I appreciate any comments, suggestions, and questions.The whole area of lane sharing/splitting can be confusing, particularly in terms of when/where it's legal, safe and appropriate. This writeup attempts to explain the concepts and issues as simply and clearly as possible.
Basic definitions.
Various people use the following terms in various ways, sometimes interchangeably. I've tried to sort it out by what most people mean most of the time.
- Lane-sharing: (or sharing lanes). The practice of traveling far enough over to one side or another of a lane to leave room for the driver of another vehicle to also use part of that same lane (to be overtaken, or to share side-by-side at the same speed), or the practice of using unused space in a lane to overtake slower traffic using another part of that lane. Motorcyclists sometimes share lanes not side-by-side, but in a staggered fashion - one ahead and over laterally from the other. Dozens of bicyclists sometimes share one lane by riding in tight packs behaving like a single unit, similar to a flock of birds.
- Lane-straddling: Operating a vehicle on or near a lane stripe that separates two lanes such that the vehicle is encroaching at least some into both of the adjacent lanes separated by the stripe.
- Lane-splitting: The practice of sharing lanes by riding a bicycle or motorcycle between two lines of traffic. Note that passing a line of congested traffic on the outside is not "lane-splitting", because the cyclist is not between two lines of traffic.
- Whitelining: Using lane-straddling in order to lane-split.
- Controlling the lane: Cycling in a lane position that precludes others (particularly drivers of cars and other 4-wheeled vehicles) from using adjacent space within the same lane at the same time. Commonly referred to as taking the lane. If a cyclist is controlling the lane then he is not lane-sharing (and vice-versa).
- Filtering forward: Using lane-sharing (either on the outside or lane-splitting) to overtake slow or stopped traffic.
Some observations that stem from these definitions:- Lane-splitting comes in two basic varieties:
- Whitelining -- splitting the two lanes at or near the white lane stripe: riding on or near enough to the stripe to be encroaching into both lanes at once;
- Without whitelining -- splitting the two lanes far enough over from the white lane stripe to not be encroaching into the adjacent lane: riding in a lane in the space between the lane stripe and vehicles in the same lane, but not encroaching over the center of the lane stripe into the adjacent lane.
- Lane-sharing without lane-splitting is lane-sharing on the outside (using space to the right of the rightmost lane).
- Curbhugging is extremely generous (to a fault) lane-sharing on the outside. Usually it refers to riding so far to the right that safety is unnecessarily compromised for one reason or another.
- In the context of motorcycling, lane-sharing is almost always used to refer to filtering forward while lane-splitting, so these three terms, along with whitelining, are often used interchangeably in that context. For example:
Often called lane-splitting, white-lining, or filtering, lanesharing is the practice by motorcyclists of moving between stopped or slow moving traffic during times of congestion and between lanes of vehicles, traveling in the same direction.
http://laneshare.org/index.html
Legal issues
Language in laws like California's
CVC 21658 seem to make
lane-splitting illegal, if you read it with
lane-splitting in mind:
- 21658. (a) A vehicle shall be driven as nearly as practical entirely within a single lane and shall not be moved from the lane until such movement can be made with reasonable safety.
However, what this law is clearly intending to prohibit is
lane-straddling by drivers of normal-width vehicles, in order to prevent one driver from occupying two lanes simultaneously. Clearly a
whitelining cyclist cannot do that. If the intent was to prohibit
lane-splitting, then why would they prohibit
lane-splitting of the
whitelining variety, but not
lane-splitting of the
without whitelining variety? Since they are clearly not prohibiting
lane-splitting of the
without whitelining variety, it seems reasonable to assume that there is no intent in 21658 to prohibit any kind of
lane-splitting.
Safety issues
Just because it's legal, doesn't mean it's safe. Both varieties of lane-splitting, as well as lane-sharing on the outside, have various hazards. When traffic is stopped, riding in door zones is always hazardous, on either side. It can be the safe and reasonable thing to do when done carefully. If the reasonable safety of lane-splitting or lane-sharing is in doubt in a given situation, don't do it.
I appreciate any comments, suggestions, and questions.
EDITS:
02/01/08 - Added curbhugging definition per Bek's question.
02/02/08 Changed lane-sharing definition from:
- Lane-sharing: Traveling fully within a lane, but alongside another vehicle in that same lane. The other vehicle may be lane-sharing or lane-straddling.
to:
- Lane-sharing: Traveling fully within a lane, but far enough over to one side or another to leave room for another vehicle to travel alongside in that same lane. When another vehicle is present alongside it may be lane-sharing or lane-straddling, and may be moving faster, slower or at the same speed (traveling alongside another vehicle moving at the same speed is generally considered dangerous, whether it's the same or an adjacent lane).
02/02/08: Added controlling the lane definitions; expanded on curbhugging.
02/04/08: Updated definitions of lane-sharing and lane-splitting; added whitelining and filtering forward, etc. See post #36 for details.
02/05/08: Updated lane-sharing again. See post #40 for details.
02/05/08: Expanded the observation about the varieties of lane-splitting.