Even Flow Traffic for Urban Development
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Even Flow Traffic for Urban Development

In 1900, only 10 percent of the world’s population lived in cities; by 2025, it is projected that 75 percent of us will. Megacities, or those with 10 million or more residents, are growing, and as Parag Khanna, director of the Global Governance Initiative, writes, The 21st century will not be dominated by America or China, Brazil or India, but by the city. Mobility, and specifically transportation is one of the biggest issues facing cities across the world. The economy, the environment, and the standard of living for those within the cities depend upon a more efficient solution.

The Parkway City takes aim at congestion and vastly increases mobility to help cities move into the future. The benefits of turning a city into a Parkway city include

  • Economic growth and diversity as a result of increased mobility to all income levels.
  • Improved living standards.
  • Reduced cost of living.
  • Reduction in energy costs.


How does a city achieve this? Here’s just one way: we’ve all read tips and tricks to reduce gas mileage, and we know that maximum fuel efficiency is attained at 45 “60 mph speeds. Now, about 25 percent of vehicle miles traveled are driven on Interstate and urban highways. That means that just a quarter of traffic is traveling at optimal speeds. Creating a Parkway Grid would allow up to 75 percent of all miles to be driven at 45 “60 mph, without stop-and-go traffic, traffic lights, and congestion. The Even Flow of traffic creates its own savings in terms of energy and cost.

The Parkway Grid takes other savings into account as well:

  • Heavy freight destinations would be placed adjacent to freeways to reduce trucking travel time and low-efficiency miles driven.
  • A bikeway grid adjacent to the parkway could account for up to 20 percent of miles driven within a 10-mile radius. This would reduce the total light-duty-vehicle (LDV) miles traveled.


Parkway City Trip Compared with Other Policy Mitigation Options

Figure 1: Policy Mitigation Option (from Pew Center on Global Climate Change)

Policies like the one above do not envision a transformative approach to mobility; they are not broad enough in scope. As a result, the savings from improved traffic flow are paltry.  But if 50 percent of LDV miles see a boost in efficiency of 25 percent, then a savings of 10 percent results to this sector, which translates into 6 percent of total transportation energy use.  The 1 to 2 percent improvement shown in the Pew chart for traffic flow is just that which is attributable to congestion.

Likewise, trucking reductions would likely be less than 5 percent and contribute less than 1 percent to the total savings. Another point to consider is that trip planning and route efficiency improvements shown in the chart are mostly attributable to information systems and GPS “not the direct routes and walkable grid of the Parkway City. These would certainly achieve the high mitigation figures for an additional 5 percent savings.

Total Even Flow savings of over 10 percent of total transportation costs result even before considering savings from mixed-use synergies, compact development, transit use, and ride-sharing.  Further savings are virtually assured.


Richard Vermeulen - Construction Economist for Green Building

Richard Vermeulen is the construction economist creating profitable sustainability in the built environment. He’s the founder of GreenLight™, author of Green at No Cost, and developer of the Total Benefit Analysis and The Value Process as well as co-CEO, lead economist, and chief estimator for Vermeulens. Richard has developed industry-leading standards for estimating and data-basing complex construction projects throughout North America. In addition to consulting for thousands of major projects over 30 years, Richard has designed and built residential and commercial projects, from hammering nails to hound-dogging bureaucracies. He has traveled extensively, always with an awareness of how cities do and don’t work.

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