Transportation Energy Use

Created:
Thu, 2011-03-31 12:33

The “Normal” Home In The Transit-Friendly Neighborhood Is Greener Than The LEED Platinum Home in the ‘Burbs

Hey you – with the newly-remodeled, LEED Platinum home in the ‘burbs, the shiny Prius sitting in the drive and the reusable grocery bags full of Whole Foods purchases – you feel pretty eco-angelic don’t you?

And certainly these efforts are an important step towards reducing our greenhouse gas emissions, built environment impact and increasing the overall sustainability of the world.

However, a new study shows that a traditionally-built home, and standard-mileage vehicles, located in a transit-oriented community (a community with easy, effective and efficient access to low-emission or public transportation) has a lower total energy footprint that an Energy Star home in the far-flung suburbs.

Consider the potential energy savings of these three homes that the study looked at:
1. 30-38% for 20% more efficient homes and 37 mpg vehicles in the suburbs
2. 38-50% for conventional efficiency homes and cars in transit-oriented neighborhoods
3. 54-64% for 20% more efficient homes and 37 mpg vehicles in transit-oriented neighborhoods

Clearly, the deciding factor in terms of overall energy footprint is the access a home has to alternative forms of transportation like:

  • biking
  • walking
  • subways
  • light rail
  • bus
  • train
  • trolley

 

So What Is Transportation Efficiency?
Consider how you get to the grocery store. Do you walk, drive, take a bus or bike? Each of these modes of transportation requires a different amount, and different type, of energy (i.e. foot energy versus gas energy). Transportation Energy Intensity is the amount of energy (primarily gasoline if we’re talking about vehicle commuting) that it takes to get people to a building.

To conceptualize this, consider a skyscraper in Manhattan and a shopping mall in Short Hills, New Jersey. While there are probably more people in the skyscraper at 3 PM on a Thursday, each person at the shopping mall drove their gas-guzzling SUV some distance to arrive at the mall. Most of the Manhattanites walked, took the subway or bus, or maybe grabbed a taxi. The total energy use of the more dense area (Manhattan) is lower.

The transportation energy intensity of any building is easily calculated using a formula and the variables of commute distance, fuel economy, work days per year, gross square footage per employee, and commuting transportation mode. For most buildings, even the green ones, transportation energy exceeds building energy by 30%.

Transportation planning has long been absent from the conversations about building impact and design. However, that is changing as cities like Portland, Austin and Boulder, Colorado beef up their urban planning efforts. As a testament to the success of such programs, urban planners predicted that Portland’s light rail systems would serve 3,500 riders a week when it was designed in 2001. Today it serves 9,000 riders a week.

Why’s It Matter If I Drive My Tahoe SUV?Transportation energy use in the United States is huge. In 2008, transportation and associated energy use consumed 28.5% of the total national energy consumption. The transportation sector’s overall contribution to carbon dioxide emissions is 32.9%. This is higher than the contribution of the commercial, industrial and residential sectors.

The problems with transportation are not limited to greenhouse gas emissions. Studies show that land use development is occurring at a faster rate than population growth. In other words, we’re sprawling.

The more roads and highways we build the more we contribute to:

  • Water pollution: Impervious road surfaces increase runoff filled with pollutants (lawn fertilizer, industrial pollutants, etc) that damage lakes, rivers and oceans. This increases water temperatures and makes waterways unsuitable for cold-water fish like trout.
  • Ecosystem fragmentation: Highways fragment ecosystems, destroy habitat and disrupt migration patterns.
  • Heat Islands: Paved areas create “heat islands” that have higher temperatures solely because of the concentration of concrete. These heat islands increase smog and air-conditioning requirements.

 

OK, So What Do We Do About This Traffic Jam?
It is possible to design neighborhoods and site buildings to use transportation options to their fullest potential. The study considered the following factors as the most important ways to reduce the transportation energy use associated with a building.

  • Density: The more people per acre, the less per capita travel
  • Transit Availability: Public transportation must be available, convenient and comfortable
  • Diversity: The more commercial, residential and retail services there are in a concentrated area, the easier it is for public transportation to effectively meet people’s needs
  • Parking Management: Expensive or limited parking incentivizes public transportation.
  • Walkability: It must be possible to walk, but it must also be safe, comfortable, relaxing and enjoyable. Think slower traffic, security, outdoor cafes, shade trees, etc.
  • Connectivity: Make it easier to walk by eliminating “super blocks” and adding pathways and cut-offs for pedestrians.
  • Bikeablity: Make it safer, easier and more comfortable (I’m seeing a pattern here).
  • Efficiency: Making motorized means of transportation more efficient by encouraging mass transit, hybrid vehicles and ride shares.

 

What Does it All Mean To Me?
To be certain, it’s a daunting task to think about redesigning our transportation systems.

The environmental implications of reduced transportation energy use are undeniable. By reducing our dependence on cars, we reduce our cost of transportation, reduce a significant portion of greenhouse gases and break our addiction to foreign oil supplier by hostile and controlling dictators.

However, well-designed transportation also improves individual quality of life. Think about how much more enjoyable it is to stroll to work along a tree-lined street, birds chirping and children laughing, than it is to curse the traffic-clogged highway and hour-long commute that spit you out at your office.

If you are interested in learning more about ways to reduce transportation energy use, a certification in LEED Neighborhood Design is a great place to start. This class is valuable for anyone considering the citing of your next home or commercial building. It also leads to careers in urban planning and transportation planning, or serves as an important addition to the resume of current planners.

Whether by switching your own mode of transportation, or helping redesign your entire city, it’s time to consider this increasingly important aspect of environmental sustainability. After all, with a population growth of 40 million people in the next twenty years, I’d hate to be stuck in rush hour traffic then. So jump on the bandwagon – or bus, of light rail, or bike – and start thinking about ways to help.

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