All newly constructed roads shall be provided with a defined street edge. The provision of defined street edges shall help delineate areas that are appropriate for vehicular traffic, increase the aesthetic appeal of public spaces within the town, and help manage and control storm water runoff from areas of impervious surface. Different types of streets shall dictate the appropriate manner in which to define the street's edge.
(A) Standard curb and gutter.
(1) Curb and gutter systems shall be constructed according to the State Department of Transportation's Division of Highways' standards. The following shall be typical cross sections of standard curb and gutter systems and valley gutter systems:
(2) The standard curb and gutter system or the valley gutter system shall be used to convey storm water runoff. Typically this type of storm water runoff control is used to collect and convey the runoff to a centralized (end of pipe) treatment facility. If a treatment facility is not required and is not installed, then the runoff shall be released from the conveyance mechanism in a non-erosive manner. The standard or valley system shall also serve the purpose of effectively defining the street's edge and separating, both horizontally and vertically, the vehicular traffic from any pedestrian activity.
(B) Standard or valley curb and gutter systems and bio-retention facilities.
(1) More development is incorporating storm water management techniques within the site design of a project. This is typically known as an aspect of low impact development. Not to be construed as an exhaustive list, bio-retention cells, grassed swales, rain gardens and storm water wet lands are all facilities that are designed to treat storm water on site with little or no concrete or metal conveyance (micromanagement). These techniques are typically viewed as positive due to the fact that the systems mitigate large quantities of water flowing at high velocities, they generally can treat the runoff for pollutants, and typically aid in groundwater recharge. To facilitate the use of these systems, standard curb and gutters or valley gutters may be used by incorporating curb cuts. In this fashion the road's edge is defined and storm water is effectively conveyed, but for short distances to infiltration aiding systems. While this street edge technique does provide vertical separation of vehicular traffic from pedestrian activity, the larger separation comes from the implementation of the storm water control system.
(2) Inlets to the storm water control system shall be provided with energy dissipaters in order to prevent erosion from entering waters. Inlets shall also be spaced at least every 12 feet on center and shall be a minimum of 12 inches wide. Other than these curb cuts, the curb and gutter system shall be designed and constructed according to division (A) above. This division (B) shall not be construed to offer a comprehensive guide on the construction of the storm water systems, rather the curb adjacent to the system.
(C) Flat curb.
(1) This method of street edge definition includes the curb, but not the gutter. Typically, this type of curb is used in conjunction with the micromanagement storm water systems discussed in division (B) above as it facilitates sheet flow into the management system. However, flat curb systems may be utilized in other applications, such as alleyways, as well as other appropriate applications. The flat curb system defines the street's edge, offers minor traffic calming capabilities, allows storm water to enter retention facilities as sheet flow, and can offer minor separation of pedestrians from vehicles. The following is an example of a flat curb system:
(2) It is highly recommended that the flat curbs be constructed of permeable materials, such as permeable pavers, permeable concrete, or permeable asphalt. These flat curb areas will not be heavily used and so these types of permeable materials will remain structurally sound for a considerable time.
(D) Streets with on-street parking.
(1) For streets that are provided with on-street parking, an edge defining mechanism shall be installed on the moving vehicular traffic side of the parking spaces. The edge defining mechanism shall be a flat curb, a wide painted stripe or some other effective means. The following diagram shall illustrate the placement of the edge definition:
(2) In most cases a similar curb or edging system will be provided on the opposite side of the parking space as well, but for the purposes of this division (D), the edge definition along the street side of the parking places shall be required.
(E) Streets with bike lanes.
(1) When a street is constructed and the street incorporates the provision of a bicycle lane, then the bicycle lane may serve as the street edge defining mechanism. The street edge may be comprised of the typical white line that delineates the bicycle lane, a different colored material as the bicycle lane, or a combination of both. For the purposes of this division (E) the street edge shall be deemed defined by the bicycle lane; however, another edge defining mechanism may be used on the non-vehicular side of the bicycle lane. The following is an example of a street whose edge is defined by a bicycle lane:
(2) While it is desirable to incorporate permeable, porous and/or recycled materials into traditionally impervious surfaces, the material chosen to construct a bicycle lane should be done in a manner that weighs the texture of the surface (as it relates to a bicyclist's riding experience) against the desired environmental benefit of the material.
(F) Other edge defining techniques. It is recognized that other methods of supplying an adequate road edge exist and may be more appropriate for a given project than those listed above. As such, proposed alternative approaches shall be considered on a case by case basis.
(G) Preliminary meeting. If a proposed development project is governed by this section, then a clear description and/or depiction of the proposed street edge defining method shall accompany the applicant's first application for development approval. Upon review of the application, the town Zoning Administrator or Subdivision Administrator shall forward the application to the Town Manager and Public Works Director for comments specifically relating to the proposed method of street edge definition. The approved street edge defining method shall be a part of the approved development plan and shall be binding as such.
(Ord., Art. XI, § 1113, passed - -)