Three-foot Law


Rodney asked:  Does the three-foot minimum passing statute apply to motorists if a cyclist is operating in a designated bicycle lane?

If not, wouldn’t it be more prudent to forgo the use of the bicycle lane with regards to unsafe speed differentials and passing clearances between the cyclist and motorist?


In the applicable statute, there is no reference to the use of bike lanes or any other lane considerations.  A motorist is required to safely pass a bicyclists no closer than three feet, wherever they may be.  See Bicycles May Use Full Lane.

There are many who believe, with some supporting evidence, that motorists pass bicyclists more closely when they are in a bicycle lane.  I am not aware of any formal studies that provide definitive evidence one way or the other.

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3 comments on “Three-foot Law
  1. keri says:

    The study critiqued here did not intend to prove that, but it kinda did.

    One of the studies in this paper suggests that as well.

    The study referenced in this article from the UK found that bicyclists are passed closer in bike lanes.

    And I have several hours of video that show undeniably closer passing when in a bike lane vs claiming a 10-12ft general travel lane.

  2. danc says:

    Dear Geo regarding “motorists pass bicyclists more closely when they are in a bicycle lane” Paul Schimek, blog posting Bike Lanes for Jamaica Plain? gets to this point.

    “Motorists will leave more room when overtaking bicyclists. When there is a dividing line, motorists assume it is sufficient to stay to the left of the line, whereas when overtaking in the same lane they leave as much room as possible, including using the left half of the road when necessary. (A greater average passing distance without bike lanes was documented in Evaluation of Shared-Use Facilities for Bicycles and Motor Vehicles, Transportation Research Record No. 1578, pages 111-118; William W. Hunter, John R. Feaganes, Raghavan Srinivasan, Conversions of Wide Curb Lanes: The Effect on Bicycle and Motor Vehicle Interactions. Transportation Research Record. Volume 1939 / 2005 Parkin J, Meyers C. The effect of cycle lanes on the proximity between motor traffic and cycle traffic. Accid Anal Prev. 2010 Jan;42(1):159-65. The last study concludes, “The results suggest that in the presence of a cycle lane, drivers may be driving within the confines of their own marked lane with less recognition being given to the need to provide a comfortable passing distance to cycle traffic in the adjacent cycle lane.”)

  3. Geo says:

    That’s good info. Thanks.

2 Pings/Trackbacks for "Three-foot Law"
  1. […] drivers, whether they travel by bicycle or car. Currently, it focuses on educating people on ‘the 3foot law‘ and cyclists’ rights to the road. SFBC members and people who bicycle, well, […]

  2. […] or otherwise physically threaten people on bicycles. This law takes the idea behind the ‘3-foot law‘ further, punishing “drivers who intimidate cyclists with threats, crowding or throwing […]

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