35-6-14 Street connectivity requirements

Connectivity standards require that the streets in new neighborhoods have a minimum level of connectivity both within the neighborhood and outside it to existing and future developments. Street connectivity provides various benefits, including access to community destinations, active transportation, emergency response, and traffic performance. While traffic impact must be reviewed for connections to new subdivisions, connectivity is generally better for community traffic performance and safety. (1) Internal connections: (a) Minimum connectivity index: The connectivity index measures how connected the streets in an area are. The connectivity index is the ratio of the street segments in a given area to the intersections in the same area. The connectivity index is the number of “links,” or street segments, divided by the number of “nodes,” which include intersections and dead ends within a given area. For the purposes of the code, the area is the subdivision being proposed, including any major streets along its edges. The connectivity index shall be at least as high as the minimums specified in Table 23 in the Active Transportation Implementation Plan. The example connectivity plans in Figures 2-5 and 2-6 of the Active Transportation Implementation Plan include the identification of links and nodes and connectivity index calculations. (i) Maximum block length 1. Maximum block lengths ensure that street networks have a minimum level of intersection density. Block lengths in the subdivision shall not exceed the maximums in Table 2-3 in the Active Transportation Implementation Plan. Subdivisions zoned RR-1, RR-5, and RR-10 have no block length maximums. 2. To maintain flexibility in subdivision design, for every 40 lots included in the development, one exception to the maximum block length is allowed. A block may be up to 2.5 times as long as the minimum. 3. In addition, access management requirements for UDOT-managed streets may also allow block lengths along these streets to be longer. Active transportation pathways may be substituted in this case to maintain transportation connectivity. 4. The example connectivity plans in Figures 2-5 and 2-6 of the Active Transportation Implementation Plan include identifying maximum block lengths and exceptions. Connectivity Requirements Internal Connectivity External Connectivity Zone Connectivity index (links per node) Maximum block length (ft)1 Cul-de-sac maximum length (ft)2 Maximum spacing of connection to collector and arterial level streets3 Maximum stub street spacing R-M-30 1.5 R-M-15 1.5 R-M-7 1.5 R-1-8 1.5 R-1-10 1.5 R-1-12 1.5 R-1-21 1.5 1,320 N/A RR-1 1.5 N/A 1,320 N/A RR-5 1.5 N/A N/A N/A RR-10 1.5 N/A N/A N/A 1 There can be one exception to the maximum block length per 40 lots, where one block face can be up to double length. 2 Every cul-de-sac must have a pedestrian connection to the other side of the block. 3 Excludes connections to UDOT-managed streets. (ii) Maximum cul-de-sac length 1. Cul-de-sacs and other dead-end streets included in a subdivision shall not be longer than the limits in Table 2-3 in the Active Transportation Implementation Plan. 2. Stub streets intended for future connections are not included in this requirement. (iii) Active transportation connection for each cul-de-sac 1. A shared-use path meeting the design standards in Section 2-4 of the Active Transportation Implementation Plan for off-street paths must be included at each internal cul-de-sac or dead-end street. (iv) External connections 1. Stub Streets: Stub streets are streets that dead-end against vacant or undeveloped land with the intention of connecting to development on that land in the future. To maintain a consistent street network that ties together different subdivisions, stub streets shall be built at a minimum spacing that matches the maximum block length requirements in Table 2-3 of the Active Transportation Implementation Plan. Stub streets shall not include temporary cul-de-sacs and shall be no longer than 150 feet. For zones with no maximum block spacing, stub streets shall be built as extensions of the subdivision’s street network. 2. Master Planned Trails: Active transportation connections in the subdivision shall connect the subdivision to any master-planned trails where applicable. These connections can be any of the Shared Use Path types specified in Section 2.4 of the Active Transportation Implementation Plan. (v) Connectivity Plan 1. Achievement of connectivity standards must be shown on a Connectivity Plan to be submitted with each development application and including the following information. Basic information: (A) Street links (B) Nodes (C) Block length dimensions (D) Cul-de-sac length dimensions (E) Connectivity index (F) Maximum block lengths (G) Stub streets with the minimum spacing (H) Active transportation – only links connecting cul-de-sacs or to accessmanagement controlled streets. 2. For examples of Connectivity Plans, see Figures 2-5 and 2-6 in the Active Transportation Implementation Plan. (vi) Exceptions 1. The connectivity requirements 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: Natural features including lakes, rivers, and designated wetlands (B) Existing adjacent development: A new subdivision must connect to an adjacent pre-existing development and the connection must be balanced with the external connectivity requirements (for example, if the pre-existing development has stub streets, they must be incorporated into the new subdivision to best adhere to the connectivity requirements) (C) Rail corridors (D) Limited access roadways 2. Reductions in the required connectivity index will be reviewed on a case-by-case basis and must require approval by the Planning Commission or the Community Development Department. (Ord. 2022-32, 11/29/22)