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A. Barring unusual circumstances of or drainage conditions, the following criteria apply to streets (both public and private) and alleys. Any exceptions must be obtained in writing from the City Engineer.
Maximum Longitudinal Grades | |
Travelways under 600 feet in length | 15% |
Travelways over 600 feet in length | 12% |
Cul-de-sac turning areas | 8% |
Minimum Longitudinal Grades | |
Crowned streets | 0.50% |
Inverted streets | 0.50% |
B. Vertical curves are required on local, collector, and arterial streets where the algebraic difference in exceeds 1%, and the minimum desirable vertical curve length is 100 feet. Vertical curves will be designed to meet minimum stopping sight distance.
C. Crowned Streets (see Figure 8). When the street is used as a
landing, the maximum
of the landing area is 2%.
1. The minimum
is 2% for streets with a longitudinal of 0.50% or greater.
2. The minimum
is 3% for streets where a longitudinal less than 0.50% is approved.
3. The maximum
is 4%.
D. Inverted Streets (see Figure 8). When the street is used as a
landing, the maximum
of the landing area is 2%.
1. The minimum cross
for an inverted street is 2% for streets with a longitudinal of 0.50% or greater.
2. The minimum cross
for an inverted street is 3% for a street where a longitudinal of less than 0.50% is approved.
3. Inverted
in excess of 3% may be used only with the City Engineer’s
.
E. Street improvements are required on streets abutting properties subject to rezoning or subdivision platting. The extent of the improvements will be based on the street classification, the amount of traffic projected, soil conditions, and drainage.
F. All street improvement plans must comply with Standard Details for Public Improvements which outlines drafting standards for the preparation of plans.
G. All standard details, specifications, and procedures mentioned in this standard may be obtained at the Office of the City Engineer or the City Clerk.
B. Strip easements may be used along streets for the installation of utilities. (See Figure 15.) With the exception of minor service extensions to individual parcels, all longitudinal utility installations between service points at individual parcels will be located within street rights-of-way. Access between the street and the private property will not be denied unless unsafe conditions exist.
C. All sanitary sewer facilities will be constructed in accordance with current Pima County Regional Wastewater Reclamation Department standards.
When assurances for street, sewer, electric and water utilities, and drainage and flood control improvements are required in conjunction with a subdivision, they will be posted prior to final plat
by the City Engineer or designee. Assurances are to be posted in accordance with Section 8.6.2, Subdivision Improvements and Assurances, of the Unified Development Code.
Clear lines of sight will be maintained along all streets and driveways to assure the safety of motorists and pedestrians.
A. Lines of Sight
1. Lines of sight will not be obscured between 30 inches and six feet through a triangular area adjacent to a driveway, a PAAL, an alley, or a street, where such access ways intersect with another street in a T-configuration. The sight visibility triangle, or sight triangle, consists of three sides that are formed by two intersecting access ways and a line connecting the two.
The first side, or through street side, is drawn parallel to the centerline of the street that is intersected. The second side, or stem side, is drawn parallel to the centerline of the stem street. The line which connects the first two sides, or sight line, is drawn diagonally to the through street. (See Figure 16.)
Where streets meet in a four-way intersection, each street is considered a stem, with the other street considered the through street, for purposes of determining the sight triangle. (See Figure 17.)
2. The datum for the purpose of measuring the limits of the lines of sight (i.e., 30 inches and six feet) is an imaginary plane formed by the intersection of the gutter line (or its approximation) of the through street with the at- centerline (or its approximation) of the stem street.
B. Sight Visibility Triangle Criteria
1. A sight triangle will be maintained on each side of a stem that intersects a two-way through street so that clear sight is provided to vehicles approaching from both the near side (to the driver’s left) and the far side (to the driver’s right) of the stem. Near side means approaching traffic is on the same side of the street as the stem. Far side means approaching traffic is on the opposite side of the street from the stem.
The length required for the through street side of the sight triangle is measured on the side of the stem from which traffic approaches. On one-way streets or streets with median islands (i.e., no opening), only one sight triangle is required on the side of approaching traffic; however, a 20-foot (stem) by 30-foot (curb) pedestrian visibility triangle will be maintained on the opposite side of approaching traffic. (See Figure 16.)
2. If a street is included on the MS&R Plan, both the existing and future sight visibility triangles (based on the MS&R Plan typical cross sections) should be shown. Future sight visibility triangles are to be based upon the MS&R Plan typical cross section for said street. The most restrictive sight visibility triangles will be used unless specifically exempted.
3. The through street side of a sight triangle on a horizontal curve is measured along a chord, as opposed to along the arc. (See Figure 18.)
4. The sight triangle location and dimensions may be adjusted to compensate for unusual circumstances, such as irregular topography or changes, cul-de-sacs, curvilinear or deflected streets, or in other situations acknowledged by the
.
A. The length of the stem side of the sight triangle is 20 feet, measured from a point specified below.
B. The length and location of the through street side of the sight triangle for near side/far side is determined according to the following criteria.
1. On any PAAL or on a street that generates an ADT of 140 or less and intersects a local road, no sight triangle is required. The minimum perimeter yard required in Article 6, Dimensional Standards and Measurements, of the UDC prevails.
2. Where the ADT is greater than 140 but less than 1,001, the through street side is considered a local street in the “Line of Sight Matrix” (Section 10-01.5.3) and is measured at the edge of the nearest adjacent travel lane.
3. Where the ADT is between 1,001 and 12,000 and the street is not designated as an arterial on the MS&R Plan, the through street side is considered a collector street in the “Line of Sight Matrix” and is measured at both the existing and projected (future) face of curb or edge of travel lane. The future face of curb is based on the typical MS&R Plan right-of-way cross section for that street.
4. Where the ADT is 12,000 or more or the street is designated as an arterial on the MS&R Plan, the through street side is considered an arterial street in the “Line of Sight Matrix” and is measured at both the existing and projected (future) face of curb or edge of travel lane.
The future face of curb or travel lane is based on the typical MS&R Plan right-of-way cross section for that street.
5. On any street designated by the MS&R Plan as requiring intersection widening, the midblock MS&R Plan cross section may be used, at the discretion of the City Engineer, for determining the future sight visibility triangles of parcels lying within or adjoining the intersection widened portion of the street right-of-way.
STEM STREET SIDE | THROUGH STREET SIDE | |||
Local | Collector | Arterial | ||
STEM STREET SIDE | THROUGH STREET SIDE | |||
Local | Collector | Arterial | ||
DRIVE/PAAL | Near Side | 185* | 265 | 345 |
Far Side | 110 | 110 | 125 | |
LOCAL | Near Side | 180 | 260 | 340 |
Far Side | 110 | 110 | 125 | |
COLLECTOR | Near Side | 175 | 255 | 335 |
Far Side | 110 | 110 | 125 | |
ARTERIAL | Near Side | 165 | 245 | 325 |
Far Side | 110 | 110 | 125 | |
*Length in Feet
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