Title
Consider an ordinance amending Chapter 36, Code of Ordinances (2010 Edition), regarding connectivity requirements for new residential subdivisions. (Second Reading)
Body
This is the second code amendment City Council will consider at this meeting regarding the Round Rock Zoning and Development Code.
In response to concerns from residents about traffic flow through and between neighborhoods, staff has created subdivision connectivity requirements. The goal is to require subdivision design to provide multiple ways to get into, out of, and around new residential subdivisions. There are two primary methods for increasing connectivity: requiring more streets to intersect with one another, and requiring more connections to public streets. Other tools include requiring stub streets to vacant properties to encourage connectivity in the future, and placing limits on block lengths.
The first primary method is calculated with a connectivity index (CI), which is a ratio of the number of street segments (links) to intersections and end points (nodes). Transportation and planning literature have determined that a CI of 1.40 or greater is the indication of a well-connected subdivision. The amendment proposes a minimum roadway CI for new residential subdivisions of 1.35, with any subdivision having a CI below 1.40 required to incorporate enough pedestrian links to bring the total CI up to at least 1.40. For reference, a random sampling of 35 existing Round Rock neighborhoods representing a wide geography and age was determined to have a mean CI of 1.36, and of those, the 8 which were platted in the last 5 years had a mean CI of 1.39.
The amendment also proposes new residential subdivisions to have a minimum number of connections to existing public streets, a minimum number of stub streets to adjacent vacant properties, and a block length limit of 1,000 feet. This limit can be exceeded with P&Z approval, but an interrupting feature must be placed near the mid-point of ...
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