slope between the building line and four feet (4') behind the curb shall be less than, or equal to, seventeen percent (17%). Where sidewalks are included, the slope must be adjusted to accommodate this feature.
Q. Subgrade: The subgrade on all streets shall have a minimum AASHTO rating of A-4 or better, as determined by a soils testing laboratory, and shall be compacted to a ninety five percent (95%) standard density. Other soil types shall require sand or lime stabilization treatment as directed by the director of engineering services.
R. Sand Cushion Required: One-half inch (1/2") of sand cushion shall be required on all Portland cement concrete streets.
S. Table 1, Street Design Standards:
Item | Local | Collector | Minor Arterial | Primary Arterial |
Item | Local | Collector | Minor Arterial | Primary Arterial |
Right of way | 50' | 60' | 100' and greater | 120' and greater |
Pavement width (back of curb) | 27' | 33' - 37' | 52' and greater | 52' and greater |
Barrier curb height | 6" | 6" | 6" - 8" | 6" - 8" |
Minimum grade | 0.30% | 0.30% | 0.50% | 0.50% |
Maximum grade | 8.0% | 8.0% | 8.0% | 8.0% |
Cul-de-sac maximum length | 600' | n/a | n/a | n/a |
Minimum radius (right of way) | 50' | n/a | n/a | n/a |
Minimum radius (curb) | 38' | n/a | n/a | n/a |
Minimum centerline radius | 125' | 250' | 465' | 760' |
Sidewalks (minimum width) | 4' | 5' | 5' | 5' |
(Ord. 2009-09, 4-7-2009)