[Ord. No. 39-1998, § 3.1, 12-1-1998]
(a) 
The purpose of the street design standards in this article is to ensure that public right-of-way improvements implemented in the City provide for safe and efficient vehicular and pedestrian traffic, including handicap access; provide for minimum longterm maintenance costs of public improvements; protect the environment, the public and abutting landowners by providing the necessary controls for stormwater runoff, soil erosion and siltation, and groundwater; and protect the public health and safety.
(b) 
These standards provide for flexibility, having the design fit into the surroundings, attempting not to waste the City's valuable natural resources, etc. Some previous limitations have been relaxed by providing strict guidelines on how to deal with those situations without loss of quality.
(c) 
If the road or street is to be totally owned and maintained by a private entity and located entirely on the property of that private entity, and the posted speed is not more than 25 miles per hour, and side access is only permitted by curb cuts to parking areas, and no parking is allowed anywhere on the roadway pavement, then the ADT requirements can be waived by the planning board in the approving of a roadway section.
[Ord. No. 39-1998, § 3.2, 12-1-1998]
Water shall be removed from any base material to protect the roadway surface from frost damage. All subbase surfaces must be sloped to drain, with no pools, puddles, or trapped water that would be internal to the base material.
[Ord. No. 39-1998, § 3.2.1, 12-1-1998]
The horizontal alignment of streets proposed in all subdivisions shall conform to the following standards:
(1) 
When centerline tangents deflect from each other, except at intersections, they shall be connected by a centerline curve having a minimum radius of 110 feet for residential streets, 175 feet for collector streets and 75 feet for lanes.
(2) 
Between reverse curves, where the radius of one or both curves is less than 200 feet, there shall be a tangent section of centerline not less than 50 feet in length. There shall be no superelevation in such cases.
(3) 
Streets intersecting an arterial street shall do so at a ninety-degree angle. All streets intersecting collector or residential streets shall not vary from 90° by more than 15°.
(4) 
At street intersections, the right-of-way lines shall be rounded by a circular arc having a minimum radius of 20 feet. A greater radius may be required for streets intersecting at an angle other than 90°.
(5) 
Dead-end streets shall be provided with a turnaround having an outside paved roadway diameter of 112 feet and a right-of-way diameter of not less than 130 feet. Where any subdivision includes a dead-end street, not designed to be so permanently, the subdivider shall make temporary provisions for a turnaround as the City engineer may deem necessary. For a circular turnaround, applicants are encouraged to utilize larger diameter turnarounds with green space at the center of the turnaround, instead of paving the entire turnaround. Plowing snow and drainage should be a consideration in the design, along with having enough width for large vehicles to negotiate the turnaround. The tee turnaround illustrated in figure 6 in section 98-85 is a permissible permanent design, if posted for no parking.
(6) 
Street intersections with more than four legs are prohibited.
(7) 
Minimum centerline offset distances of adjacent intersections shall be as follows, unless, in the opinion of the City engineer, a shorter distance is unavoidable due to local conditions:
Residential to residential
250 feet
Residential to collector
300 feet
Residential to arterial
500 feet
Collector to collector
300 feet
Collector to arterial
500 feet
(8) 
See section 98-155 for sight distance standards.
[Ord. No. 39-1998, § 3.2.2, 12-1-1998]
The vertical alignment of streets proposed in all subdivisions shall conform to the following standards:
(1) 
The maximum grade for the centerline profile of all streets shall not exceed 8%, except that, in residential subdivisions, where topographic constraints exist, the maximum grade for the centerline profile may be increased to 10% for no more than 200 feet, or 20% of total length, whichever is less. For rural and urban lane sections where there is no heavy truck volume, the maximum centerline profile grade shall not exceed 10%.
(2) 
The minimum desired tangent grade of the street centerline shall not be less than 1%. Grades between 0.5% and 1% will allowed only if strict construction control is adhered to, and as approved to by the City engineer. As a minimum, strict construction control involves the setting of grade stakes, utilizing a competent grade foreman, and final field work approved by the City engineer.
(3) 
Street grades at an intersection shall not be more than plus or minus 3% for a distance of not less than 75 feet from the center of the intersection on each intersecting street.
(4) 
Cross slopes for sidewalks shall be three-eighths inch per foot. Cross slopes for streets shall be one-fourth inch per foot.
(5) 
The minimum length of vertical curves shall be based upon the stopping sight distance, and in no case may be less than 100 feet. The stopping sight distance is based upon the posted speed limits as determined in the latest AASHTO publication titled "A Policy on Geometric Design of Highways and Streets." The method of physically calculating the stopping sight distance is found in that reference, or the ITE Handbook.
(6) 
All changes in grade (intersecting tangents) along a roadway shall be connected by vertical curves, with the length determined by appropriate engineering methods. (Reference: ITE Handbook, Transportation and Traffic Engineering.) The following minimum stopping sight distances are required:
Design Speed
(mph)
Stopping Sight Distance
(feet)
20
125
25
150
30
200
35
250
Stopping sight distance shall be calculated with a height of eye at 3.5 feet and a height of object of 0.5 foot. (Reference: Transportation and Traffic Engineering Handbook, Institute of Transportation Engineers, latest edition.)
[Ord. No. 39-1998, §§ 3.2.4, 3.2.4.2, 12-1-1998]
(a) 
Street and lane summary. The following table provides a summary of the design requirements for streets and lanes. This table, and the street and line drawings in this section, replace appendices D and G found in the subdivision ordinance. The table is to be used with the appropriate figure.
Description
Urban Lane
Rural Lane
Residential Street
Collector Street
Industrial/ Commercial Street
Reference drawing
Figure 1
Figure 1A
Figure 2
Figure 3
Figure 4
Minimum right-of-way (feet)
40
50
50
60
60
Minimum pavement (feet)
24
20
30
34
32
Minimum shoulders (2)
Included
3 feet
Included
Included
Included
Sidewalkd
Yes
No/Yes
Yes
Yes
No/Yes
Minimum grade
0.5%
0.5%
0.5%
0.5%
0.5%
Maximum grade
10%
10%
8%
6%
6%
Minimum centerline radius (feet)
75
75
110
175
250
Minimum tangent between curvesa
Variable
Variable
Variable
Variable
Variable
Roadway crown
2%
2%
2%
2%
2%
Street intersection angle (minimum)
75°
75°
75°
90°
90°
Grade within 75 feet of main road
-3% to +3%
-3% to +3%
-3% to +3%
-3% to +3%
-3% to +3%
Minimum curb radius at intersection (feet)
15
15
15
20
20
Minimum right-of-way radius (feet)
20
20
20
20
30
Curbed section
Yes
No
Yes
Yes
Yes
Parking status
See figure 1
See figure 1A
Both sides
Both sides
None
a
See section 98-83(2). A standard of good engineering practice is required where no specification exists.
b
Curbed section with no parking permitted consists of two ten-foot traffic lanes, plus three feet either side of lanes, for a total of 26 feet of pavement. Using a rural section (non-curbed) with no parking requires a three-foot gravel shoulder with two ten-foot paved traffic lanes (with parking use six-foot gravel shoulders).
c
For aesthetic effect, increasing vegetated area, and for phosphorous reduction, it is permitted to place two inches of loam on the gravel base in the shoulder area for the purpose of maintaining a mowed grass area.
d
See section 98-90 for sidewalk specifics.
e
An urban lane section (featuring curbs and closed drainage) can be used in the rural zones, and a rural lane section (featuring gravel shoulders and open ditches) can be used in the urban zones. The names of such are taken from the predominant usage for that zone.
(b) 
Drainage system requirements. Closed drainage systems are required for all curbed streets. Ditches may be allowed where the lot layout provides an average lot frontage of at least 200 feet. If the portion of the lot abutting the ditch is to be lawn, a 3:1 minimum backslope will be required.
(c) 
Figures. Street design figures referred to in this chapter are as follows:[1]
[1]
Editor's Note: The Street Design Figures are included as attachments to this chapter.
[Ord. No. 39-1998, § 3.2.6, 12-1-1998]
(a) 
Horizontal controls.
(1) 
Monumentation of streets along the right-of-way shall include the following points:
a. 
Points of curvature (PC's).
b. 
Points of tangency (PT's).
c. 
Points of compound curvature (PCC's).
(2) 
A minimum of two intervisible right-of-way monuments shall be tied into the Maine State Plane Coordinate System. This survey connection shall be required when the monuments are within 1/2 mile of a triangulation or traverse station established in conformity with the standards prescribed in 33 M.R.S.A. § 805.
(3) 
The code enforcement officer/planner will maintain an updated list of control stations located within the City.
(b) 
Vertical controls.
(1) 
All established elevations must be based on NGVD mean sea level datum and referenced from a specific benchmark.
(2) 
A minimum of two right-of-way monuments within each development shall be a benchmark monument with an established elevation.
(3) 
Maximum distance between benchmarks shall be 800 inches horizontally, and 50 inches vertically.
(c) 
Surveying standards. Survey control determination shall be to third order national control standards and specifications, as outlined in publications prepared by the Federal Geodetic Control Committee, NOS, NOAA, by a registered land surveyor licensed to practice in the state. Boundary surveys shall be in accordance with state board of registration for land surveyors standards, category 1, condition 2 (or better), with no exceptions.
[Ord. No. 39-1998, § 3.2.7, 12-1-1998]
(a) 
Stormwater runoff collection from streets and sidewalks shall be handled in accordance with the standards of article VI of this chapter.
(b) 
Storm drainage systems must be designed in accordance with standards for a ten-year storm for a rural or residential street and a twenty-five-year storm for a collector, commercial/industrial, or arterial street.
[Ord. No. 39-1998, § 3.2.8, 12-1-1998]
All public portions of the development shall be handicap accessible in accordance with current federal, state or City laws or regulations.
[Ord. No. 39-1998, § 3.2.9, 12-1-1998]
(a) 
Unless other pedestrian accommodations are made, all residential subdivisions shall provide for a sidewalk on at least one side of the street, with the width of the sidewalk to be a minimum of 48 inches.
(b) 
Sidewalks may be provided, but shall not be required, where lot frontages in a residential subdivision are an average of 300 feet or where lot sizes average more than two acres.
(c) 
Municipal sidewalks shall be provided a clear passage width of 60 inches.
[Ord. No. 39-1998, § 3.2.10, 12-1-1998]
There shall be an esplanade located between the curb and sidewalk on residential and collector streets in accordance with the design standards found in section 98-85. Esplanades shall be planted with trees, bushes, shrubbery or grass.
[Ord. No. 39-1998, § 3.2.11, 12-1-1998]
(a) 
Guardrails shall be used in any locations where street embankments exceed three to one, or 33% (downslopes only). Street intersections which form a "T" shall have a reflective guardrail opposite the street which terminates at the intersection. MDOT specifications shall be used.
(b) 
The face of any guardrail shall be aligned so as not to reduce the width requirement of any section feature, such as shoulder width, sidewalk width, etc. This will require an additional width (usually two feet) to allow for the guardrail. A guardrail can be any suitable device designed for the purpose that meets AASHTO or MDOT standards. Other systems such as ornamental stones must be approved by the planning board, based on review by the City engineer.