While many four-to-three lane reconfigurations have been used successfully around the country, others have been piloted and subsequently removed. The North Avenue Pilot is taking the proven road design principles and lessons learned from these projects, many of which are similar to North Avenue in terms of traffic volume and road configuration. 4-to-3 lane conversions are generally recommended for roads that have volumes of fewer than 20,000 vehicles/day. North Avenue has 13,900 – 19,100 vehicles per day.

Here are a few examples of successful projects:

Burlington, VT – Colchester Ave.

Colchester Ave in front of the hospital used to be a 4 lane road carrying 18,000 vehicles per day.. Since the 4-3 lane conversion, reports indicate:

  • There has been no reported change in traffic volumes along Colchester Ave. after the restriping.
  • Max queues in the AM peak periods have remained the same and even decreased at some approaches (optimizing signal timing was a part of this project).
  • PM peak queues decreased at several approaches in the corridor including NB traffic on Prospect, EB traffic on Colchester, and NB traffic on East Ave.
  • There has been an increase in cycling on Colchester Ave. after the installation of new bike facilities.
  • Traffic flow has become more uniform.  No significant decrease in travel speed has been observed after the restriping, but there has been an overall increase in pace of traffic through the corridor.
  • Crash data has not been evaluated yet for a comparable length of time.
  • Public input included 274 comments (emails and phone calls) of which 83% were positive, 12% negative, and 5% neutral.
  • Public concerns with the 3-lane configuration included more congestion and delays in some areas, confusion in the center turn lane, poor drainage, and narrow bike lanes.

Madison, WI – Sherman Ave.

A local Burlington resident recently relocated from Madison and had this to say about the project. “We moved to the New North End in August from Madison, WI where a nearby 4-lane street, with 17,000 cars/day, was changed to a 3-lane with bike lanes. The result was overall positive, and dramatically better in the area of safety.”


  1. Car-bicycle accidents dropped to zero.
  2. Overall accidents dropped dramatically.
  3. Traffic slowed a tad, but was still over the posted limit.
  4. Volume varied, up in places, down in others, but did not push it onto side residential streets.
  5. Bicycle traffic increased significantly.
  6. Bicyclers and pedestrians felt safer using the street.
  7. Drivers found it safer and easier to maneuver, around buses or turning traffic.
  8. The change did not negatively affect business income or traffic. Opposition has disappeared.
  9. A three-lane street is significantly safer than four lanes, especially with bicycles.
  10. The city’s conclusion was that the change was positive, and would be permanent.

Source: https://www.cityofmadison.com/council/district/districtfiles/district12/documents/ShermanAveReport.pdf

San Francisco – Valencia St.

“Before the Valencia Street project was implemented, the community was split between excitement and fear of what might result,” says Michael Sallaberry, transportation engineer for  the San Francisco Municipal Transportation Agency. “After it was implemented, it was embraced by nearly everyone as a success — not only by people who ride bikes, but those who walk, businesses along the street and the neighborhood in general.”


  • 20% reduction in crashes
  • 36% reduction in pedestrian collisions
  • 140% increase in cycling

Source: http://www.westerncity.com/Western-City/February-2015/Road-Diets-Make-Streets-Leaner-Safer-and-More-Efficient/

Seattle, WA – Multiple streets

These projects bring about safer streets without affecting traffic volumes”


  • Significant reduction in aggressive speeding (drivers traveling at least 10 miles per hour over the speed limit)
  • Injury collisions reduced between 17% and 75%

Source: http://walkinginseattle.org/?tag=road-diet

Other projects

Cumberland County, Pennsylvania

Barre-Montpelier Road

Here are a few examples of 4-3 lane pilots that resulted in a final 4-lane configuration:

Rutland, VT – Woodstock Avenue

The Rutland, VT road diet did not include any quantative assessment. The Board of Highway Commissioners expected the project to slow traffic and increase safety, but found it created a new set of difficulties and hazards on the road. Source: Rutland Herald Article

Boulder CO – Living Lab Program

The City of Boulder’s Living Lab program tests innovative facilities to improve travel safety, promote travel options, and determine how people feel when using them. The Folsom Street pilot project included a 4-3 lane conversion and qualitative and quantitative analysis. Ultimately Folsom Street was restored to four vehicle lanes.

During the 5-weeks of pilot installation, quantitative measurements showed:

  • Vehicle volumes and speeds were reduced by an average of 15% and 7% respectively
  • Bicycle volumes increased by 51%
  • Average PM peak vehicle travel time increased generally as predicted in the traffic model
  • Public feedback during the first month was 40% negative, 57% positive, and 2% neutral, however the volume of feedback was much greater than anticipated.
  • The Folsom Street project, in the context of all other Living Lab projects and other major private and public construction projects, made traveling through Boulder temporarily more challenging. Staff recognized a lack of sensitivity about this potential for frustration related to traffic disruptions.

Source: https://documents.bouldercolorado.gov/weblink8/0/doc/130441/Electronic.aspx