General. Each street shall be designed to meet the design requirements by use of Appendix E and Appendix F. Newly created right-of-way and cartway width for each interior street classification shall be determined by the proposed use, projected ADT and the intensity of development permitted and existing along each street. Each cartway width shall be based on the travel lane, on-street parking, multi-modal lanes, and gutter width.
Typical Street Layout/Cross-Section | |||||||||
4'+ | 0-8' | 0 or 7' | 2-8' | 9-12' | 9-12' | 2-8' | 0 or 7' | 0-8' | 4'+ |
Side walk | Buf.* | Parking lane | Multimodal lane | Travel lane | Travel lane | Multimodal lane | Parking lane | Buf.* | Side walk |
* Buffer areas and shoulders are encouraged but not required. | |||||||||
A. Travel lanes.
Travel lane width requirements* shall vary according to the average daily trips (ADT). | ||||
Miles Per Hour | Under 400 ADT | 401 to 1500 ADT | 1501 to 2000 ADT | Over 2000 ADT |
15 | 9 ft. travel lane | 10 ft. travel lane | 10 ft. travel lane
| 11 ft. travel lane |
20 | 9 ft. travel lane | 10 ft. travel lane | 11 ft. travel lane | 12 ft. travel lane |
25 | 9 ft. travel lane | 10 ft. travel lane | 11 ft. travel lane | 12 ft. travel lane |
30 | 9 ft. travel lane | 10 ft. travel lane | 11 ft. travel lane | 12 ft. travel lane |
35 | 9 ft. travel lane | 10 ft. travel lane | 11 ft. travel lane | 12 ft. travel lane |
40 | 9 ft. travel lane | 10 ft. travel lane | 11 ft. travel lane | 12 ft. travel lane |
45 | 10 ft. travel lane | 11 ft. travel lane | 11 ft. travel lane | 12 ft. travel lane |
50 | 10 ft. travel lane | 11 ft. travel lane | 11 ft. travel lane | 12 ft. travel lane |
55 | 11 ft. travel lane | 11 ft. travel lane | 12 ft. travel lane | 12 ft. travel lane |
* derived from AASHTO as amended
B. Multimodal Travel Lanes.
(1) Multimodal travel lanes shall be provided for all collector and arterial streets.
(2) Multimodal travel lane requirements shall vary according to the speed of the street.
(a) For a posted speed limit of 26 to 35 miles per hour, 4-foot multimodal lanes shall be provided.
(b) For a posted speed limit of 36 to 45 miles per hour, 6-foot multimodal lanes shall be provided.
(c) For a posted speed limit of greater than 45 miles per hour, 8-foot multimodal lanes shall be provided.
(3) Grates shall be bicycle safe.
C. Curbs, Gutters, and Swales.
(1) Flexibility regarding curbing (type and necessity to provide) shall be permitted as long as the existing storm water management system can accommodate design flows from the proposed drainage system.
(2) Design of curbs, gutters, and swales shall take the following into consideration:
(a) Storm water management;
(b) Road and inlet stabilization;
(c) Soil and/or topography;
(d) Cohesive best management design; and
(e) Pedestrian/handicap safety.
(3) All intersections shall include ADA ramps installed as per PennDOT Roadway Construction Standard RC-67M.
D. Buffer Areas. When buffer areas are provided, signage and street trees shall generally be located within the buffer area of the right-of-way. Buffer areas should be planted with grass, ground cover, or treated with other suitable pervious material. See § 22-523.3 for street tree standards. When buffer areas are provided, buffer areas should be a minimum of 4 feet wide with 8 feet preferred when planted with trees.
E. Rights-of-way.
(1) Centerline of the right-of-way may not always be the centerline of the travel lanes.
(2) Where the right-of-way width of the new street is different than the existing street, a transition area shall be provided, the design of which is subject to Borough approval.
(3) The right-of-way width shall be designed to meet the design requirements by use of Appendix E. Right-of-way widths may change for each street, based on the anticipated future development.
F. Vertical Street Alignments.
(1) Vertical curves shall be used in changes in grade exceeding 1%.
(2) Alignment.
(a) Vertical street and access drive alignments shall be measured along the centerline.
(b) Minimum rate of vertical curvature K shall be as specified below:
Initial Speed (mph) | Curvature, K
1 (ft/%) Crest | Curvature, K1 (ft/%) Sag |
Initial Speed (mph) | Curvature, K
1 (ft/%) Crest | Curvature, K1 (ft/%) Sag |
15 | 3 | 10 |
20 | 7 | 17 |
25 | 12 | 26 |
30 | 19 | 37 |
35 | 29 | 49 |
40 | 44 | 64 |
45 | 61 | 79 |
50 | 84 | 96 |
55 | 114 | 115 |
1Rate of vertical curvature, K = length of curve (L) per percent algebraic difference (A) in the intersection grades (K=L/A) | ||
(3) Grade.
(a) Where the approaching grade is 7% or greater, a leveling area shall be provided within 75 feet of a four-way street intersection on the street of lesser classification, or access drives, or the terminating street at a three-way intersection.
(b) Such leveling area(s) shall have a maximum grade of 4% for a minimum length of 40 feet measured from the intersection of the centerlines.
G. Horizontal Street Alignments.
(1) Horizontal curves shall be used at all angle changes in excess of 2 degrees.
(2) The design of horizontal curves shall be based on an appropriate relationship between design speed and curvature and on their joint relationships with super elevation (roadway banking). (The longer the radius of a curve, the higher the speed through that curve).
(3) Single, long radius curves shall be used rather than a series of curves with varying radii and/or a series of short curves separated by short, straight segments.
(4) Access drives intersections shall be designed to local street horizontal alignment standards.
(5) Determination of minimum horizontal centerline radius*
Initial Speed (mph) | Centerline Radius
1 (feet) No Super elevation | Centerline Radius1 (feet) 4% Super elevation (e max) |
Initial Speed (mph) | Centerline Radius
1 (feet) No Super elevation | Centerline Radius1 (feet) 4% Super elevation (e max) |
15 | 50 | 42 |
20 | 107 | 86 |
25 | 198 | 154 |
30 | 333 | 250 |
35 | 510 | 371 |
40 | 762 | 533 |
45 | 1039 | 711 |
50 | 926 | |
55 | 1190 | |
* derived from AASHTO formula Rmin = V2/15*(0.01e + fmax) 1 Curve radius shall be measured to the centerline of cartways and access drives. | ||
(6) Super elevation in certain conditions may be amended when using AASHTO Exhibit 3-16 as updated.
(7) No street intersection shall be granted at an angle of less than 60 degrees.
H. Street Intersections.
(1) Cul-de-sac/ minor local/ major local streets. A minimum separation of no less than 150 feet between centerlines shall be provided.
(2) Collector streets.
(a) Minor collectors a minimum separation distance of 275 feet between centerlines shall be provided.
(b) Major collectors a minimum separation distance of 300 feet between centerlines shall be provided.
(3) Arterial streets. A minimum separation distance of 600 feet between centerlines shall be provided.
(4) Right angle intersections shall be used. No street intersection modification shall be granted at an angle of less than 60 degrees.
(5) The cartway edge at street intersections shall be rounded by a tangential arc with a minimum radius of 5 feet and a maximum radius of 25 feet. The right-of-way radii at intersections shall be substantially concentric with the edge of the cartway. Curb return radii of 10 -15 feet should be used where high pedestrian volumes are present or the volume of turning vehicles is low. Larger radii should be used when parking or non-motorized lanes are not provided.
(6) Where warranted by a traffic impact study, the Planning Commission or Borough Council may require additional traffic lanes or additional right-of-way to facilitate vehicular turning movements at existing or proposed street intersections within subdivision or land development plans.
I. Sight Distance at Intersections.
(1) Proper sight distance shall be provided at all new streets, access drives, and all driveway intersections in accordance with the latest edition of the Pennsylvania Department of Transportation Design Manual - Part 2, Highway Design (Publication 13), and Section 2.18.F as amended. Sufficient design and plan information shall be submitted with the plan application proving that this minimum standard will be achieved. Such design information shall be sealed by a professional registered in Pennsylvania to perform such design work.
(a) Access drive sight distance based on 10 foot off of edge of cartway, an eye height of 3.5 feet to an object at 3.5 foot height.
(b) Street sight distance based on 15 foot off of edge of cartway, an eye height of 3.5 feet to an object at 3.5 foot height.
(2) All intersections shall be provided with appropriate stop control devices on the lesser classification street or access drive. No sight triangle easements are required when stop control devices are used.
(3) Sight triangle easements shall include the area on each street corner that is bounded by the line which connects the sight or “connecting” points located on each of the right-of-way lines of the intersecting street. The planting of trees, other plantings, signs, and structures exceeding 30 inches in height that would obstruct the clear sight across the area of the easements shall be prohibited.
(a) Arterial streets shall have a clear sight triangle side of 150 feet.
(b) Collector streets shall have a clear sight triangle side of 100 feet.
(c) Local streets, cul-de-sacs, and alleys shall have a clear sight triangle side of 75 feet.
J. New Street Improvements. All street paving must conform to the following specifications unless superseded by a street ordinance or zoning ordinance. All new streets shall be designed to the following cross-sectional specifications. All courses are compacted thicknesses.
(1) The use of recycled materials is strongly encouraged.
(2) Street paving relative strength (design structural number) shall meet 3.5 for all local streets, 3.5 for arterial and collector streets. The design structural number depicts the required strength of the proposed pavement will need to provide. The structural number must be converted to individual layer thicknesses of the pavement.
(a) Structural coefficients for common flexible pavement materials*
Pavement Component | Structural Coefficient | Pavement Component | Structural Coefficient |
Pavement Component | Structural Coefficient | Pavement Component | Structural Coefficient | |
Surface Course: | Crushed Aggregate (CABC) | 0.14 | ||
Superpave 9.5 mm, 12.5 mm, 19 mm, 25 mm (wearing and binder courses) | 0.44 | Crushed Aggregate, Type DG (CABCDG) | 0.18 | |
ID-2, ID-3 (wearing and binder courses) | 0.44 | Aggregate - Bituminous (ABBC) | 0.30 | |
FB-1, FB-2 (wearing and binder courses) | 0.20 | Aggregate - Cement (ACBC) | 0.40 | |
FJ-1, FJ-1C, FJ-4 (wearing courses) | 0.35 | Aggregate - Lime - Pozzolan (ALPBC) | 0.40 | |
Base Course: | Subbase | |||
Plain Cement Concrete (PCBC) | 0.50 | Open Graded Subbase | 0.11 | |
Lean Cement Concrete (LCBC) | 0.40 | No. 2A Subbase | 0.11 | |
Superpave 25 mm, 37.5 mm, base course | 0.40 | Asphalt Treated Permeable Base Course (ATPBC) | 0.20 | |
Bituminous Concrete (BCBC) | 0.40 | Cement Treated Permeable Base Course (CTPBC) | 0.20 | |
* Per current PennDOT standards, Pavement Policy Manual, Publication 242.
(b) Local paving is as follows: 4-inch 2A stone subbase, 3-inch BCBC (bituminous concrete base course), 2-inch binder course, and 1 ½ inch wearing course.
(c) Arterial and collector paving is as follows: 4-inch 2A stone subbase, 5-inch BCBC, 2-inch binder course, and 1 ½ inch wearing course.
(Ord. 614, 5/11/2015)