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Bicycle Lanes width

  • 1.  Bicycle Lanes width

    Posted 09-20-2018 04:57 PM
    Edited by Tirza Austin 09-20-2018 04:57 PM
    Hello everyone,

    I am currently doing the design for a city, where we will be doing some re-striping job on roads where the city has jurisdiction. For this reason, we are following the AASHTO - Guide for the Development of Bicycle Facilities, 2012, where it says a minimum width of 4ft for bicycle lanes. 
    However, TxDOT is supervising the entire job, and TxDOT has a 5ft minimum width for bicycle lanes guideline.

    Should we follow the TxDOT guidelines with the 5ft, or since we are only working with local roads is the 4ft acceptable?


    Pedro Zavagna A.M.ASCE

  • 2.  RE: Bicycle Lanes width

    Posted 09-20-2018 06:18 PM
    Edited by Tirza Austin 09-20-2018 06:18 PM
    Hi Pedro,

    When you say TxDOT is supervising, what exactly is their scope on this project?

    Ameer Mufleh
    West Palm Beach FL

  • 3.  RE: Bicycle Lanes width

    Posted 09-21-2018 10:46 AM
    TxDOT is responsible for doing all the striping job.

    Pedro Zavagna EIT, A.M.ASCE
    Tyler TX

  • 4.  RE: Bicycle Lanes width

    Posted 09-21-2018 07:26 AM
    Edited by Tirza Austin 09-21-2018 07:26 AM
    Who owns and maintains the facility after it is built?  Is the state paying for any of the path?  Here in WI we have built local paths to city requirements in state projects because the city will ultimately own and maintain the facility.

    William Mohr P.E., M.ASCE
    State Of Wisconsin
    Greenfield WI
    (262) 548-5666

  • 5.  RE: Bicycle Lanes width

    Posted 09-21-2018 10:46 AM
    Edited by Tirza Austin 09-21-2018 10:46 AM
    The city owns and will be the one responsible for maintaining all the roads after the striping job is finished.

    Pedro Zavagna EIT, A.M.ASCE
    Tyler TX

  • 6.  RE: Bicycle Lanes width

    Posted 09-21-2018 10:49 AM
    Edited by Tirza Austin 09-21-2018 10:48 AM
    Four feet is good enough according to AASHTO. 5 feet may increase cost. 

    Ejaz Khan S.M.ASCE
    Pakhtunkhawa Highways Authority

  • 7.  RE: Bicycle Lanes width
    Best Answer

    Posted 09-21-2018 02:20 PM
    Edited by Pedro Zavagna 10-30-2018 01:10 PM
    Since the AASHTO standard is a MINIMUM, and since TXDoT is doing the project, and since the project only involves striping, not pavement construction, and since a wider facility is more comfortable for more users, I'd say use the 5' standard where the existing roadway width allows, and use 4' only where the pavement is narrowed.

    Kristofer Singleton P.E., M.ASCE
    Project Manager
    Howard County DPW
    Columbia MD

  • 8.  RE: Bicycle Lanes width

    Posted 09-22-2018 10:57 AM
    Edited by Tirza Austin 09-22-2018 10:57 AM
    PennDOT also calls for 5' bike lanes.  But, more importantly, the lane width needs to take into consideration the volume of vehicular and bike traffic, width of the traveled way, and the posted speed limit,  Narrowing the vehicle lanes should have the effect of traffic calming.

    Gerald] [Maragos] [PE - MASCE
    Sr. Project Engineer - Retired
    New Cumberland, PA


  • 9.  RE: Bicycle Lanes width

    Posted 09-22-2018 11:02 AM
    Edited by Tirza Austin 09-22-2018 11:01 AM
    I agree with Mr. Singleton and would go further.  AASHTO publications are a guide and not the standard unless adopted.  FHWA has adopted them for National Highways or federally funded work but defers to state or local standards that are properly adopted and are of equal or greater than the AASHTO standard.  AASHTO may recommend 4 fee but the city (presuming this was a properly adopted standard) requires 5-foot wide bike lanes.  The design should install the wider lane unless the city allows otherwise.

    Robert Effinger P.E., M.ASCE
    Project Delivery Coordinator
    California Department of Transportation

  • 10.  RE: Bicycle Lanes width

    Posted 10-30-2018 01:14 PM
    Edited by Tirza Austin 10-30-2018 01:14 PM
    Thanks Kristopher,
    Your answer was the best one. We talked with TxDOT and the city engineer, and decided to make a few changes into the city master plan. With those changes, we can use the 4ft minimum if we have 1ft from the gutter to the face of curb, decreasing the vehicle lanes to 9ft, 10ft or 11ft if required. We also adopted 5ft bicycle lanes on situations where the vehicle lane was more than 11ft.

    Thanks for your help

    Pedro Zavagna EIT, A.M.ASCE
    Tyler TX

  • 11.  RE: Bicycle Lanes width

    Posted 10-31-2018 10:08 AM
    Edited by Tirza Austin 10-31-2018 10:07 AM
    ​Kristopher is right.
    We are licensed to protect the public.
    The criterion is what is safest for the public, not which guideline or standard to use.  We're licensed to apply our professional judgment.
    If the bike lane is 5', does that make the vehicle way narrower?  If so, what are the consequences?  Drivers have less 'crash avoidance room?'  Is it a minor road with low ADT?  Is it in a neighborhood with drivers easily distracted?
    Standards and regulations give minimums and maximums, but they're not the basis for design.

    Karl Sieg P.E., M.ASCE
    Sieg & Associates Inc
    Wexford PA
    (724) 935-2040

  • 12.  RE: Bicycle Lanes width

    Posted 10-31-2018 08:12 AM
    Edited by Tirza Austin 10-31-2018 08:12 AM

    I would also like to clarify the interpretation of the 4-foot minimum width included in the AASHTO Bike Guide. (Our firm collaborated with AASHTO to write the 2012 guide and is currently working on an update.) The 4-foot dimension is based on the minimum operating space needed by the cyclist and is intended to exclude the gutter pan. This is because the seam between the pavement and the gutter can represent a crash hazard for cyclists. If the curb and gutter are TXDOT standard with a vertical curb, then the distance from the face of curb should actually be 5 feet, 4 inches if possible. A 4-foot width that includes the gutter pan should only be used in "extremely constrained" low-speed roadways (< 45 mph) when no gutter is present (see section 4-13 of the Bike Guide), and should only be used over short distances.

    Providing 4 feet outside of the gutter pan also allows the cyclist room to navigate around things like drainage structures. TXDOT standard curb inlets are of particular concern, since the depression in the gutter pan at the curb opening is 4 inches. That is a pretty significant discontinuity in the surface of the bike lane, and also represents a crash hazard for the cyclist. If any of the inlets include grates, then the grates should be replaced with bicycle safe grates prior to adding bike lanes.

    If your project includes areas where there is on-street parking, the Bike Guide also recommends a 6-foot width where the bike lane is adjacent to parking. The 6-foot dimension allows additional operating space for cyclists to avoid vehicle doors that may be opened without warning or vehicles that may be maneuvering in and out of perpendicular or diagonal spaces along the roadway. "Dooring" is most common in downtown areas where parking turnover is high, but the potential should be considered anywhere a bike lane is adjacent to parking. If you have the luxury of additional pavement beyond what is needed for the vehicular travel lanes and bike lanes, additional buffering should be considered. Vehicle doors usually extend about 3 feet when opened, so providing a 3-foot buffer or separation between parking and bike lanes is desirable.

    Melany Alliston-Brick, P.E., M.ASCE
    Civil Engineering Practice Director, North America
    Toole Design Group, LLC
    Silver Spring, MD
    (571) 830-4272

  • 13.  RE: Bicycle Lanes width

    Posted 02-13-2019 10:01 AM
    Edited by Tirza Austin 02-13-2019 10:01 AM

    Is there a target date for the release of the revised guide?

    Thank you!

    Monty Karns PE,MASCE
    Stillwater OK

  • 14.  RE: Bicycle Lanes width

    Posted 01-08-2019 02:48 PM
    Edited by Tirza Austin 01-08-2019 02:48 PM
    Everyone on this thread may be interested in the ASCE plot points episode 6 which just came out today and is all about bicycle travel. While this doesn't directly answer the original question, I found the discussion of design philosophies for bicycle lanes, as well as the upcoming AASHTO updates, fascinating and relevant to this thread.

    Click HERE to listen to the podcast.

    Stephanie Slocum P.E., M.ASCE
    Engineers Rising LLC

  • 15.  RE: Bicycle Lanes width

    Posted 02-12-2019 05:09 PM
    Edited by Tirza Austin 02-12-2019 05:09 PM
    Are there any laws, ordinances or other legal restrictions ergardoing bicycles?  If so, follow them.   As already mentioned the rest of the published literature contains guidelines, suggestions, and "expert" recommendations.  Local road/street conditions vary so much that a set of circumstances suggested by the author of any text may not exist at all for the design location.  For instance, a 9 ft lane for autos and a 4 ft lane for bikes?  Sounds more like a shared lane condition.  But what about road speed, pedestrians, and so many other things facing the motorist/bicycle passage?  Want to figure out the best thing for a particular location?  Get on a bike and ride, ride, ride.  Talk to a local riding club.  Talk to both on-road cyclists and rails-to-trails riders.  Talk to local bicycle commuters. And so on.  They have the experience of what a cyclist faces and what motorists will do in a crowded roadway situation.  No textbook has the same feel as a seat and a set of handlebars when riding a bicycle.

    Norman Voigt PE,LS,FASCE
    Pittsburgh PA