Mon 8 Nov 2010
The draft LEED 2012 rating systems were released for public comment today. The proposals contain new and revised credits that relate to the location, transportation options, and urban design of projects. Here I’ll review the changes that are of greatest interest to new urbanism and smart growth advocates.
The following proposals are in the Building Design & Construction document, which includes most of the LEED rating systems. “LT” stands for Location and Transportation, which is a new category within LEED systems.
Please note that “LEED 2012″ is my own personal shorthand for these draft proposals. The more accurate and official term is “proposed update to LEED” with no year associated.
LT Prerequisite: Bicycle Storage
LEED has been critiqued for a variety of flaws both real and alleged. But one thing you can always count on is a mention of the bike rack credit. Every critic or reporter has a sworn duty to point out that bike racks can earn a LEED credit point. Installing bike racks is cheap and easy compared to (for instance) making buildings more energy efficient, and may be worth the same number of credit points. This has consistently been presented as an example of LEED illogic.
Worry no longer! Installing bike racks is now a prerequisite for all LEED projects, except for those in totally unbikeable locations. The racks have to be safe and convenient — no stashing behind garbage dumpsters. Residential projects provide additional bike storage for their residents.
This prerequisite is both functional and symbolic, providing a visible signal that transportation mode choice is an essential aspect of LEED. Also, creating a bicycle storage prerequisite allows the bar to be raised for performance in the “Bicycle Network, Storage and Changing Rooms” credit.
LT Credit: Bicycle Network, Storage and Changing Rooms
The revamps of this credit have three main effects.
1. The project must be connected to an extensive bicycle network — no “stranded island” locations. A “network” can include moderate-speed roadways.
2. Bike storage for residential projects is doubled, from 15% to 30% of building users.
3. Storage must be 100 feet from building entrances, where previously the standard was 200 yards. Also, storage must be secure (locked).
LT Credit: Site Selection
This credit is now more coordinated with LEED-ND. It carefully exempts incidental or accidental man-made wetlands from protection. Sites with private wells or septic no longer qualify. Projects may also be eligible for an extra point if they are located in high-priority redevelopment areas.
LT Credit: Development Density and Community Access
This credit previously had an “all or nothing” structure. Now it is more graduated. There are two density thresholds, two thresholds for mixed use, and a “synergy” point for projects that combine density and mixed use. The mixed-use section uses walk distance in the calculation — that’s a better measure of walkability, but it can be more complex to calculate. Another way to obtain points in this credit is through LEED-ND certification.
All of these options provide a project with more flexibility. For instance, if a project is located in an area that is not densely developed, it can still earn points if mixed uses are nearby. If a project is not in an infill area, it can still earn points if dense development is nearby.
For freight facilities, there is an interesting set of unique thresholds for access: proximity to a logistics hub, a freeway exit, a rail station, or a rail spur. Projects must meet several of those thresholds to earn points.
LT Credit: Reduced Automobile Dependence
This credit is rewritten with a guiding concept: Having transit stops within walking distance is unquestionably important. But the frequency of transit service is critical as well. Without frequent service, transit is far less viable as an alternative to cars.
Points are alternatively available if the project is located in an area where the amount of vehicle miles traveled is less than the metropolitan average. The thresholds, tables, and definitions in this credit are generally coordinated with LEED-ND.
LT Credit: Walkable Streets
New urbanism design principles provide the foundations of this new credit, which covers a wide range of standards including pedestrian-oriented frontages, spatial definition, spacing of building entries, blank walls, on-street parking, traffic calming, and street trees.
The credit is structured with a combination of required and selected features. Four project features are required. In addition, three out of thirteen features must be selected by the project team. This allows a great deal of flexibility while also ensuring a minimum degree of design performance across several categories.
The features are largely adapted from LEED-ND and tailored to apply to individual buildings. The school-related features are even further tailored to apply to school facilities.
This credit is undeniably complex, as it attempts to condense many LEED-ND credit points into one LEED credit. It represents a pioneering effort to incorporate block-scale and lot-scale urban design into most LEED systems.
LT Credit: Parking Reduction
Previously this credit only referred to local zoning requirements. But what if local zoning ordinances require excessive parking, as many do? In order to identify leadership performance, this credit was rewritten with absolute standards replacing the relative standard. It now refers to the parking ratios listed in the ITE Transportation Planning Handbook, 3rd Edition. I found the tables in the Handbook difficult to read and interpret, so I translated the parking ratios into this Excel spreadsheet, which I hope will be easier to understand.
The ratios listed in the Handbook are very much oriented to suburban, auto-dependent conditions. Therefore, LEED projects earn points by reducing parking below the levels specified in the Handbook.
However, one problem with a one-size-fits-all standard is that it fails to respond to context. In central cities, small-town main streets, and transit station areas, parking demands are typically much lower. The first set of thresholds would not represent leadership performance. Therefore, a second set of tougher thresholds may be applied to projects in dense, mixed use, or transit-oriented locations.
LT Credit: Low-Emitting and Fuel-Efficient Vehicles
The revision of this credit deletes two options: Preferred parking for low-emitting and alternative-fuel vehicles, and provision of alternative fuel fueling stations.
Preferred parking for low-emitting and alternative-fuel vehicles has frequently been identified as a nonperformer. Often the parking policy is not enforced, leading to the embarrassing sight of giant SUVs parked in spaces marked “Low-emitting and fuel-efficient vehicle.” That damages the reputation of LEED, but more importantly it is ineffective as a policy to benefit the environment.
There are several fundamental problems with alternative-fuel vehicles and fueling stations in a nationwide rating system. The most notable are:
1. Various alternative fuels exhibit large differences in terms of the cost, complexity, and performance of refueling stations. Different types of facilities represent different levels of environmental leadership. LEED systems could account for those differences, but doing so would add significant complexity.
2. Alternative-fuel vehicles may provide no environmental benefit compared to highly efficient gasoline vehicles — or worse, alternative-fuel vehicles may cause greater environmental harms than gasoline vehicles, depending on the fuel used and the region of the country where the vehicle is operated. A standard that accounted for these differences would be extremely complex.
The remaining two options in this credit are essentially unchanged.
MR (Materials and Resources) Credit: Whole Building Reuse
While LEED already has credits for reusing portions of buildings, many preservationists have argued for more. This new credit delivers. It provides points for the preservation and adaptive reuse of buildings. A minimum of 75% of the building must be reused; in addition the building must be either listed as historic, or designated as abandoned or blighted.
LEED is the market leader in green building rating systems. But to achieve that position, LEED has chosen to operate under some vexing constraints. LEED rating systems are far from ideal and they contain significant flaws and shortcomings. Even so, LEED remains the most comprehensive, most quantitatively detailed, most thoroughly vetted, and most widely supported, green building rating system on the market. Certainly its ability to recognize environmental leadership is of great value, but I believe LEED’s ability to provide a working, consensus definition of green building is of even greater value.
Kudos should go to the many volunteers who work to improve the LEED rating systems. The draft of LEED 2012 that is now open for public comment reflects the US Green Building Council’s determination to constantly revisit and revise LEED. The USGBC aims to respond to changing market conditions, empirical evidence, theoretical understandings, and criticism, compliments, and comments. The draft LEED 2012 systems are a successful expression of that policy.
The USGBC’s LEED Rating System Development web page includes all of the LEED 2012 draft documents, as well as links to the public comment page, FAQ, forum, and other resources.
Aurbach, Laurence, An Introduction to LEED-ND for CNU Members. PedShed Blog, 26 July 2009.
Roberts, Tristan, Your Guide to the New Draft of LEED. Environmental Building News, 8 November 2010. See also Comment on the New LEED Rating System Draft to be Released in 2012 that appears on leeduser.com.
USGBC Board of Directors, Foundations of LEED. 17 July 2009.
USGBC, LEED Rating System Development: Frequently Asked Questions. 8 November 2010.
USGBC, U.S. Green Building Council Strategic Plan 2009 – 2013. 9 October 2008.