§ 123-35. Street alignment.

Sight distance, horizontal and vertical curvature and maximum and minimum street grades shall be provided on all streets in compliance with the standards contained in this section.

A. 

Sight distance. Proper sight distance shall be provided with respect to both horizontal and vertical alignments, measured along the center line of the street, at the driver's eye height of 3 1/2 feet, as follows:

	Type of Road	Distance (feet)
	Urban semicontrolled access	500
	Rural semicontrolled access	800
	Collector	500
	Feeder	400
	Residential	300
	Rural	300
	All other streets	200

B. 

Horizontal curvature. Horizontal curves shall be used at all changes in direction in excess of two degrees and shall consider distance, change in grade and alignment. The following standards shall be used:

(1) 

Minimum curve radius at center line.

(a) 

Semicontrolled access: 300 feet.

(b) 

Collectors and feeders: 200 feet.

(c) 

All other streets: 150 feet.

(2) 

Curves and tangents.

(a) 

Long radius curves shall be used rather than a series of shorter radius curves connected by tangents.

(b) 

Reverse curves shall be separated and connected by a tangent of a minimum length of 100 feet, except for local access streets.

(c) 

Curve-tangent relationships shall follow accepted engineering guidelines for safety and efficiency. For example, minimum radius curves shall not be used at the ends of long tangents.

(3) 

Superelevation. Primary and secondary streets shall be superelevated in compliance with accepted engineering standards when a curve radius of less than 600 feet is used.

(4) 

Approaches to intersections. Approaches to intersections shall follow a straight course for a minimum of 100 feet for local access streets. All other streets shall follow a straight course in accordance with accepted engineering standards but in no case less than 100 feet.

C. 

Vertical curvature. Vertical curves shall be used at changes in grades of more than 1%, in compliance with the following requirements:

(1) 

Curve length shall approximate the following for each change of 1%.

(a) 

Primary arterials: 250 feet or as required by the Pennsylvania Department of Transportation.

(b) 

Collectors and feeders: 50 feet.

(c) 

All other streets: 25 feet.

(2) 

The high point or low point on a vertical curve shall be clearly identified on plans and profiles, as appropriate.

(3) 

Over summits or in sumps, vertical curves shall not produce excessive flatness in grade.

D. 

Street grades. All streets shall be graded as shown on the street profile and cross-section plans submitted and approved as a part of the preliminary plan approval process for subdivision and/or land development. Street grades shall comply with the following:

(1) 

Minimum grade for all streets shall be 1%.

(2) 

Maximum grade for streets shall be:

(a) 

Semicontrolled access: 7%.

(b) 

Collectors and feeders: 7%.

(c) 

All other streets: 10% for distances of not more than 1,500 feet.

(3) 

Street grades in excess of 5% should be avoided wherever possible.

(4) 

Street grades shall be measured along the center line.

(5) 

Curve-grade combinations shall follow accepted engineering guidelines for safety and efficiency. For example, minimum-radius horizontal curves will not be permitted in combination with maximum grades.

(6) 

At all approaches to intersections, street grades shall not exceed 3% for a minimum distance of 50 feet.

(7) 

The grade of the outer perimeter of a cul-de-sac turnaround shall not exceed 4%, measured along the curbline.

(8) 

All street grading shall be checked for accuracy under inspection by the Township Engineer.

(9) 

A maximum grade within any intersection shall not exceed 3%.

Amended 8-10-1992 by Ord. No. 384