Admin Order 58-16-01 - Laserfiche WebLink

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4. Streets The maximum street grade permitted in hillside developments is 15 percent, with the following exception: grades in excess of 15 percent, but not more than 20 percent, may be allowed for distances not exceeding 200 feet. Streets grades approaching intersection pedestrian crossings shall transition using standard vertical curves (see Section 2.05.L for pedestrian crossing slopes and Section 4.05.H for vertical curves). 5. Valley Gutters The minimum grade on valley gutters shall be 0.4 percent. K. Gutter Flow To limit the width of storm runoff in street gutters to an acceptable value, regardless of street grade, the maximum length of gutter allowed to carry surface flow is 400 feet or one block, whichever is shorter. When the maximum length is reached, at least one curb inlet or catch basin shall be provided to direct gutter flow to an approved stormwater discharge system. The curb inlet or catch basin shall be located in such a manner that the gutter flow is intercepted before crossing a pedestrian ramp. To propose a greater length of gutter flow, the Project Engineer must submit calculations to substantiate that such a design will achieve the same results. The maximum width of gutter flow shall be 6 feet for streets equal to or greater than 28 feet wide or 4 feet for all other streets. Calculate gutter flows using a 1 year 30 minute storm for computing gutter flow is acceptable. Gutter flow at access ramps shall be a maximum depth of 1 inch. Curb inlets will be required upstream of the ramps to reduce ponding at the ramp. (See Section 2.03 Access Ramps) L. Intersections Intersection design shall meet AASHTO stopping sight distance requirements (SSD) based on the design speed of the facility. In addition to providing the SSD along each street, corresponding sight triangles on each approach leg for an intersection must be provided based on the type of approved intersection control. Local street intersections serving adjoining residential -related traffic shall be designed to achieve sight triangles for uncontrolled intersections as defined by AASHTO, i.e., intersections not controlled by yield signs, stop signs, or traffic signals, unless otherwise approved by the City Engineer. Traffic control devices shall be installed only when warranted by the MUTCD or the Traffic Manual. (See Section 2.07 Traffic Control Devices) Public Improvement Design Standards Manual, 2016 Page 2-22