Streets shall be designed in accordance with Guidelines for Design of Local Streets and Roads (Publication 70), as amended, of the Pennsylvania Department of Transportation; Dover Township Construction Specifications, latest edition; and the following criteria, whichever is more stringent:
A. Streets shall be laid out according to the requirements shown in Table 22-7-1; however, additional street width may be required as determined by the Board to insure public safety and convenience in accordance with the purposes of this Chapter.
B. Where a subdivision abuts or contains an existing street, the developer shall be required to:
(1) Provide sufficient additional right-of-way and cartway widths to meet the above standards.
(2) Mill and provide new wearing course to centerline of existing cartway.
(3) Provide leveling course/milling to correct street cross slope to current standards (2% minimum).
C. Street Construction. Streets must be constructed to the grades and dimensions drawn on the plans, profiles, and cross-sections submitted by the applicant and approved by the Board of Township Supervisors. Before paving the street surface, the applicant must install the required utilities and provide, where necessary, adequate stormwater drainage for the street acceptable to the Supervisors. The pavement base, wearing surface, and shoulders must be constructed according to Dover Township construction specifications.
D. Curves (Horizontal). Where connecting street lines deflect from each other at any one point, the line must be connected with a true, circular curve.
(1) The minimum radius of the center line for the curve must be as shown in Table 22-7-1.
(2) Straight portions of the street must be tangent to the beginning or end of curves.
E. Curves (Vertical). Vertical curves shall be used in changes of grade when the algebraic difference exceeds 1%. Crest and sag curves shall be designed in accordance with the following:
Minimum Rate of vertical curvature, Ka (ft/%) | |||
Posted Speed Limit (mph) | Design Stopping Sight Distance (ft) | Crest | Sag |
Minimum Rate of vertical curvature, Ka (ft/%) | |||
Posted Speed Limit (mph) | Design Stopping Sight Distance (ft) | Crest | Sag |
15 | 80 | 3 | 10 |
20 | 115 | 7 | 17 |
25 | 155 | 12 | 26 |
30 | 200 | 19 | 37 |
35 | 250 | 29 | 49 |
40 | 305 | 44 | 64 |
45 | 360 | 61 | 79 |
50 | 425 | 84 | 96 |
55 | 495 | 114 | 115 |
60 | 570 | 151 | 136 |
F. Slope of Banks Along Streets. The slope of banks along streets measured perpendicular to the street center line shall be no steeper than the following:
(1) One foot of vertical measurement for 3 feet of horizontal measurement for fills.
(2) One foot of vertical measurement for 2 feet of horizontal measurement for cuts.
G. Crown. The crown shall be as required in Dover Township construction specifications.
H. Shoulders. Shoulders shall be provided as required in Table 22-7-1 and shall be constructed of the same materials as the cartway.
I. Intersections. Intersections shall be designed in accordance with the criteria shown in Table 22-7-2, and the following:
(1) Clear Sight Triangle. Proper sight lines must be maintained at all street intersections. Measured along the center line, there must be a clear sight triangle of 75 feet (150 feet for arterial streets) from the point of intersection of the two street lines, and no buildings or, obstructions or plantings which could grow higher than 3 feet above the grade of the center line of the streets shall be permitted in this area. Where not located within a public right-of-way, the area shall be recorded as an easement on the plat at the time of subdivision and/or land development.
(2) Maximum grade within any intersection shall not exceed 4% in any direction, and approaches to any intersection shall follow a straight course for the length specified in Table 22-7-2.
J. Radius corners or diagonal cutoffs must be provided on the property/right of way lines substantially concentric with, or parallel, to the cord of the curb/paving radius.
K. Sight Distance. Sight distance must be provided with respect to both horizontal and vertical alignment. Passing sight distance and stopping sight distance shall comply with the minimum requirements of PennDOT Publication 70, based on highway classification and speed limit.
L. Alleys and Service Drives. The following standards shall apply to the design and location of alleys and service drives:
(1) Alleys shall not be permitted in residential developments except by the permission of the Board of Township Supervisors. All buildings or other structures adjacent to any alley must comply with the side or rear yard setbacks from the alley right-of-way line as included in the appropriate district regulations in the Zoning Ordinance [Chapter 27].
(2) Alleys or secondary service drives serving nonresidential establish ments are required unless other provisions for service are provided.
M. Lots Abutting Arterial Roads. In a subdivision or land development abutting an arterial street, one of the following may be required:
(1) The frontage shall be reversed so that the lots contiguous to such roadways will front on a minor collector or local street, with an additional lot depth of 20 feet as an easement exclusively for planting and screening to be provided by the developer along the arterial street.
(2) A service road shall be provided along such arterial street and shall be separated from it by a landscaped berm. The berm shall have a minimum bottom width of 20 feet, a maximum slope of 2 to 1 and a minimum height of 3 feet.
(3) Such other means of separating through and local traffic and of providing a suitable buffer shall be provided as the Board of Supervisors may determine to be appropriate.
(4) The side yard of a lot abutting a designated arterial roadway shall be increased by an additional width of 20 feet as an easement exclusively for planting and screening to be provided by the developer along the arterial street.
(Ord. 2011-05, 3/14/2011, § 704)