What Is Sprawl Development?
Sprawl development is the outward expansion of low-density housing units on the outskirts of cities, far from commercial centers.
Within the Bay Area, sprawl development has threatened to destroy the greenbelt of natural and agricultural lands that surround cities and towns. Learn more about what a greenbelt is here.
What Are the Impacts of Sprawl Development?
Sprawl development impacts cities in many ways ranging from transportation to community development. When a city develops beyond its limits and onto the undeveloped land beyond it, it carries with it unforeseen consequences. Sprawling housing developments cause environmental, financial, social, and psychological effects for residents.
Infrastructure and Costs
Low-density sprawl costs local governments more in the long run than “infill” development, which is the growth within existing urban areas. Sprawling outward requires that new roads, water mains, sewer pipes, and other infrastructure be extended into greenfield areas—undeveloped land outside of cities and towns—while infill development usually requires simply upgrading existing city infrastructure.
Sprawl development is an expensive proposition.
Multiple studies show that sprawl is more expensive than infill growth within cities. A 2015 study found that sprawl costs America over $1 trillion, and can increase per-capita land consumption by up to 80% and car use by up to 60%. Providing water, sewer, roads, and other services to far-flung neighborhoods is very costly for local governments. Smart growth allows more affordable housing types at increased densities, reduces land requirements per household, has lower public service costs, and reduces transportation costs. The higher housing prices that residents may pay will be offset by lower transportation costs, energy costs, and better access to jobs, services, and amenities in more centralized locations.
Transportation costs rise as density decreases.
Residents in sprawl neighborhoods are expected to drive three times as much as urban drivers, who rely more heavily on walking, biking, and public transit. A San Francisco State University study found a 10% increase in compact development and smart growth amenities resulted in a 20% decrease in vehicle miles traveled. In addition, the estimated yearly cost per household to provide roads in the most sprawled communities averaged $804.74 in comparison to $19.87 in the highest density communities.
Sprawl development causes more traffic.
Building or expanding roads to serve new or existing sprawl only increases congestion through “induced demand.” Adding road capacity encourages people to take longer trips or more trips by car. A recent $1 billion infrastructure investment to widen I-405 in Los Angeles resulted in commute times one minute slower than before the widening. This in turn only lengthens driver’s commutes. Drivers with a 30-minute commute will spend on average 87 hours dealing with traffic delays over the course of one year. That’s over 3½ days of sitting in congestion!
Sprawl development is harmful to our health.
Numerous studies have shown how sprawl negatively affects our health. Cities built around car use provide fewer opportunities to exercise than walkable and bikeable cities. Cars and trucks release air pollutants, including ozone, carbon, and airborne particulates, that are harmful to both wildlife and humans. Air pollution is a known cause of some respiratory problems, such as asthma and lung cancer. Studies have linked increased VMT to rising obesity rates, diabetes potential, chronic illness effects, inactivity, and mental health impacts. People living in less walkable communities have a 50% higher rate of diabetes as compared to the most walkable communities. Thirty-five percent of people in walkable neighborhoods are overweight, compared with 60% in sprawl neighborhoods.
Another study found there was a positive correlation between the degree of sprawl and the amount of traffic and pedestrian deaths in the largest 101 U.S. metropolitan areas. For every 1% increase in the study’s density metric, the traffic and pedestrian death rates decreased by 1.49% and 1.47%, respectively.
Sprawl residents pay more for public services.
Sprawl requires more expensive public services than infill development. For example, a new development on the outskirts of a city requires police and fire services. Because this development is more distant, more officers may need to be working at a time to cover the additional area. The further a home is from a fire station, the higher its property insurance rates to address a low fire rating. One study found that a fire station in a low-density neighborhood serves one-quarter of households at four times the cost of an otherwise identical fire station in a more compact neighborhood. Similarly, the costs of municipal services also rise as sprawl increases. Denser communities pay less to provide infrastructure and services including water, roads, solid waste, libraries, parks and recreation, governance, and more. A city’s annual average household cost for public services is $1,416 in high-density areas, and up to a whopping $3,462 in sprawling areas.
Sprawl development uses more water.
As lot sizes increase, water consumption increases largely due to the increased irrigation needs. In San Francisco, the average resident uses just 45.7 gallons of water per day, the lowest in all of California. Smart growth development tends to have less water-consuming landscaping. A 2015 report from Energy Innovation and Calthorpe Associates found annual per-capita water use almost doubled from 25,000 gallons in “urban” development to 44,000 gallons in “standard” (sprawl) development.
An analysis found that if all future housing development was to be done as infill development, it would reduce water consumption by 9%. Denser development also helps reduce water lost to leaky pipes. A 2014 assessment from the American Water Works Association found that California leaks about 228 billion gallons of water per year in underground pipes. This represents 25% of the total water in the system, which is about the annual water demand for the entire city of Los Angeles. Building within our existing cities instead of expanding into open spaces or agricultural lands creates fewer opportunities for leaks simply because fewer miles of pipes will be necessary to serve development.
Preventing Sprawl Development
With extensive studies and reports leading to the conclusion that sprawl has a negative impact, the question remains of why are developers still building sprawl? An article in The Atlantic delves further into this question about the continued use of sprawling development even with substantial evidence against it. And our At Risk: The Bay Area Greenbelt report is is the definitive research on the farms, ranches, and natural areas at risk of being lost forever to sprawl development.
Greenbelt Alliance stops sprawl in the Bay Area. Through continued campaigning for urban growth boundaries and the promotion of infill development to refresh existing downtowns, we became the first Bay Area environmental group to shift the focus to not just preventing bad development, but also encouraging the right development in the right places. Read more about our mission, history, and how we work.
You can help.
Get monthly updates on smart growth and conservation in the Bay Area.