20.30 Residential Street Design Criteria

							20.30            Residential Street Design Criteria
1)      Right-of-Way and Pavement Width Requirements:


        Street                           R/W                      Pavement                 Standard
        Classification                   Width                    Width                    Dwg. No.

        2 Lane Minor Local (1)           34                       20 (3)                   C203.80

        2 Lane Minor Rural (1)           34                       20 (3)                   C203.81

        2 Lane Local                     50 (2)                   26 (3)                   C203.82

        2 Lane Rural Local               50 (2)                   26 (3)                   C203.83

        3 Lane Local                     60                       38 (3,4)                 C203.84
        (1)
              The 34' right-of-way width section requires additional drainage and utility
              easements on both sides of the roadway as determined by the Department. It is
              limited to cul-de-sac streets serving not more than 13 lots and loop streets
              limited to 26 lots in "R-1" Zoning Districts.
        (2)
              As provided by Section 1005.180 of the Subdivision Ordinance in any residential
              zoning district where eight (8) or fewer single family lots, including corner lots,
              are proposed on a cul-de-sac street which will not contain sidewalks, a forty (40)
              foot right-of-way is permitted with additional easements as required for drainage
              and utilities.
        (3)
              All of the above designated pavement widths shall be constructed with rolled
              curb with the exception of the following conditions:

                 a) Where subdivisions are approved with commercial lot frontages which require
                    vertical curb.

                 b) Where subdivision Collector streets are designed with vertical curb and
                    restricted access and adjacent lots are served from the internal cul-de-sac and
                    loop streets.

                 c) Where 2 Lane Local streets are approved for improvement with open drainage
                    facilities as shown on Standard Drawings C203.81 and C203.83.

        (4)
              The 38' pavement width shown for 3 Lane Local streets shall be designed in
              accordance with the following lane configurations:

                 a) 3 driving lanes where adjacent residential lots are served from internal
                    cul-de-sac and loop streets.

                 b) 2 driving lanes with 2 emergency parking lanes where adjacent residential lots
                    are served from the collector roadway. However, at major intersections 3 driving
                    lanes with tapers, appropriate pavement joint transitions and posted parking
                    restrictions will be required.


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2)     Pavement Thickness Requirements:


       All Subdivision Streets            Flexible Pavement
       Less Than 30 Feet Wide             2" Type "C" Bituminous Concrete Wearing Surface
                                          7" Type "X" Bituminous Concrete Base
                                          4” Type 5 Aggregate Sub-Base

                                          Rigid Pavement
                                          6" Portland Cement Concrete
                                          4” Type 5 Aggregate Base

                                          Combination Pavement
                                          2" Type "C" Bituminous Concrete Wearing Surface
                                          6" Portland Cement Concrete Base
                                          4” Type 5 Aggregate Sub-Base

       All Subdivision Streets            Flexible Pavement
       More Than 30 Feet Wide             2" Type "C" Bituminous Concrete Wearing Surface
                                          8.5" Type "X" Bituminous Concrete Base
                                          4” Type 5 Aggregate Sub-Base

                                          Rigid Pavement
                                          7" Portland Cement Concrete
                                          4" Type 5 Aggregate Base

                                          Combination Pavement
                                          2" Type "C" Bituminous Concrete Wearing Surface
                                          6" Portland Cement Concrete Base
                                          4" Type 5 Aggregate Sub-Base




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3)     Horizontal and Vertical Alignment Requirements:

                                                                                  Anticipated
Street                                                Centerline                Posted Speed
Classification              Grades (1)                Alignment                       Limit (2)

2 Lane Local                1% Min., 10% Max.,        150' R Min.                25 MPH Min.,
                                                      150' to 75' R
                                                      by special approval
                                                      of Department

3 Lane Local                2% Min., 8% Max.,         15 Degree Max.             30 MPH Min.
                                                      (375' R)


       (1)
             Roadway grades less than 2% or in excess of 8%, require special attention to
             drainage. Refer to Exhibit 20.50-1 for Design Control for Vertical Curves.
       (2)
             Design Speed - On existing roadways design speed shall be the 85th percentile
             speed of motorists on the roadway as established by radar studies, or 5 M.P.H.
             greater than the posted speed limit, whichever is greater. On new roadways,
             design speed shall be 5 M.P.H. greater than the anticipated posted speed limit.




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