INSTITUTE OF TRANSPORTATION STUDIES
UNIVERSITY OF CALIFORNIA, BERKELEY
Toward Green TODs
Robert Cervero and Cathleen Sullivan
WORKING PAPER
UCB- ITS- VWP- 2010- 7
August 2010
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Toward Green TODs
Robert Cervero and Cathleen Sullivan
August 2010
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Abstract
Green Transit Oriented Developments ( TODs) shrink environmental footprints by
reducing Vehicle Kilometers Traveled ( VKT) and incorporating green urbanism and
architecture in community designs. Synergies from combining TOD and green urbanism
derive from: increased densities, which promote transit usage and conserve
heating/ cooling expenses; mixed land uses which promote non- motorized transportation
and limited- range electric vehicles; reduced impervious parking services matched by
increased open space and community gardens; and, opportunities for generating solar
power from photovoltaics atop rail- stop canopies. The carbon footprints of Green TODs
can be 35% less than those of conventional developments. Experiences with Green
TODs are reviewed for urban regeneration projects in Sweden, Germany, and Australia.
The paper concludes with ideas on moving Green TODs from theory to practice.
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1. The Idea of Green TODs
TOD, or Transit- Oriented Development, has gained popularity worldwide as a
sustainable form of urbanism ( Cervero, 2008; Renne, 2009). It typically features
compact and mixed- use activities configured around light or heavy rail stations,
interlaced by pedestrian amenities. TODs are one of the more promising tools for
breaking the vicious cycle of sprawl and car dependence feeding off each other, replacing
it with a virtuous cycle: one where increased transit usage reduces traffic snarls and
compact station- area development helps to curb sprawl.
A new ultra- environmentally friendly version of TOD – what I am calling “ Green
TOD” -- is taking form in several European cities. Green TOD is a marriage of TOD
and Green Urbanism ( Table 1). The combination can create synergies that yield
environmental benefits beyond the sum of what TODs and Green Urbanism offer
individually. TOD works on the VKT- reduction side of shrinking a city’s environmental
footprint – i. e., reducing Vehicle Kilometers Traveled, a direct correlate of energy
consumption and tailpipe emissions. VKT declines not only from rail travel by those
living and working in TODs but also by converting trips that would be by car to off- site
destinations with on- site walking and cycling. Green Urbanism reduces emissions and
waste from stationary sources, in the form of green architecture and sustainable
community designs ( Beatley, 2000; Newman et al., 2009). With Green Urbanism, pocket
parks and community gardens replace surface parking. Renewable energy might come
from solar and wind as well as bio- fuels created from organic waste and wastewater
sludge. Recycling and reuse of materials, insulation, triple- glazed windows, bioswales,
and low- impact building materials further shrink the footprint of Green TODs. In
combination, the co- benefits of TOD and Green Urbanism can deliver energy self-sufficiency,
zero- waste living, and sustainable mobility.
Synergies that accrue from combining TOD and Green Urbanism could occur in
several ways:
( 1) Higher Densities. The higher community densities needed to fill the trains
and buses that serve TODs also reduce heating and cooling expenses
from the embedded energy savings of shared- wall construction. The
financial savings from lower energy bills and reduced transportation costs create
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higher market demand for compact living in green TOD buildings.
( 2) Mixed Land Uses. The inter- mixing of housing, shops, restaurants,
workplaces, libraries, day- care centers, and other activities place many
destinations close together, thus inviting more walking and bicycling – not
only to access rail stops but also for neighborhood shopping and socializing.
Green TODs might also help to grow infant- industries like the development of
lithium- ion electric vehicles ( EVs). Limited range EVs can serve a large share of
trips in mixed- use settings, not unlike golf- cart communities. One could imagine
a future of hydrogen- fueling and electric- battery swap depots in a green
community wrapped around a central rail station.
( 3) Reduced surface parking and impervious surfaces. Surface parking, which
can consume half the land of many suburban multi- family dwelling complexes
( Diasa, 2004), is replaced by more green space for play, socializing, and
interacting with neighbors ( Figure 1). Shrinking parking’s footprint reduces heat-island
effects and water pollution from oil- stained run- off into streams. Less
impervious surfaces of concrete and asphalt help recharge groundwater and
replenish urban aquifers, thereby allowing greener and healthier gardens. While
the common perception is that TODs appeal to non- traditional households ( e. g.,
singles; young, childless professional couples, empty- nesters and retirees) ( Center
for TOD, 2008), Green TODs can be kid- friendly. The interiors of projects are
given over to communal gardens, playgrounds, tot- lots, and play- inviting open
space rather than parked cars. Reducing the car’s dominance can lower
accident rates, noise levels, and air pollution – and creates much more enjoyable
environments for kids to play. Having safe and secure interiors for kids to play
becomes a form of defensible space ( Newman, 1996), allowing the kind of natural
surveillance embraced in the writings of Jane Jacobs ( 1961) and others.
( 4) Solar energy production at stations. With TODs, stations areas are often
community hubs, places not only to get on and off of trains and buses but also to
congregate, socialize, and take in community life ( Cervero, 1998; Bertolini,
1996). Surface train and bus depots often feature overhead canopies that provide
shade and weather protection. Photovoltaic panels and even small wind turbines
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can be placed atop canopies at stops to generate electricity that is piped into
surrounding homes and businesses through a smart grid. Solar energy can also
power light- rail cars, and recharge batteries of plug- in hybrids at carsharing
depots and electric buses dwelling at stops during low demand period ( as
currently done with Tindo solar- electric buses in Adelaide, Australia).
Table 1. Possible Environmental Benefits of Green TODs
Figure 1. Green TOD in Rieselfeld, Germany: Gardens and play areas replace surface
parking.
TOD
Mobile Sources
Green Urbanism
Stationary Sources
• Transit Design
World- class transit
( trunk & distribution)
Station as hub
• Non- motorized access
( bikepaths, ped- ways)
• Bikesharing/ Carsharing
• Minimal Parking
( reduced land
consumption, building
massing &
impervious surfaces)
• Compact, Mixed Uses
• Energy self- sufficient
( renewably powered –
solar, wind turbines)
• Zero- waste ( recycle;
re- use; methane
digesters; rainwater
collection for irrigation
& gray- water use)
• Community gardens
( compost, canopies)
• Buildings: Green Roofs,
Orientation ( optimal
temperatures),
Materials
( recycled; low impact)
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As noted, the environmental benefits of TOD by itself, even absent green
urbanism and architecture, comes from per capita VKT reductions, courtesy of more
transit trips to out- of- neighborhood destinations and more non- motorized travel within
( Cervero, 2007; Ewing and Cervero, 2010). However benefits also accrue from policy
initiatives like bike- sharing and car- sharing, which research shows prompt residents to
shed private cars ( Cervero et al., 2007). In TOD settings, bikesharing can solve “ the first
and last mile problem” – getting to and from stations from origins and destinations that
are beyond an easy walk. Sharing bikes becomes all the more attractive when extensive
networks of cycleways and paths exist, as borne out by experiences in cities like
Copenhagen and Stockholm, where more than 30% of access trips to suburban rail
stations are by bicycle, even in inclement weather ( Rietveld, 2000; Rietveld and Daniels,
2004). As reviewed in case experiences later in this paper, carsharing also plays a
pivotal role in Green TODs. By making the marginal cost of using a car more evident,
carsharing prompts “ judicious automobility” – members tend to use cars more selectively
and when it has clear advantages over alternative modes ( e. g., grocery shopping,
weekend excursions to the countryside) – and accordingly end up significantly reducing
their VKT. The combined effects of substituting car trips for transit, walking, and
cycling trips can reduce the VKT per capita of those residing in Green TODs relative to
conventional suburban development by an estimated 40% to 50% on the mobility side of
the environmental and carbon equation ( Cervero, 2007; Ewing and Cervero, 2010;
Cervero et al., 2007). Green buildings and green urbanism further reduce energy
consumption and carbon emissions from stationary sources relative to conventional
development by even higher shares – in the range of 50% to 60%, based on some of the
experiences reviewed later in this paper. The synergies of pursuing TOD and green
urbanism in combination shrink environmental footprints even more. Back- of- the-envelope
calculations suggest reductions in annual CO2 emissions equivalent per capita
among those residing in Green TODs relative to conventional development patterns fall
in the 29 to 35 percent range. 1
1 This estimate is based on assigning 32 percent of end- use carbon emissions from fossil fuel
consumption of urban residents to the surface transportation sector and 22 percent to domestic
household consumption, such as for electricity power generation, heating, and cooling. These
represent pro- rata estimates of carbon dioxide emissions by end- use sector in the U. S. in 2008, as
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Not many TODs have been consciously designed as “ Green TODs,” certainly not
in the United States. More typical are sustainable communities that promote renewable
energy and recycle waste and that also have very good transit services. Similarly, many
places that bill themselves as eco- communities do not always embrace and showcase
public transit to the degree they could. Unlike some of the most successful TODs where
the station and its immediate surroundings are often the centerpiece of a community
( Cervero, 1998), the stations of eco- neighborhoods are sometimes found on the
community’s edge.
The next section reviews several case experiences where transit forms the
backbone of eco- communities. In these instances, synergies abound from bundling TOD
designs with green architecture and green urbanism. In addition to describing the built
forms and Green TOD attributes of these places, evidence on environmental benefits is
reviewed. The paper concludes with suggestions for moving Green TOD from theory to
reality.
2. Case Experiences with Green TOD
The cases reviewed in this section – Hammarby Sjöstad in Stockholm, Sweden;
the Rieselfeld and Vauban districts of Freiburg, Gemany; and Kogarah Town Square in
Sydney, Australia – come as close to the ideal of a Green TOD as can be found today.
Since descriptions and background details of these projects can easily be found on the
Internet, the focus here is on isolating elements that make them Green TODs. Where
available, statistics on the projects’ environmental benefits are presented.
recorded by U. S. Environmental Protection Agency ( 2010). Carbon dioxide represented 85% of
human- induced ( anthropogenic) greenhouse gas emissions in the U. S. that year. Other savings
would accrue that are not explicitly accounted for in these calculations of end- use emissions, such
as reduced transportation costs from shipping and marketing food that, as a form of food security,
is instead grown in community gardens.
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2.1 Hammarby Sjöstad: Stockholm, Sweden
Hammarby, a brownfield redevelopment in the city of Stockholm, is an example,
par excellence, of marrying TOD and green urbanism. The combination of railway
services, car- sharing, and bike- sharing has dramatically reduced vehicle- kilometers
traveled of Hammarby Sjöstad’s residents and correspondingly greenhouse gas emissions
and energy consumption. And the design of an energy self- sufficient and low- waste
community has shrunk the project’s environmental footprint. Today, residents of
Hammarby Sjöstad produce 50% of the power they need by turning recycled wastewater
and domestic waste into heating, cooling, and electricity.
The development of Hammarby Sjöstad marked an abrupt shift in Stockholm’s
urban planning practice. After decades of building new towns on peripheral greenfield
sites, Hammarby Sjöstad is one of several “ new- towns/ in- town” created following
Stockholm’s 1999 City Plan that set forth a vision of “ Build the City Inwards.”
Consisting of some 160 hectares of brownfield redevelopment, Hammarby Sjöstad today
stands as Stockholm’s largest urban regeneration projects to date. Table 2 outlines
Hammarby Sjöstad’s Green TOD features.
Green Transportation
A tramway (“ Tvärbanan”) runs through the heart of the community along a 3- km
boulevard ( Hammarby Allé and Lugnets Allé) ( Figure 2). Taller buildings ( mostly 6- 8
stories) cluster along the transit spine, and building heights taper with distance from the
rail- served corridor. Trams run every 7 minutes in the peak and provide 5- minute
connections to Stockholm’s metro underground network and commuter trains. Rail
stations are well- designed, fully weather protected, and provide real- time arrival
information. Hammarby Sjöstad’s buses, moreover, run on biogas produced by local
wastewater processing.
Parks, walkways and green spaces are also prominent throughout Hammarby
Sjöstad. Where possible, the natural landscape has been preserved. Bike lanes run along
major boulevards, ample bike parking can be found at every building, and bike and
pedestrian bridges cross waterways. Design features that are integral to TOD, like
buildings that go up to the sidewalk line ( i. e., no set- backs), offer comfortable and secure
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Table 2. Green TOD Attributes of Hammerby Sjöstad
Built
Environment
Green Transportation Green Urbanism
Infrastructure
Programs
& Policies Energy
Open Space, Water
& Stormwater
* Brownfield
* Infill
* Former Army
Barracks
• High density
along light rail
boulevard
( 8 stories)
• TOD: Mixed use
with ground‐ floor
retail‐ wide range
of goods and
services
* “ Tvärbanan” light rail
line: 3 stops in District
‐ 5 minutes to major station
‐ 10‐ 30 minutes to all parts
of Center City
‐ 7‐ min peak headway
* 2 Bus lines
* Ferry
* Bike lanes & bike and
pedestrian bridges
* Ample bike parking at
every building
• Car‐ sharing‐ 3
companies, 37 vehicles
• Near congestion toll
boundary
• Pedestrian‐ friendly
design/ Complete
Streets
• Transit‐ Boulevard
is focus of
activity/ commerce
• Grid streets
increase
connectivity/
calm traffic
• Convenient Bike
parking/ storage
at every building
• Waste converted to
energy:
‐ Food waste &
wastewater sludge
converted to biogas
& used for heating
‐ Combustible waste
burned for energy &
heat
‐‐ Paper recycled
* Heat recaptured for
reuse
* Combined heat &
power plant
• Low‐ energy
construction &
energy saving
measures
‐ Efficient appliances
‐ Maximum
Insulation &
triple glazed
windows
* Stormwater treatment
‐ Rainwater collection
‐ Maximum permeable
surfaces
‐ Purify run‐ off through soil
filtration
* Ample open space:
‐ Inner courtyards
‐ Parks
‐ Playgrounds
‐ Green median
‐ Borders large nature
reserve with ski slopes
* Preservation of existing
trees & open space
* Reduced water flow faucets
& low‐ flush toilets
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walking corridors with clear sight- lines. As in the case of Hammarby Sjöstad, they also
bring destinations together, and through side friction end up slowing traffic.
The presence of 3 carsharing companies which together provide access to 37 low-emission
vehicles has further reduced the need for owning a car in Hammarby Sjöstad.
Also, the project was designed at just 0.25 parking spaces per dwelling unit, though this
rate has inched up some in recent years. All commercial parking, moreover, is for a fee,
and rates discourage long- term parking. The neighborhood also sits just outside
Stockholm’s congestion toll boundary, which adds a further incentive to use public
transport, walk or bike when heading to the central city.
Figure 2. Transit Spine in Hammarby Sjöstad
Green Urbanism
Hammarby Sjöstad’s green urbanism is found in energy production, waste and
water management, and building designs. The highest standards of energy efficient
building are used. All building standards in Sweden are highly energy efficient, being a
Nordic country with high heating costs and very high energy prices. The district heating
network in Stockholm provides 80 % of all heating needs, substantially reducing energy
loss in the heating system. Eighty percent of energy for this heating system comes from
renewable sources. The use of district cooling reduces carbon dioxide emissions in
Stockholm by about 50,000 tons annually. After heat has been extracted from the warm,
purified waste water, the remaining cold water is used for district cooling, such as
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replacing energy- guzzling, air- conditioning systems in office buildings.
Hammarby Sjöstad’s energy platform is cutting edge, even by Stockholm
standards. The energy use of buildings in Hammarby Sjöstad has been set at 60
kWh/ year, a third less than for the city as a whole. All windows are triple glazed and
walls thoroughly insulated. Other conservation measures include extra heat insulation,
energy- efficient windows, on- demand ventilation, individual metering of heating and hot
water in apartments, electrically efficient installations, lighting control, solar panels, fuel
cells, reduced water flow, and low- flush toilets.
The ecological feature of Hammarby Sjöstad that has garnered the most attention
is the fully integrated closed loop eco- cycle model. This clever system recycles waste
and maximizes the reuse of waste energy and materials for heating, transportation,
cooking and electricity. Hammarby Sjöstad’s waste management/ re- use involves the
following:
• Glass, metals and plastics are recycled.
• Combustible waste is incinerated and recycled as heat and electricity.
• Organic waste is composted and turned into soil or converted into biogas.
• All newspaper is recycled into new paper.
The three latter types of waste are dealt with through a stationary vacuum system for
solid waste called the “ ENVAC system.” At each building, residents can deposit waste
into vacuum tubes where it is transported to pick- up locations. This minimizes truck
traffic through the development, thereby lowering emissions, allowing for narrower
streets and less disruption from truck traffic. Waste is also converted into energy for
district heating and cooling – in the form of biogas created from treated wastewater
( produced in the wastewater treatment plant from digestion of organic waste sludge) and
the incineration of combustible waste. In addition, biogas is used to run the buses and
biogas cookers are installed in some 1,000 apartments. Solar hot water and solar PV cells
are installed on many buildings. Solar panels provide 50% of the hot water needs for
many building, although solar installations meet a small share of the development’s
energy needs due to the Nordic climate.
Also impressive is Hammarby Sjöstad’s approach to water management. All
storm water, rainwater and snowmelt is collected, purified locally through sand fiber,
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storm water basins, and green roofs and released in purified form into a lake. A
preserved oak forest, ample green surfaces, and planted trees help collect rain water to
ensure cleaner air and provide a counterbalance to the dense urban landscape.
Impacts
Based on several environmental impact assessments, secondary data, and
interviews, the environmental impacts of Hammarby Sjöstad’s form of Green TOD are
assessed below. 2 According to the initial assessment, when Hammarby Sjöstad was
roughly half built out it had already achieved a 32- 39% reduction in overall emissions
and pollution ( air, soil and water), a 28- 42% reduction in non- renewable energy use, and
a 33- 38% reduction in ground level ozone relative to comparison communities.
Buildings and transportation accounted for most of the reduced environmental impacts.
The primary environmental benefit of improvements from Hammarby Sjöstad’s
buildings came from efficiencies in heating ( i. e., recycled organic and combustible waste
transformed into heat), use of water, and processing of wastewater. The project’s
reductions relative to conventional development were: ( 1) emissions and pollution ( air,
soil and water) -- 40- 46%; non- renewable energy use -- 30- 47% ; and water consumption
2 Between 1997 and 2002, a full “ Environmental Impact Profile” of Hammerby Sjöstad was
commissioned by the City of Stockholm and conducted by Grontmij AB ( 2008). For drawing
comparative insights, a “ reference level” was defined: “ The reference level used to measure the
anticipated reduction in environmental impact in Hammarby Sjöstad is the technology level
current in the early 1990s, when planning work on the city district began” ( Grontmij, 2008). For
our purposes, this reference level can be viewed as conventional new development in the
Stockholm region at the time. Hammarby Sjöstad is far more built out today so the results from
nearly a decade ago could very well have changed ( most likely in the direction of even larger
differentials relative to the “ reference level” since the project has matured and expanded). At the
time the assessment was conducted, approximately 5,000 apartment units had been constructed,
less than half of the total development today. This was a full life- cycle evaluation that included
energy expenditures and waste tied to site clearance, construction, and operation phases of the
development. In 2008, the City of Stockholm also commissioned the Department of Industrial
Ecology at the Royal Institute of Technology, KTH, in Stockholm to assess the environmental
impacts of Hammarby Sjöstad. The starting point of the evaluation was the environmental
program of Hammarby Sjöstad from 1996 and the aim was to gather the most important results
and experiences that the City of Stockholm should bring into the planning of new urban districts.
Only preliminary results from this second assessment are presently available.
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-- 41- 46%. Similar to the rest of Stockholm, 95% of all waste produced by Hammarby
Sjöstad’s household is reclaimed.
On the transportation side of things, environmental benefits have accrued from
Hammarby Sjöstad’s relatively high share of non- motorized ( walking and bicycling)
trips. In 2002, the project’s modal splits were: public transport ( 52%), walking/ cycling
( 27%), and private car ( 21%) ( Grontmij, 2008). Non- car travel shares are thought to be
considerably higher today and even in 2002 well exceeded that of comparison suburban
neighborhoods of Stockholm with similar incomes ( Table 3). 3 Residents’ transit modal
splits even exceed those of inner- city Stockholm. Also, 62% of Hammarby Sjöstad’s
households had a car in 2007, down from 66% in 2005 and in line with averages for the
denser, core part of Stockholm city ( Grontmij, 2008). Studies show that residents’
carbon footprint from transportation in 2002 was considerably lower than comparison
communities: 438 versus 913 kg CO2 equivalent/ apartment/ year ( Grontmij, 2008). This
is in keeping with the goal of the city of Stockholm to become fossil- fuel free by 2050.
Another barometer of Hammarby Sjöstad’s environmental benefits is the
relatively healthy local economy – i. e., a higher median household income and lower
unemployment rate relative to the city as a whole in 2006. Also, land prices and rents
have risen more rapidly over the past decade than most other parts of the Stockholm
region. Today, Hammarby Sjöstad is considered to be a relatively desirable and thus
more expensive place to live compared to the inner city and other “ new towns/ in town”.
Overall, Hammarby Sjostad has reduced its environmental impact by around one
third relative to conventional suburban development in Stockholm. This percent will
likely increase over time, at least until Stockholm becomes carbon neutral and fossil free,
currently targeted for mid- century.
3 Many residents and employees of Hammarby Sjöstad use a ferry in combination with other
modes. The ferry accounts for 24% of all trips to and from Hammarby Sjöstad and has increased
walking and bicycling. Modal splits for the ferry are not shown in Table 3 but rather are rolled
into trips made by other modes ( e. g., walk, bike, bus) since ferries represent one leg of multi-legged
( i. e., linked) trips.
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Table 3. Mode Splits for Journeys with destination in Stockholm County
Inner City
Southern Suburbs
Western Suburbs
Hammarby
Sjöstad**
Car 17% 39% 43% 21%
Public Transport 36% 28% 23% 52%
Bike/ Walk 47% 32% 34% 27%
Source: Grontmij ( 2008).
2.2 Rieselfeld and Vauban Districts: Freiburg, Germany
The Rieselfeld and Vauban districts of Germany’s greenest city – the historic
university town of Freiberg – were conscientiously designed to push the envelope of
sustainable urbanism. 4 Both are peripheral redevelopment sites linked to central Freiburg
via the region’s tramway network ( Figure 3). And both embody Freiburg’s aim of
becoming a “ City of Short Distances,” one that allows “ traffic avoidance,” which is
accomplished through mixed land- use patterns and near- ubiquitous public transit.
Rieselfeld and Vauban abide by Freiburg’s obligatory low- energy building
standard of 65 kWh/ m2/ year ( twice as efficient as Germany’s national energy standard).
Both districts also generate heat and power through wood- chip- fueled cogeneration plants
as well as active ( e. g., photovoltaics) and passive ( e. g., building orientation and
architecture) solar energy. Additionally, both developments have comprehensive storm
water management systems that collect rainwater, maximize permeable surfaces through
provision of ample green space, parks and playgrounds, and purify run- off through
bioswales and other soil filtration systems.
4 Freiburg is known as Germany’s solar energy mecca, with the highest solar irradiation in the
country. Over the past two decades, the city has pursued a host of environmental strategies in
transport, energy efficiency and clean energy production, ecosystem protection and management,
and waste and pollution reduction. Thus the Green TODs of Rieselfeld and Vauban are a
manifestation of Freiburg’s larger campaign to be a zero- waste, energy self- sufficient community.
In 1992, Freiburg’s City Council established that all houses built on municipal land would abide
by rigorous low- energy standards and take advantage of passive and active solar. Today, all non-recyclable
waste is either incinerated or fermented for bio- mass energy. The city’s volume of
garbage is markedly lower than the national average.
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Figure 3. Rieselfeld and Vauban districts of Freiburg, Germany
Rieselfeld
Planned in the early 1990s, Rieselfeld – with a population of 9,100 residents
living on 90 hectares – is today nearing completion, around 90% built out. The planned
community, which sits on a former wastewater leach field, was designed and marketed
specifically for ecologically- minded families. By suburban standards, Rieselfeld has
fairly high densities, and through its street designs gives priority to non- auto modes. The
community boasts low- energy building construction, a district heating network powered
by a combined heat and power plant, decentralized solar energy, and storm water
management. Rieselfeld’s Green TOD features are summarized in Table 4.
Rieselfeld can be described as “ transit- led development” ( TLD). A tramway
extension to Rieselfeld opened in 1997, a year after the first families had moved in and
when there were only 1000 inhabitants. The presence of 3 tramway stations enabled
urban growth to wrap itself around rail nodes. With 7- minute peak headways, residents
can reach Freiburg’s core within 10 minutes.
Reiselfeld is also known for its “ barrier- free” living environment, marked by high
permeability and connectivity in its layout ( Figure 4). Extensive bikeways and ped- ways
-- along with narrow streets that slow traffic, a grid pattern, and preferential treatments
for trams, buses, pedestrians, and bicycles at intersections -- have promoted sustainable
mobility. The district has adopted an uncontrolled “ shared space” traffic system that sets
maximum car speed at 30 kph and includes many shared “ play” streets, which give
priority
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Table 3. Green TOD Attributes of Rieselfeld District
Built
Environment
Green Transportation Green Urbanism
Infrastructure
Programs
& Policies Energy
Open Space, Water
& Stormwater
* Brownfield
* Contiguous to edge
of City
* Former wastewater
leach field serving
as greenbelt
* Compact
‐ Highest density along
Tramway
> 90% multi‐ family
buildings
= 5 stories
* Mixed use with
ground‐ floor retail
* TOD: main street is 2/ 3
mile tram corridor
* Tram: 3 stops in District
* 7‐ min peak headway
* 15‐ 20 minutes to Core
* Extensive Bike and
Pedestrian paths, access
to City center via
separated bike paths
* Car‐ sharing
* “ Barrier‐ free” living, high
permeability/
connectivity
* Uncontrolled shared space
traffic system:
‐ Shared “ play” streets,
children have priority
* No stop signs, right yield
* Priority for trams,
pedestrians & bicycles
* Car traffic limited:
‐ Maximum traffic speed
30 kph
‐ Traffic calming & narrow
streets
‐ Grid layout prevents cut‐through
traffic
* Convenient bike parking/
storage
* Park‐ and‐ ride facilities
* Parking ratio: 1: 1 in
underground garages
• Active and Passive
Solar ( architecture/
orientation & PV)
* Low‐ energy
construction
* District Heating
* Combined Heat and
Power Plant ( co‐generation)
* Energy saving
measures
• StormwaterManagement
system:
‐ Rainwater collection
‐ Maximum permeable
surfaces
‐ Purify run‐ off through soil
filtration
• Ample Open Space:
‐ Inner courtyards
‐ Parks
‐ Playgrounds
‐ Green median
‐ Borders large nature
reserve with
hiking trails
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to children and pedestrians ( Figure 5). Absent any stop signs, a right yield system is used
at intersections. Active living and physical fitness are promoted by a network of parks,
playgrounds, and a natural reserve that surrounds the community.
Figure 4. Rieselfeld District, Freiburg, Germany. Small blocks, ample green spaces, and
a tram line runs through the tree- lined center of the village promote walking and cycling.
Figure 5. Rieselfeld’s Shared Streets.
Vauban
Situated on 40 hectares of land formerly used as a military barrack and inhabited
by 5,000 residents, Vauban is arguably one of the greenest places in the world. The
community is a product of a highly participatory grassroots process. A number of
activists, feeling that the mobility and energy standards applied in Reiselfeld were
insufficient, demanded that a car- free, ultra- low- energy district be built. Soon thereafter
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Vauban was born. The first residents formed a collective and occupied the former
military barracks. Many still live there today.
Vauban’s Green TOD attributes are summarized in Table 4. The district features
one of Germany’s largest passive house developments and a zero- energy solar village. 5
Vauban’s cogeneration plant is fueled by a renewable source of refuse wood- chips.
There are also 89 photovoltaic systems throughout the development. Due to its ambitious
energy standards, the district performs 90% better than conventional construction in
terms of energy use ( Siegl, 2010). The combined heat and power plant runs at 90%
efficiency compared to a conventional power plant. Additionally, all houses meet and
many exceed Freiberg’s energy standard of the 65 kWh/ year ( including Vauban’s
numerous zero- energy houses and passive houses with solar, which actually produce
more energy than they use).
In addition to its ecological design, Vauban is widely known for its car- restricted
living ( in contrast to Rieselfeld which averages 1.1 parking spaces per dwelling unit).
Most of Vauban’s streets ban cars, and most housing units have no driveway or garage
( Nobis and Welsch, 2003). Cars on the main street are restricted to 30 kph and all other
streets are designed for very low- speed travel ( 5 kph) ( Figure 6). Vauban was laid out so
that all residents live within 2 minutes of a covered bike- sharing kiosk and 5 minutes of a
tram. With the district organized around a tramway spine that is nestled into the
streetscape and 7- minute peak headways, transit has a certain omnipresence in Vauban
( Figure 7).
Vauban’s planners made sure that parking’s environmental footprint was limited.
All parking is unbundled from the price of units, and fees to purchase a space are quite
high at € 17,500/ space. 6 Seventy percent of dwelling units are “ parking- free,” and what
little parking that does exist is sited in two shared garages on the town’s periphery
( Figure 8). Both garages are topped off with solar panels.
5 Vauban exceeds Freiburg’s low energy standard with a voluntary low- energy building standard
of 55 kWh/ m2/ year and a passive house standard of 15 kWh/ m2/ year.
6 The planners of Vauban had to work with the City of Freiburg to develop a special waiver from
the German National parking standard of one space per dwelling unit. A lot had to be reserved in
one corner of the development for a future garage if the need should arise; car- free residents have
to reserve a theoretical space in this yet- to- be- built garage at a much lower price of around 3,000€
compared to 17,500€ for an actual parking space.
20
Table 4. Green TOD Attributes of Vauban District
Built
Environment
Green Transportation Green Urbanism
Infrastructure
Programs
& Policies Energy
Open Space,
Water &
Stormwater
* Brownfield:
Former military
barracks
* Infill
• Compact
‐ = 4 stories
• Mixed use with
ground‐ floor
Retail
• TOD: District organized
around tram spine
* Tram: 3 stops
* 7‐ min peak headway
* Regional rail stop ( Future)
* 2 buses
* 10‐ 15 minutes to City
Center by tram/ bus/
bike
* Extensive Bike and
Pedestrian paths;
access to City Center via
separated bike paths
• Network of off‐ street bike
& pedestrian paths
provides access to all
parts of project
* Parking restricted:
‐ High parking fees
‐ Unbundled parking
‐ 70% of units are “ parking‐free
‐ Access to parking in 2 shared
garages on periphery
* Auto restraints:
‐ 30 kph on main street
‐ Limited access with very low
speeds 5 kph
‐ Street layout allows for very l
little car circulation
• Bike Priority:
covered secure bike parking
within 2 minutes of every
residence
• Car‐ sharing
* Low‐ energy building—
65 kWh/ m2/ year
standard, Voluntary:
55 kWh/ m2/ year;
Passive house: 15
kWh/ m2/ year
* District Heating
• Wood‐ chip fired
Combined Heat and
Power Station provides
all energy
* Solar‐ 89 PV systems
* Zero‐ energy Solar Village
• One of largest passive
house developments in
Germany
• Bioswales, open‐channel‐
trough
system
* Rainwater collection
• Ample Open Space
& permeable
surfaces
* Filtration of
rainwater
* Maintain existing
tree coverage
* Adjacent to creek
biotope
* Green roofs
21
Figure 6. Car- free Streets and Solar Array, Main Plaza of Vauban
Figure 7. Vauban’s Central Tramway line. Source: Melia ( 2007)
Figure 8: Location of Parking Garages, Vauban. Source: Schick ( 2009)
22
Mobility Impacts
The environmental payoff of the pro- transit and bike- ped- friendly policies of
Rieselfeld and Vauban are reflected in statistics. Both districts have low auto use and
ownership. As shown in Table 5, Reiselfeld residents own fewer cars and use transit
more than the typical Freiburg resident. Ninety percent of its residents buy a monthly
transit pass. Because residents’ travel was last surveyed in 2003 before the tramway had
opened, it is difficult to provide an up- to- date account of experiences in Vauban.
However, other indicators suggest that Vauban has very low car use. Only 2.2 of every
ten Vauban residents own a car ( compared to 4.3 for Freiburg as a whole and 3.4 for
Reiselfeld). 7 Also, 57% of Vauban’s adult residents sold a car upon moving to the
district ( Sustainability Office, City of Freiburg). It is notable that low car ownership was
recorded in Vauban before its tram line opened. This very likely reflected the influences
of “ self selection” – i. e., the car- free ethic of new residents. However other factors have
weighed in as well, including the pro- active promotion of other modes, the provision of a
free universal transit pass to some households, and the availability of conveniently
located carsharing. Although recent modal split data are not available, the consensus
view is that transit use has replaced many bike and walk trips ( Siegl, 2010). Most of
Vauban’s residents buy a monthly transit pass and half buy a German National Rail Pass.
Moreover, 75% of car- free households buy the national rail pass, compared to 10% of
Germans nationwide ( Nobis and Welsch, 2003).
2.3 Kogarah Town Square: Sydney, Australia
While European cities can lay claim to having advanced the art and science of
building Green TODs more than anywhere, Sydney’s Kogarah Town Square has made
pretty good headway. Newman et al. ( 2009, pp. 120- 121) cited it as a sustainable, rail-served,
and thriving “ mixed- use development consisting of 194 residents, 50,000 square
feet of office and retail space, and 35,000 square feet of community space, including a
library and town square.” Liberal use of photovoltaic collectors and building orientations
that maximize thermal in- take, along with the close proximity to a train station, has
shrunk the carbon footprint of Kogarah Town Square relative to similar districts in
7 19% of residents had never owned a car, 57% gave up car upon moving to Vauban.
23
Sydney. As with European Green TODs, ample open space wrapped around an attractive
and well- lit town center has contributed to the project’s attractiveness ( Figure 9).
Table 5. Modal Split and Car Ownership Statistics
* Broaddus ( 2009)
** Nobis and Welsch ( 2003).
*** Schick ( 2009)
Figure 9. Kogarah Town Square: Sydney, Australia. Traditional architecture, central
rail stations, and open civic squares.
Mode of
Travel:
Rieselfeld
( 1999)*
Vauban
( 2003)**
Freiburg
( 1999)***
Region: Baden-
Württemberg
Walk 16%
28% car- owning
HHs
33% car- free HHs
23%
Bike 28%
40% car- owning
HHs
51% car- free HHs
27%
Public
Transport 25%
~ 4- 11% ( Before
tram service
commenced)
18%
Car 26%
Car 31%
28% car- owning
HHs
2% for car- free
HHs
Carpool 6%
32%
Car Ownership
per 1000
residents ( 2008)
337 222 431 634
24
3. Conclusion
Green TODs offer a form of urbanism and mobility that could confer appreciable
environmental benefits. They emphasize pedestrian, cycling, and transit infrastructure
over auto- mobility. They mix land uses which not only bring destinations closer but also
creates an active, vibrant street life and interior spaces, instilling a sense of safety and
security. And through building designs and resource management systems, they embrace
minimal waste, low emissions, and to the degree possible, energy self- sufficiency.
The case experiences reviewed in this paper highlight the potential benefits of
Green TOD. While other places in Sweden ( e. g., Mälmo), Germany ( e. g., the Kronsberg
district of Hannover), and Australia ( e. g., Adelaide) have made strides in advancing green
urbanism and transit- friendly development, places like Hammarby Sjöstad, Rieselfeld,
Vauban, and Kogarah have successfully integrated both elements in their community
designs. Green TOD, we note, appear to be catching on elsewhere, such as in Jiaxing,
China and Kaohsiung, Taiwan. Perhaps the most ambitious version is now taking shape
in the deserts of the United Arab Emirates – Masdar City, outside of Abu Dhabi. Besides
being car- free and interlaced by rail at the surface level and personal- rapid transit ( PRT)
and freight- rapid- transit ( FRT) below- ground, Masdar City is to be fully energy self-sufficient,
courtesy of a massive solar farm on the project’s edge. Additionally, all
organic waste is to be converted into biomass, all construction materials are being
recycled, and over the long term the project is to become completely carbon neutral.
Other communities should not necessarily seek to replicate the specific practices of these
places but rather adapt principles of Green TOD to local circumstances and constraints.
Moving beyond the rhetoric to the reality of Green TODs will take money, time,
and political leadership. The built- in structural forces that work against designing safe,
resource- conserving, and pedestrian- friendly districts around transit stations are immense,
particularly in countries like the U. S. Barriers are most likely to come down through
encouraging real- world examples, such as those reviewed in this paper.
One sensible way to help finance Green TODs is through value capture
mechanisms. The degree to which Green TODs create benefits is reflected in land prices,
as experienced in Hammarby Sjöstad. Indeed, land sales were the principal means by
which early rail systems were financed in the U. S. and much of Europe ( Bernick and
25
Cervero, 1997). Today, Hong Kong recaptures the value- added from rail investments to
help finance not only transit infrastructure but the armature of the surrounding
community as well, including open spaces, sidewalks, and green corridors ( Cervero and
Murakami, 2009).
Green TODs will be most effective when planned and designed at a regional level
( Cervero, 1998). The Scandinavian model of TODs as “ a necklace of pearls” offers high
environmental benefits by providing an inter- connected system of walkable, transit-friendly
communities. However, not every rail- transit station should become a Green
TOD, or even a TOD for that matter. Some function best as busy terminal/ transfer
points and logistical nodes, with little if any housing, which is a cardinal feature of TOD.
Some with poor pedestrian connections, such as stops in the middle of freeway medians,
might best be surrounded by surface parking. However for communities aiming to push
the envelope of sustainable urbanism and with a physical and social environment
conductive to transit- supportive growth, the Green TOD model has much to offer.
Critics are apt to label Green TOD as “ social engineering”. In truth, many of
those living in the suburbs of the United States are “ engineered” – forced to drive to get
from anywhere to everywhere, a result of segregated and low- density land- use patterns.
Green TODs provide consumers with more choices on where to live and how to travel.
Increased choices and variety is a good thing, especially given the increasingly diverse
and plural make- up of households in America and other affluent societies. We suspect
that given the opportunity, more and more middle- class households will opt for Green
TODs for lifestyle reasons.
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