Is Your Community Following National Guidelines When Installing Bicycle Lanes?

The U.S. Department of Transportation Federal Highway Administration (FHWA) and the National Association of City Transportation Officials (NACTO) both provide guidelines for communities to use when determining the appropriate type of bike lane on streets and roadways. Both agencies recommend that separated or protected bike lanes be used for roads at much lower speeds than are seen in most Arizona communities.

Urban Roadways


The FWHA Bikeway Selection Guide (a page from which is displayed at right) shows that urban roadways with motor vehicle speeds at 35 miles per hour or higher should have separated bike lanes without regard for the number of motor vehicles using the roadway.

The FWHA guide indicates that if the actual motor vehicle speed is higher than the posted speed limit, the actual speed should be used for the bikeway selection.

The NACTO guidance, Designing for All Ages & Abilities: Contextual Guidance for High-Comfort Bicycle Facilities, (a page of which is shown below) recommends that any roadway with a speed greater than 26 mph and more than 6,000 motor vehicles per day should have a protected bike lane. On roadways with less than 6,000 motor vehicle trips per day they recommend that a protected bike lane be installed unless the community chooses to reduce the speed limit and/or reduce the number of motor vehicle traffic lanes.



The FHWA Bikeway Selection Guide indicates that on a narrow street where motor vehicle traffic is less than 3000 vehicles per day, a community can apply for an exception to conduct an experiment using an advisory bike lane; described as follows.

Advisory bike lanes demarcate a preferred space for bicyclists and motorists to operate on narrow streets that would otherwise be shared lanes. Unlike dedicated bicycle lanes, motor vehicle use is not prohibited in the advisory bike lane and is expected on occasion.

This diagram, from the City of Alexandria, VA, shows the expected use of the advisory bike lane.

Research on advisory bike lanes conducted in Ottawa, Canada, found that motor vehicle speeds decreased, and bicycle rider speeds increased on roadways with this design. But their research did not indicate any impact on collisions between motor vehicles and people on bicycles. The article is available at

It is difficult to visualize this type of traffic lane design used at speeds (up to 35 MPH) that FHWA might allow for this type of experiment. NACTO states that “most people are not comfortable riding a bicycle immediately next to a motor vehicle driving at speeds over 25 mph” and this design could require people on bicycles to share lanes with motorists traveling at speeds higher than that.

Rural Roadways

On rural roadways, the FHWA recommends shoulder width based on the motor vehicle volume and speed. As shown below, the minimum shoulder width for a roadway with more than 1000 motor vehicles per day is 5 feet; this should be expanded up to 10 feet for higher speeds and traffic volumes.

This creates the expectation that the bicycle rider will ride on this shoulder, so the shoulder would need to be clean and smooth for bicycle riding. This conflicts with Arizona Statute 28-601 which states that the shoulder is not considered part of the roadway. In a 2022 Sierra Vista court decision, it was determined that a bicycle rider was riding on the shoulder when injured and therefore did not have an expectation of a safe riding surface.

The FHWA guidance also recommends shared use paths along rural roads

  • with higher speeds (45 mph or greater)
  • with locations that attract larger volumes of bicyclists due to scenic views
  • for routes that serve as key bicycle connections between destinations
  • for routes where families and children make connections in rural areas
  • on rural roads with Average Daily Traffic above 6000 motor vehicles per day


Bicycle Lanes are a Proven Safety Countermeasure

The addition of bicycle lanes is a FHWA proven safety countermeasure and have been shown to reduce crashes.

How to Use This Information

If you are involved in your community’s bicycle facility projects, work to include these recommendations into the bicycle lane selection process. If you are not currently working with anyone, check with your community to see what guidelines they are using when selecting and installing bike lanes. If they are not using these guidelines, suggest that they incorporate them as the develop new roadways and refurbish existing roadways.






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