Header photo credit: NYC DOT
In January, NACTO published the third edition of Urban Bikeway Design Guide, its first update in a decade. The new edition goes beyond a kit of parts to a more complete how-to manual for designing safe, bikeable, inviting streets. Soon, we’ll make the Urban Bikeway Design Guide available for free on our website. In the meantime, we’re posting excerpts each week here on our blog. Can’t wait until the Guide is on our website? Buy it from Island Press, and use code UBDG3 for 20% off.
Today’s excerpt is from Section 3.3: Protected Bike Lanes.
Protected bike lanes, also known as separated bike lanes, provide a comfortable bike facility for people of all ages and abilities on all types of streets. They are proven tools for safer streets and are essential to every city’s bike network.
Protected bike lanes are separated from general-purpose travel lanes with both a buffer and a vertical element, such as a median, curb, or flexible delineators. Converting an existing constrained bike lane to a protected bike lane can be expected to reduce motor vehicle-bike crashes by over 50%. A decade-long look at protected bike lanes in a dozen U.S. cities found that all street users–people in cars, people walking, people biking–experience safety benefits from protected bike lanes. Protected bike lanes can decrease risk by 90% when compared to a major street with no cycling infrastructure.
Protected bike lanes are appropriate for all streets, in all contexts. Protected bike lanes should be explored for all streets with daily traffic volumes over 6,000, where speeds are more than 25 mph (40 km/h), or where more than one travel lane is present in each direction.
Designing for All Ages & Abilities
When designed, constructed, and maintained well, protected bike lanes provide All Ages & Abilities safety and comfort regardless of vehicular traffic and speeds. Protected bike lanes are the only tool for All Ages & Abilities biking on streets with high curbside demand, speeds of more than 25 mph (40 km/h), multiple adjacent travel lanes, or motor vehicle volumes above 6,000 vehicles per day.
Dimensions
Protected bike lanes always include both a bike lane and a buffer to the street. Protected bike lanes should accommodate comfortable side-by-side bike riding, platooning, or passing using the bike lane and a portion of the buffer.
Protected bike lanes will attract more users because of their high comfort level. On streets without protected bike lanes, the existing bike volumes do not reflect potential demand. Design for the future, considering the existing and potential land use and transportation needs along the bikeway. Protected bike lanes designed to current volumes will likely reach capacity in the near future.
Design protected bike lanes with enough rideable width for all expected users to operate comfortably, ride side-by-side, or pass one another. Rideable width is the usable width of a bikeway for riding, excluding any shy distance, gutter pans, or other unrideable areas. Rideable width can extend beyond the marked bikeway to include parts of the buffer at the same level as the bikeway.
The minimum rideable width for one-way protected bike lanes is 6.5-7 ft (2-2.1 m) and the preferred width for one-way protected bike lanes is 8-12.5 ft (2.5-3.8).
Appropriate buffer widths vary widely, depending on the means of vertical separation, adjacent travel lane speeds, and right-of-way widths. Ensure proper shy distance is provided from all types of vertical separation within the buffer area. Shy distance should not extend into the bike lane.
Parking-protected bike lanes must have a 3 ft (0.9 m) buffer to accommodate the full swing of a car door and mitigate the potential for injurious crashes, commonly known as “doorings.”
In many cities, the rideable width also accommodates maintenance vehicles necessary for sweeping, snow plowing, and snow removal. Maintenance vehicles designed to sweep or clear snow range in widths from 4 ft (1.2m) to over 8 ft (2.4 m). Cities relying on these vehicles for maintenance needs typically have a minimum clear distance of 7-8ft (2.1-2.4 m) on protected bike lanes.
Motor vehicle lanes should be narrowed to support the widest feasible bike lanes. At posted speeds of 35 mph (60 km/h) or less, general-purpose travel lanes can be 10 ft (3 m) wide and still support transit and truck uses. Where transit or heavy trucks are rare, a travel lane of 9 ft (2.7 m) is an acceptable width for general-purpose travel lanes.
Consider allowing emergency vehicles, such as ambulances, to drive in wide protected bike lanes rather than maintaining wide vehicular travel lanes. Design the vertical means of separation to dissuade most drivers while still being semi-permeable to emergency vehicles.
Parking lane widths should be minimized, typically to 7 ft (2.1m), in favor of increased rideable width.
Adapted from Urban Bikeway Design Guide, Third Edition, published by Island Press
