National Complete Streets Coalition

Ease Congestion

Incomplete streets breed congestion

Designing streets only for automobiles reduces opportunities for safe travel choices that can ease traffic congestion: walking, bicycling, and taking public transportation. Americans drove almost three trillion miles in 2008, and many of those trips were very short. Half of all trips are three miles or less and 28% are one mile or less. In rural areas, 30% of all trips are two miles or less, and yet a vast majority of these trips are by automobile. Congestion is not solely an urban issue. Regions of all sizes have experienced increased congestion, costing the economy $87.2 billion in hours lost to traffic jams and wasted fuel in 2007 alone. An evaluation of auto-dependent transportation systems found that their per-capita congestion costs are significantly higher than systems that provide alternatives to driving.

Continuing to invest in incomplete streets will prevent people from using options such as walking, bicycling, or hopping on a bus or train. Networks of Complete Streets, with pedestrian and bicycle infrastructure and improved access to and efficiency of public transportation, are needed in our communities to reduce the burden of congestion on our roadways and improve travel times for all users, regardless of whether they walk, bike, drive, or take public transportation.

Complete streets ease congestion

In response to increasing walking and bicycling across Burrard Bridge, a main connection to downtown, the City of Vancouver, BC transformed a southbound auto-only lane into a southbound bike-only lane on a trial basis. Pedestrians travel on the adjacent sidewalk, while the opposite sidewalk is reserved for bicycle riders heading northbound. The trial has increased bridge capacity: the number of pedestrians and vehicles moving across the bridge has remained constant, while the summer months brought 26% more bicyclists – an additional 70,000 trips. A public opinion survey of Vancouver residents conducted in September 2009 found strong broad support for making the reconfiguration permanent. The success of the trial means the city will not have to spend an extra $30 million to retrofit the bridge for better pedestrian and bicyclist accommodation.

Decades of investment in expanding automobile capacity have not succeeded in keeping congestion in check in the United States. Sixty to seventy percent of increased road capacity (additional lane-miles) on state highways in California counties was filled with new automobile traffic within just five years; at the municipal level, 90% was filled over the same period. Communities are now looking for new ways to meet their residents’ travel needs, and help residents avoid getting stuck in congested traffic conditions. A comprehensive, Complete Streets approach to transportation planning and design will increase transportation choices and encourage efficient use of current roadways by offering alternatives to the automobile, especially during peak travel times.

Providing travel choices – walking, bicycling, and public transportation – can reduce the demand for peak-hour travel in cars, the principal cause of daily congestion. About 44% of all vehicle trips in both congested areas and other areas made during the morning peak are not to work or related to a work trip. Instead, they are for shopping, going to school or the gym, or running errands. Many such trips are short and could be made by walking, bicycling, or taking transit – if the streets are complete. Parents cite traffic as a primary reason for driving children to school, yet in doing so, they account for 7 to 11% of non-commuting vehicle traffic during morning rush hour.

In Boulder, Colorado, twenty years of consistent investment in a multimodal system and a network of Complete Streets has not only kept VMT from growing, but has resulted in huge increases in the share of people walking, bicycling, and taking public transportation. Since 1990, use of single-occupancy vehicles in work commutes has declined 13.9%. Additionally, the number of people walking to work is three times the national average, transit use is twice the national average, and the bicycle commuting share is eighteen times the national average.

Currently, short bicycling and walking trips account for 23 billion miles traveled annually. Shifting even a small portion of travelers out of single occupancy vehicles can have a big effect on congestion. In 2008, when national vehicle miles traveled (VMT) dropped by 3.6% , congestion plunged 30% in the nation’s 100 most congested areas. Combined with the benefits of public transportation access and mixed-use development, modest increases in walking and bicycling could avoid 69 billion miles driven; more substantial increases in travel by walking and bicycling could avoid nearly 200 billion miles driven. Avoiding these miles driven is a much more cost-effective option than continued expansion of highway infrastructure capacity.

Increase road capacity

Planning and designing roads to make them safer for all users and more inviting to pedestrians, bicyclists, and transit users can increase overall capacity and efficiency without a negative impact on automobile travel. For example, improving intersections for pedestrian safety can reduce the time needed for a pedestrian crossing signal phase, keeping vehicular traffic flowing.

A road diet on San Francisco’s Valencia Street reduced automobile through lanes from four to two, adding a center turn lane and two bike lanes. Following this change, collisions involving pedestrians declined 36%, accompanied by an increase in pedestrian traffic and a whopping 140% increase in bicycle riders – all without significantly altering automobile traffic capacity.

Paying attention to all modes in street planning can also create a more efficient system that responds better to travel demand. As the accompanying photographs show, Complete Streets can move more people while using less space. Public transportation is key to mitigating congestion because it carries more people in the same road space. Getting more productivity out of the existing road and public transportation systems is vital to reducing congestion. Complete streets improve access to public transportation and assist transit vehicles in moving efficiently along the road, making it an attractive and viable option to more people. Increasingly popular are the use of bus rapid transit and bus priority signal systems, which allow buses to extend green lights and shorten red lights.


[all fact sheet citations are available in the downloadable files]

Additional Resources:

Driven Apart: How Sprawl is Lengthening Our Commutes and Why Misleading Mobility Measures are Making Things Worse
CEOs for Cities, 2010

Smart Congestion Reductions: Reevaluating the Role Of Highway Expansion For Improving Urban Transportation (.pdf)
Todd Litman, Victoria Transport Policy Institute, 2010

Future of Transportation National Survey 2010
Transportation for America

2009 Annual Urban Mobility Report
David Schrank and Tim Lomax, Texas Transportation Institute, 2009

Active Transportation for America
Rails-to-Trails Conservancy, 2008

Traffic Volume Trends
Federal Highway Administration, 2008

INRIX National Traffic Scorecard Reveals Startling 30 Percent Decrease in Traffic Congestion in 2008
INRIX, 2008

Burrard Bridge Lane Reallocation study, City of Vancouver, British Columbia, Canada
City of Vancouver

NHTS Brief: Congestion: Who is Traveling in the Peak? (.pdf)
US Department of Transportation, 2007

Modal Shift in the Boulder Valley 1990-2006 (.pdf)
National Research Center Inc. for the City of Boulder, Colorado, 2007

Valencia Street Road Diet – Creating Space for Cyclists
Mike Sallaberry, San Francisco Department of Parking and Traffic, 2001

Road Supply and Traffic in California Urban Areas (.pdf)
Mark Hansen and Yuanlin Huang, 1997

  • Sign up for eNews
  • Join the Coalition
  • Donate Today
  • Schedule a Workshop