Planning boards can evaluate their current ordinances to determine if they adequately address access management strategies. By comparing current ordinances and regulations to these guidelines, communities can identify areas in the ordinances or regulations where access management strategies can be incorporated.

The following measures are based on the access management guidelines that were developed by the Nashua Regional Planning Commission in 2002.

Model Regulation (Subdivision and Site Plan)

Unless access management regulations are incorporated into a specific zoning or overlay district, most of the techniques are a collection of regulations that work together in a comprehensive scheme to control access to a transportation network. Below is some suggested language that can be incorporated into existing subdivision and site plan review regulations.

Traffic

The planning board shall determine that the proposed development will not cause unreasonable highway or public road congestion or unsafe conditions with respect to the use of the highways or public roads existing or proposed, and the traffic associated with the development shall maintain the existing level of service within 200 feet of any existing or proposed curb-cut. In making its determination, the planning board shall consider factors such as vehicular circulation, parking, pedestrian circulation, and landscaping.

The board shall also consider a statement or report from a traffic engineer indicating that the proposed development will not create or further contribute to unsafe traffic conditions, and consider statements from the fire department, police department and public works department in evaluating the project for highway or public road congestion or safety.

Pedestrian and Bicycle Access and Safety

The planning board shall determine that the proposal is designed to accommodate bicyclists and pedestrians, and addresses issues of bicycle and pedestrian access, safety and circulation both within the site and to points outside of the site. In making its determination, the planning board shall consider factors such as vehicular circulation, parking, pedestrian circulation, and landscaping.

Vehicular Circulation Standards

General Provisions – No person shall cut, break or remove any curb along a street except as herein authorized. No person shall construct, alter or extend any driveway approach that can be used as a parking space or area between the curb and private property. The provisions in this section are based on principals of access management.

Driveway Approach Width (commercial and industrial) – The maximum width of a driveway approach for a two-way driveway shall not exceed 36 feet including two-foot shoulders. The minimum width of a driveway approach for two-way driveway shall not be less than 24 feet including two foot shoulders.

Driveway Approach Width(multifamily residential) – The maximum width of a driveway approach shall not exceed 15 feet. The minimum width of a driveway approach shall not be less than 10 feet.

Driveway Access Spacing – Driveway access spacing shall be measured from the edge of the proposed driveway pavement to the nearest edge of the roadway of the adjacent or opposite driveway or street.

Intersection Alignment – If a proposed driveway cannot meet the requirements of the sections above, then the proposed driveway shall be aligned directly opposite an existing or proposed opposite driveway and the configuration shall be treated as a four-way intersection.

Angle of Driveway Approach – The angle of driveway approach shall be approximately 90 degrees for two-way driveways and between 60 degrees and 90 degrees for one-way driveways.

Turning Radii – The principal users of the roadway shall be considered when determining the inside turning radii. The inside turning radii shall vary between a minimum of 15 feet and a maximum of 30 feet and meet the minimum and maximum requirements of Table 3.3.2.

Corner Clearance – No driveway approach may be located closer to the corner than indicated in Table 3.3.3. The measurement shall be taken from the intersection of property lines at the corner to the nearest edge of the proposed driveway pavement. When these requirements cannot be met due to lack of frontage, the nearest edge of the proposed driveway pavement shall be located as far as possible from the intersection of property lines at the corner.

Driveway Throat Length – Driveway throat length shall be measured from the edge of the property line to the furthest end of the driveway. A minimum driveway throat length of 25 feet for collector streets, 40 feet for minor arterials, and 55 feet for major arterials shall be required. The purpose of the driveway throat length is to allow for traffic entering the site to be stored on site in order to avoid a queue of traffic on the roadway causing delays and a potentially hazardous situation. (See Figure 3.3.4.)

Shared Access – Shared driveways are encouraged and may be required between adjacent lots that front on arterial and collector streets. In such cases, a joint access easement between the property owners may be required. The location and dimensions of said easement shall be determined by the planning board (See Figure 3.3.5).

All-Season Safe-Sight Distance

All-season safe-sight distance is defined as a line that encounters no visual obstruction between two points, each at a height of three feet nine inches above the pavement, and 10 feet back from the road pavement as to represent the critical line of sight between the operator of a vehicle using the access and the operator of a vehicle approaching from either direction. Safe sight distance shall be compatible with the maximum speed limit posted on the roadway as indicated in Table 3.3.4. To prevent hardship to owners of small parcels of land or special land uses, exceptions to the all season safe sight distance requirements should be allowed for individual homes, agricultural land, public works land, highway department land and temporary accesses for vehicles such as construction vehicles, gravel trucks and log trucks. The road shall then be properly signed for “Blind Drive” or “Trucks Entering.”

Source: Access Management Guidelines, Nashua Regional Planning Commission, April 2002