Sustainable Land Development Today - January 2009 - (Page 42)

SLDT INNOVATION Going with the Flow Traditional – and many new – neighborhood designs do not deliver lasting value for the community due to ineffective traffic flow. By Rick Harrison Part 2 of a 2 Part Series: In part one of this series, we explored the benefits of providing superior traffic flow and examples for delivering it. In part two, we look at additional cases where improved flow could have provided lasting value, and some developments that flow well. omparing improved traffic-flow design techniques, which we refer to as “flow,” with those that have been implemented in newer Traditional Neighborhood Design (TND) developments reveal the opportunities to save both time and energy through efficient routing. For the most part, TND planning incorporates a pure grid plan with main arterial streets at every section line (onemile intervals) typical of an inner-core, suburban development that allows residents to get home with few turns. Since the number of trips today is considerably greater per family than in previous generations, these older grid designs have given way to limited-access, arterial roads. Looking at how flow can be applied to TND, we will see what can happen when developments depart from the grid approach. Liberty on the Lake (Graphic 1), the first, New Urban-style development in the Minneapolis, Minnesota area, set new benchmarks for architecture and landscape detail. However, from a flow standpoint, it can be improved. The main C Graphic 1: Liberty on the Lake, Minneapolis, Minnesota 42 January 2009 Sustainable Land Development Today entrance shown on the upper left part of livability and flow. The simple reality is the picture has a traffic circle; however, that the real environmental solution to there is not enough traffic to warrant a carbon emissions due to traffic is circle. It causes drivers to slow down, “greener” automobiles, not the eliminalook, turn, slow down again, and accel- tion of automobiles. erate, while continuing on the same main street to get home – which typically encounters many intersections and individual legs. Likewise, Cobblestone in Apple Valley, Minnesota (Graphic 2) is a literal maze of short street segments creating restrictions to flow, which eats up time and energy. Further, the increased amount of paved surfaces adds costs to the project and magnifies stormwater runoff Graphic 2: Cobblestone, Apple Valley, Minnesota issues because of the increased amount of impervious surface. Neighborhoods exist for almost a cenOne of the precepts of the New Ur- tury after they are designed and develbanism is supposed to be connectivity, oped. On the other hand, technology and but we also need to be mindful that the innovation will continue to impact autopatterns need to be efficient – a critical mobile designs and significant changes element in today’s (and tomorrows) en- are finally on their way. Therefore, as ergy crunch. New Urbanists’ attempt to neighborhood designers, the most suscure this by reducing the need for tainable solution for society is to optivehicles. They contend that a mize traffic flow to maximize energy TND will result in less reliance on conservation. Let the car manufacturers vehicles, thereby solving the prob- work on making cars more efficient. lems related to consumption and exposure. The reality is that our Conventional Suburbia society is, and will continue to be, A problem in suburban design is that dependent on vehicles to a degree many contain too many internal collecthat a TND cannot overcome be- tor streets (non-fronted) that have relacause we demand the freedom to tively low traffic load. An arterial street travel on own terms. system, especially in small- to modestUltimately, sustainable devel- sized developments, consume land that opment must be more sophisti- could have been buildable lots. But even cated by considering both

Table of Contents Feed for the Digital Edition of Sustainable Land Development Today - January 2009

Sustainable Land Development Today - January 2009 Contents Our Voice Your Voice The BottomLine SLDI in Focus Calendar Industry Rebound Will Require Balanced Approach What Happened to Fannie and Freddie? Added Value in Entitlements Industry Spotlights Technology Wastewater Innovation Classifieds Advertiser Index Editorial Board SLDT Resources Last Word

Sustainable Land Development Today - January 2009

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