road widths: sharrows vs. bike lanes

[scoot]

This topic came up in the Crystal Drive discussion, but is better suited to a new thread:

For roads with parallel parking and a single general vehicle lane in each direction, how much space is needed for vehicles to safely pass bicycles without crossing the yellow lines? At what width do sharrow markings become preferable to painted bike lanes?

IIUC, a general rule for lane widths is that any single lane less than 14′ too narrow for a bike and a motor vehicle side by side, and riders are thus advised to take the full lane whenever it is less than 14′.
Examples (two-lane): most of the roads through Fort Myer, Lake Barcroft area, etc.
Examples (multi-lane): Columbia Pike, most of S Walter Reed, most of George Mason Drive

But that rule assumes no parked cars. Consider the following configuration: 10′ travel lane, 5′ bike lane, parallel parking. Parked cars will render most of the bike lane useless. Some may venture a bit closer, but I always keep at least 4 feet from parked cars, so I end up riding with wheels on the white line in most door-zone bike lanes (e.g. 34th Street S through Fairlington). However, riding on or near that line invites very close passes from drivers who are afraid to cross the yellow lines.

Seems to me that wherever the right boundary is adjacent to car doors, anything less than about 16′-17′ total should be marked as a sharrows, not a vehicle + bike lane. Thoughts?

Topic

[lordofthemark]

@dasgeh 124555 wrote:

Maybe. Honestly, this is why I’m wishy-washy about this sort of thing. I can’t see spending much energy to fight for it, and of course I’m not going to fight against it if it’s all we got, because I do think painting a picture of a bike on a street is better than nothing.

But the Crystal Drive situation is a good example: If we can convince the County we have a few extra feet, is it better to make the painted southbound bike lane protected and have no north bound bike lane (that will be on Clark/Bell), or is it better to have 2, paint-only bike lanes, one of which is to the right of a transitway, and the other to the left of parking?

I am not sure I know the area well enough to say, but my instinct would be the PBL, with NB on Clark/Bell. Especially as E-W connectivity improves (?) that should leave absolutely needed residual NB movement short enough that those folks unwilling to take the lane NB can be accommodated on the sidewalk (esp when it gets wider – till then they can dismount and walk if necessary)

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