(A) General. The standards hereinafter set forth are minimum standards as the same are applicable to each road classification as assigned by the Town Planning and Zoning Commission under the town’s subdivision regulations.
(B) Width of right-of-way. Roads shall have the following minimum width of right-of-way according to their classification, and as necessary for anticipated traffic capacity, type of traffic, turning movements and construction requirements: local residential: 50 feet. In the event that the applicant does not own the land adjoining the right-of-way established for a road, said right-of-way shall have such extra width or area as is necessary to accommodate all road construction within the right-of-way without encroachment on the adjoining land. In lieu of extra width or area, the applicant may obtain rights to slope on the adjoining land provided that such rights are in a form approved by the Board of Selectmen.
(C) Width of pavement. Roads shall have the following width of pavement centered between road lines. When curbs are required, the width is that area lying between the faces of the two curbs.
(1) Local residential. Twenty-two feet minimum. (Roads within subdivisions ate subject to the planning and zoning subdivision regulations.)
(2) Turnarounds. Fifty-foot radius. Fifty-two-foot radius when curbed.
(D) Grade. The minimum grade for any street shall be 1%. The maximum grade shall not exceed the following:
(1) Local residential: 10%;
(2) Turnarounds: 5%; and
(3) Arterial and collector streets: 8%.
(E) Vertical curves. Vertical curves shall provide a minimum stopping sight distance of 200 feet on local residential streets. The design speed shall be subject to the approval of the Board of Selectmen.
(F) Intersections. The following standards shall apply to street intersections.
(1) Spacing. No more than two roads shall intersect at one point. Centerlines of intersections shall be spaced not less than 500 feet apart, except when conditions justify a variance.
(2) Angle of intersection. Roads shall intersect one another at or as near to a right angle as is practical. No intersection shall be at an angle of less than 60 degrees and not more than 120 degrees for a distance of at least 100 feet from the line of intersection.
(3) Corner lots. At a street intersection, property line corners shall be rounded by an arc having a minimum radius of 32 feet or more if required by roadway radii.
(4) Approach grades. The approach grades at intersections shall be no more than 2% for side roads for 100 feet. Side roads at intersectional sight distances of at least 300 feet for local roads. The driver’s eye shall be assumed to be 20 feet behind curb line and sight distance shall be in accordance with the Geometric Design Guide for Local Roads and Streets, published by the American Association of State Highway Officials.
(G) Horizontal alignment. Connecting curves between tangents shall be provided for all deflection angles in excess of five degrees. Suitable tangents shall be provided between curves with a minimum tangent distance of 150 feet between reverse curves:
(1) Local residential. One hundred fifty feet (minimum radius as measured along the roadway centerline); and
(2) Arterial and collector streets. Three hundred fifty feet (minimum radius as measured along the roadway centerline).
(H) Construction. Roads shall be constructed in accordance with the following standards.
(1) Survey. A centerline survey of the road shall be run in the field and suitable construction ties established to all control points. Stations shall be established at 50-foot intervals and all points of curvature and points of tangency. A construction stake shall be placed perpendicular, or radial in the case of curves, at each station on both sides of the road, and clear of all construction. The construction stake shall be marked with the station, offset to centerline and cut or fill to profile grade as measured from the top of the stake. A stake sheet showing the stations, profile grade, stake offsets, and glades and cuts and fills shall be prepared and presented to the Board of Selectmen before construction begins. Permanent benchmarks shall be established and recorded with the Board of Selectmen throughout the length of the project at 500-foot intervals or as directed by the Board. The datum for benchmarks shall be town, state or U.S. datum; an assumed datum may be used only with the written permission of the Board of Selectmen. Changes in horizontal or vertical alignment of the road from the approved plans shall not be made except with written permission of the Board of Selectmen. Grade stakes shall be protected and preserved until the construction work is approved by the Board of Selectmen.
(2) Clearing. The entire area of the right-of-way required to be graded in accordance with the standard cross-section shall be cleared of trees, stumps, brush, roots, large rocks, ledge and other unsuitable materials, except that trees suitable for street trees shall be left standing as directed by the Board of Selectmen or the Planning and Zoning Commission, in the case of a subdivision.
(3) Subgrade. For the full width of the required pavement, plus two feet where curbs are used, all loam, organic material, soft clay, spongy material, boulders, ledge and other unsuitable material shall be removed and replaced by materials approved by the Board of Selectmen. All fill that is placed to an elevation of less than three feet above the water table at the time of filling shall consist of stone, gravel or other free-draining soil approved by the Board of Selectmen. Where ledge rock is encountered, it shall be removed to a depth of one foot below subgrade and the area backfilled with crushed stone or gravel. Embankments shall be constructed of crushed stone, gravel or the suitable material deposited in successive layers, for the full width of the embankment The subgrade shall be rolled with a minimum ten-ton roller or equivalent before placing the base course. All underground drainage and utilities shall be installed prior to completion of the subgrade for receiving the base course.
(4) Base course. A base course not less than 16 inches (the bottom 12 inches to meet Grade A standards and the top four inches to meet Grade C standards of State DOT Form 814) in depth and for the full width of pavement plus two feet where the curbs are used shall be constructed of processed stone or processed gravel in accordance with Form 814. The base course shall be rolled with a minimum ten-ton roller and shaped with a cross slope of one-quarter inch per foot from the centerline. (Standard Proctor tests shall be run on the base course in accordance with accepted engineering practice unless such tests are waived by the Board of Selectmen.) Any areas of the base course, which have become impervious due to concentration of fine materials shall be scarified and recompacted.
(5) Surface course. The paved surface shall have a cross slope of one-quarter inch per foot from the centerline and shall be constructed of two courses of bituminous concrete, each one and one-half inches in depth after compaction to the full required width plus two feet where curbs are used. An emulsion tack coat is required when three successive days pass between the laying of the base course and successive courses. Construction methods shall conform to Form 814. Materials shall conform to Form 814, Bituminous Concrete Paving Mixtures Binder Course Grading II. The course shall be Class I Bituminous Concrete.
(6) Curbs. Granite, concrete or bituminous concrete lip curbs, or combinations thereof shall be provided in areas deemed appropriate by the Board of Selectmen or, in the case of subdivisions, by the Planning and Zoning Commission. Such curbs shall be located on the outer edge of the completed pavement All curbing shall have a cross section approved by the Board of Selectmen. Granite curbing will have a base of six inches and a height of 20 inches. The curbing will be set on edge with six inches of exposed face (smooth) above the finish pavement course. Concrete curbing shall have a base of eight inches and a total height of 20 inches of which six inches shall be located above the finished surface course of the street. Bituminous lip curbing will be laid on top of the binder course, an emulsion tack coat will be used prior to setting curbing. Place curbing as shown on typical roadway section. All work and materials for the different types of curbing shall conform to Form 814.
(7) Slopes. All earth surfaces of slopes, and areas that have been disturbed in any way due to grading and construction of the roads, shall be covered with a minimum of four inches of top soil and suitably seeded or planted and mulched to prevent soil erosion. The Board of Selectmen may require the removal or lowering of embankments adjacent to street intersections in order to assure adequate sight distance at the intersection. No cut or fill sections beyond the right-of-way shall extend into property outside the subdivision or property not owned by the applicant, unless appropriate slope rights/appropriate retaining walls shall be constructed within, the subdivision to prevent encroachment upon adjoining property, provided these do not obstruct sight lines.
(8) Underdrains. The Board of Selectmen may require the installation of suitable under drains beneath the street pavement or in the right-of-way where necessary to protect the stability of the pavement.
(9) Guide rails. Suitable guide railing shall be installed along all roads where there will be a “fill” embankment with a depth of four feet or more within 20 feet of the edge of the pavement, except that, upon written approval of the Board of Selectmen, guide rails will not be required where embankment slopes are no steeper than six to one.
(10) Sidewalk ramps. Sidewalk ramps shall be constructed on all new streets at crosswalks, or on existing streets at crosswalks when either the curb or sidewalk is reconstructed or repaired.
(I) Cross-section. Local residential roads shall be designed with a cross-section in accordance with the cross-section details that are a part of these specifications and as stated above.
(J) Soils report. When deemed necessary by the Board of Selectmen, a soils report shall be prepared for any roadway construction by a competent licensed professional engineer. The content of such report and the qualifications of the preparer shall be subject to the Board of Selectmen, or its authorizing agent’s, review and approval.
(Ord. passed 1-11-1984; Ord. passed 9-18-2002)