Block and Lot Standards
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DESIGN..................... Site Framework
PROCESS
IMPLEMENTATION
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Credit | Urbsworks, Inc.
Tool Intent
TOOL DESCRIPTION
The block is a central element of urban planning and urban design. Blocks are the setting
for buildings and form the basic unit of the urban fabric across neighbourhoods, cities, and
regions. Blocks are usually “built-to,” with buildings fronting the edge of the block to varying
degrees; therefore, they form the physical containers or “street walls” of public space.
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Most cities contain a variety of sizes and shapes of urban blocks. For example, many
pre-industrial urban areas across the world have irregularly-shaped street patterns and urban
blocks, while urban areas based on grids have much more regular arrangements. The block
is defined by the street and open space network that surrounds it, and the character of the
street network is a function of the form, character, and intensity of the block that fronts it.
The lot is the fundamental component of building blocks. Urban blocks may be subdivided
into any number of smaller lots or parcels of land, usually in private ownership or other forms
of tenure.
There are several rules of thumb for defining appropriate block and lot standards in a
greenfield development:
› Block perimeters and block face lengths should balance pedestrian and bicycle comfort
and mobility, emergency response times, transit accessibility, freight access, and
automobile movement.
› Block perimeters and block face lengths should maximize real estate value by creating the
greatest number of high-value perimeter-facing lots.
› Block sizes and lots of modular units or flexible scales should be able to be assembled or
sub-divided into useful areas for development that meet near- and long-term economic
needs, and can respond to changing real estate market demands.
› Block and lot standards should result in a street network with high connectivity and meets
objectives for street network density, intersection density, link-node ratio, pedestrian route
directness, effective walking area, and block density.
› Block areas and perimeters should be able to support a range of building types for
employment, commercial, mixed-use, live-work, and residential uses.
› Block areas and perimeters should be able to support a range of housing formats.
› Configuration of blocks should account for access to services, such as rear lanes for
access to parking, garages, and trash/recycling.
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Block and lot standards set
a framework for the physical
structure and massing of future
development and intensification
that is integrated with the local
context and considers the
needs for civic investment in
infrastructure and the public
realm.
Block and lot standards are typically used by
professional planners and urban designers
employed by municipalities. They may also be
used by architects, landscape architects, and
attorneys in private practice on behalf of a large
development (see New Columbia), and can be
used by citizens, neighbourhood associations,
and developers for providing guidance as to their
preferred development patterns.
USERS
Municipal Officials
Municipal Planning Staff
Planning + Design Professionals
Engineers
Land Developers
Landowners
Community Members
O2 Planning + Design Inc.
Block and Lot Standards
Optimally, blocks should be small enough to maximize development opportunity, street
network connections, and street frontages, but not so small that the amount of land dedicated
to the street network and surrounding public realm is a cost burden out of balance with the
benefits of developments in the private realm.
CASE STUDIES | BEST PRACTICES
New Columbia, Portland, Oregon
Where larger blocks are needed to accommodate large footprint buildings (e.g., large-format
retail or certain employment, institutional or mixed-use buildings) or temporary surface
parking lots, special blocks can be created that deviate from the defined standard. Pedestrian
and bicycle connections should still be provided through large blocks or superblocks to
ensure transit accessibility and neighbourhood walkability. The spacing, width, and design
of these connections should be allow future development of the blocks, especially through
temporary surface parking lots.
Large blocks can often be accommodated in areas where topography or natural features
prevent maximum block length and perimeter standards from being met.
Benefits
› Connections to and effective use of existing infrastructure can promote community capital
investments that are concentrated, targeted, and efficient. Maintenance and operations
costs are also better tied to land use.
› Emergency response is improved by concentrating development and providing network
connections that are less subject to interruption or disruption.
› Public health is promoted by providing an environment where walking, bicycling, or transit
are viable alternatives to automobile trips.
› Infrastructure investment is appropriately scaled, compact, and efficient.
› The modular nature of lot and blocks provides flexibility that allows the intensity of
development to increase or decrease over time through consolidation and subdivision.
› Standards can adapt to topography and natural features by allowing adjustment in the
size of blocks and the network of streets.
WHEN IN THE PROCESS IS IT USED?
Policies that establish goals and objectives for block perimeter, block dimensions, block
orientation, and network connectivity can be developed early in the regional or greenfield
planning process. These policies do not need to be project-specific. Projects should be
allowed the flexibility to adjust established policy to specific local conditions such as
topography, hydrology, and/ or habitat.
Location: Portland, Oregon
Project Size: 82.5 acres
Description: City of Portland set new standards for the New
Columbia project, requiring a minimum density of nearly 18
units per acre, while the surrounding neighbourhood had a
much lower intensity of development, with an average of
five units per acre. Regional and City standards for block
perimeter, block length, and street and pedestrian connectivity
set bookend limits for minimum and maximum block
development.
In this case, the developer needed a high degree of flexibility
regarding the number, types, and distribution of units on
the site. The design employed a modular system of lot sizes
that allowed each block to support a single dwelling, duplex,
rowhouse, or garden apartment within the development
context of any individual block. Using this approach, it
was possible to meet the requirements for density while
integrating the development with the form of the lower
intensity neighbourhood. Modular lots, combined with
common green space, effectively extended the functional
length of each block face. This modular approach allowed for
the preservation of over half of the 430 trees on site.
One of the initial project goals was to integrate a new public
elementary school within the original 82-acre site. The
modular lot size and flexible block development pattern
allowed for the dedication of 2.5 acres for the development of
a new school without any loss of residential units compared
to a standard plan. In this case, residential density originally
assigned to the block where the school was constructed was
redistributed to other blocks by consolidating lots.
Each lot in the development had an assigned minimum and
maximum density that was a condition of the recorded plat.
This assured the City that minimum density targets would be
met when the project was fully built-out. The client had ongoing flexibility throughout the the project to make necessary
adjustments in response to market demands and economic
conditions.
Planning + Design: Mithun; Robertson Merryman Barnes
Architects Inc.; Michael Willis Architects; Urbsworks Inc.
Developer: Housing Authority of Portland
New Columbia
Credit | Urbsworks, Inc.
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Block and Lot Standards
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Credit | Urbsworks, Inc.
RELATED TOOLS
Residential Street Patterns
Transit-Ready Planning
Connectivity Index
The Neighbourhood Unit
Walkability Audit
LEED ND Rating System
Bikeability Audit
LEED ND Rating System
Tools for Transitioning to Mixed-Use, Higher Intensity Development Over Time
Credit | Urbsworks, Inc.
ADDITIONAL RESOURCES
New Columbia (http://casestudies.uli.org/CaseStudies/C038010.htm)
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O2 Planning + Design Inc.