These standards are intended to create a connected transportation system between neighborhoods and commercial areas within the county.
(A) Purpose. The specific purposes of this section include:
(1) Promoting walkability through additional connections and shorter block lengths;
(2) Improving emergency response time;
(3) Increasing effectiveness of delivery access;
(4) Providing better routes to schools and parks;
(5) Reducing impacts of development on master-planned arterial and collector roads by providing alternative routes; and
(6) Preventing isolated developments that increase dependency on automobiles.
(B) Provisions. To meet the intent of this section, the following provisions shall be applied to all new nonresidential developments within the Town Center Zone.
(1) Definitions. For the purpose of this section, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
BLOCK LENGTH. The distance along any given road frontage between two intersections with three or more connecting links (see Figure 155.269-1 below). Links that connect into a cul-de-sac shall not be considered the termination point of a BLOCK LENGTH.
Figure 155.269-1 |
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CHICANE. An extension of a curb typically on a local street to provide an element of traffic calming.
CONNECTIVITY INDEX. A ratio of roadway links and nodes that serves as a metric for measuring the level of connectivity.
CUL-DE-SAC LENGTH. The distance from the street intersection to the throat of the cul-de-sac bulb (see Figure 155.269-2 below).
Figure 155.269-2 |
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CURB EXTENSION. An extension of a curb in a roadway to narrow the road at pedestrian crossings to provide additional safety for pedestrians and serves as a traffic calming measure.
LINKS. Streets that connect to nodes or external streets not included in the proposed development.
NODE. Street intersection or cul-de-sac located within a proposed development. A street intersection exists where two or more named roads intersect.
(2) Circulation plan. A circulation plan shall be provided as part of a preliminary subdivision plat application.
(a) The circulation plan must address street connectivity, pedestrian circulation, emergency access and parking movements. In cases where cut-through traffic is likely, traffic calming measures such as curb extensions, chicanes, raised crossings or other features may be required.
(b) The circulation plan shall show the connectivity index, block length dimensions, cul-de-sac length dimensions, pedestrian facilities and any proposed traffic calming features.
(c) The circulation plan must take into account access and connectivity on adjacent parcels. On a case-by-case basis the Planning Director and County Engineer may require changes to stub road locations if it will increase the connectivity within an adjacent property.
(d) A circulation plan will be required for proposed developments with more than one acre in project size or with more than ten units. The Planning Director and County Engineer may waive the requirement for a circulation plan on a case-by-case basis.
(3) Connectivity index calculation. The required connectivity index is calculated by dividing the total number of links by the total number of nodes (see Figure 155.269-3 below).
Figure 155.269-3 |
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(a) For the purposes of calculating the number of total links, one link beyond each node shall be included in the connectivity index calculation.
(b) Street stubs that provide future access to adjacent properties or streets that connect to existing streets are considered links.
(c) An additional one-half link shall be included in the connectivity index calculation for each of the following:
1. Hard surface pedestrian connection through a cul-de-sac with a minimum width of ten feet including an additional two-foot soft shoulder on each side (see Figure 155.269-4 below);
Figure 155.269-4 |
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2. Hard surface master-planned trail connection with a minimum width of ten feet including an additional two-foot soft shoulder on each side (see Figure 155.269-5 below);
Figure 155.269-5 |
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3. Internal hard surface trail segment connecting two roads with a minimum width of ten feet including an additional two-foot soft shoulder on each side (see Figure 155.269-6 below).
Figure 155.269-6 |
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(c) An additional one-fourth link shall be included in the connectivity index calculation for each roadway segment where homes face an amenitized open space, park or natural area (see Figure 155.269-7 below). The roadway segment shall have a minimum 300 feet of frontage along the said open space.
Figure 155.269-7 |
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(4) Residential connectivity standards. All new residential subdivisions with ten or more units or more than one acre shall meet the following connectivity index, block length and cul-de-sac length standards for public roads. Private roads shall be reviewed on a case-by-case basis; however, a public road may be required to prevent a private road in a subdivision from stubbing into a future or existing public road.
(a) Required connectivity index. The minimum required connectivity index shall be required based on the project density as identified in the following table of minimum connectivity index scores:
Density | Minimum Index Score |
0 - 2.5 DU/AC | 1.5 |
2.6 - 4 DU/AC | 1.6 |
4.1+ DU/AC | 1.75 |
1. Reduction in required connectivity index: The required connectivity index may be reduced if the applicant provides clear and convincing evidence that it is impossible or impracticable to achieve due to the following limitations:
a. Topography;
b. Natural features including lakes, rivers and designated wetlands;
c. Existing adjacent development;
d. Rail corridors; and
e. Limited access roadways.
2. Reductions in the required connectivity index will be reviewed on a case-by-case basis and must require recommendations from the reviewing departments and Planning Commission and approval by the County Commission.
3. The total allowed reduction to the required connectivity index will be based on an analysis of existing conditions that prevent connections. As part of the analysis, county staff will ensure the internal connectivity of the subdivision meets the required connectivity index and that connectivity is provided to adjacent properties where possible.
(b) Maximum block lengths.
1. Maximum block lengths allowed shall be required based on the project density as identified on the following table:
Density | Maximum Block Length |
0 - 2.5 DU/AC | 1,000 feet |
2.6 - 4 DU/AC | 800 feet |
4.1+ DU/AC | 600 feet |
2. Increase in block length: The maximum allowed block length may be increased if the applicant provides clear and convincing evidence that it is impossible or impracticable to achieve due to the following limitations:
a. Topography;
b. Natural features including lakes, rivers and designated wetlands;
c. Existing adjacent development;
d. Rail corridors; and
e. Limited access roadways: Increases in block length will be reviewed on a case-by-case basis and must require recommendations from the reviewing departments and Planning Commission and approval by the County Commission.
(c) Cul-de-sac length standards.
1. Maximum cul-de-sac lengths allowed shall be required based on the project density as identified on the following table:
Density | Maximum Cul-de-sac Length |
0 - 2.5 DU/AC | 400 feet |
2.6+ DU/AC | 250 feet |
2. Cul-de-sacs shall not be allowed in the RM-15 or RM-7 Zones unless the applicant provides clear and convincing evidence that a cul-de-sac is necessary to develop the entire parcel due to the following limitations:
a. Topography;
b. Natural features including lakes, rivers and designated wetlands;
c. Existing adjacent development;
d. Rail corridors; and
e. Limited access roadways: Requests for cul-de-sac within the RM-15 or RM-7 Zones will be reviewed on a case-by-case basis and must require recommendations from the reviewing departments and Planning Commission and approval by the County Commission.
(5) External street connectivity standards. In addition to the internal street connectivity standards, external connectivity shall be maintained.
(a) Cul-de-sacs. In cases where cul-de-sacs have one or two rows of lots between the end of the cul-de-sac and an external road, a hard surface pedestrian connection with a minimum width of ten feet including an additional two-foot soft shoulder on each side shall be utilized to connect to the external street (see Figure 155.269-8 below).
Figure 155.269-8 |
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(b) Pedestrian connections. Pedestrian connections shall be utilized to connect proposed developments to master-planned trails and adjacent existing or future developments where applicable. Connections shall be of a hard surface with a minimum width of ten feet including an additional two-foot soft shoulder on each side.
(6) Nonresidential connectivity standards. All new nonresidential subdivisions containing the dedication of public roads shall meet the following connectivity index and block length standards. Private roads shall be reviewed on a case-by-case basis; however, a public road may be required to prevent a private road in a subdivision from stubbing into a future or existing public road.
(a) Required connectivity index.
1. The minimum required connectivity index score shall be one and one-half for nonresidential developments.
2. Reduction in required connectivity index: The required connectivity index may be reduced if the applicant provides clear and convincing evidence that it is impossible or impracticable to achieve due to the following limitations:
a. Topography;
b. Natural features including lakes, rivers and designated wetlands;
c. Existing adjacent development;
d. Rail corridors; and
e. Limited access roadways: Reductions in the required connectivity index will be reviewed on a case-by-case basis and must require recommendations from the reviewing departments and Planning Commission and approval by the County Commission. The total allowed reduction to the required connectivity index will be based on an analysis of existing conditions that prevent connections. As part of the analysis, county staff will ensure the internal connectivity of the subdivision meets the required connectivity index and that connectivity is provided to adjacent properties where possible.
(b) Maximum block lengths. Maximum block lengths allowed shall be 500 feet for nonresidential subdivisions.
1. Increase in block length: The maximum allowed block length may be increased if the applicant provides clear and convincing evidence that it is impossible or impracticable to achieve due to the following limitations:
a. Topography;
b. Natural features including lakes, rivers and designated wetlands;
c. Existing adjacent development;
d. Rail corridors; and
e. Limited access roadways: Increases in block length will be reviewed on a case-by-case basis and must require recommendations from the reviewing departments and Planning Commission and approval by the County Commission.
2. Cul-de-sac standards: Cul-de-sacs shall not be allowed in any nonresidential zone unless the applicant provides clear and convincing evidence that a cul-de-sac is necessary to develop the entire parcel due to the following limitations:
a. Topography;
b. Natural features including lakes, rivers and designated wetlands;
c. Existing adjacent development;
d. Rail corridors; and
e. Limited access roadways: Requests for cul-de-sacs within nonresidential zones will be reviewed on a case-by-case basis and must require recommendations from the reviewing departments and Planning Commission and approval by the County Commission.
3. Cross-access: It is highly encouraged for nonresidential site plans to provide cross-access to adjacent developments to allow auto and pedestrian trips to occur between developments without the need of using the street (see Figure 155.269-9 below).
Figure 155.269-9 |
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(Prior Code, § 8-5K-5) (Ord. 18-06, passed 8-7-2018)