Sunday, November 11, 2007

How Wide is a "Share-able" Lane?

Keri from Orlando wrote:

Where do you ride if you are in a lane that is just wide enough for a car to squeeze past you within the lane when you ride ~3 feet from the curb? I'm struggling with this one. I don't want them to squeeze past me within the lane. I don't want to ride closer to the curb. Would this lane width be less than 14 feet?

The two key questions here are "How wide must a lane be to be "share-able?" and "How far from the curb/edge should I be if it is?"

Many states have statutes allowing bicyclists to leave the right-hand side of the lane if the lane is too narrow to share with another vehicle, but none of them define just how wide such a lane would be. The Florida Department of Transportation actually did define that in their standards: 14 feet. But that doesn't officially (statutorily) define a 14-foot lane as wide enough to share. Still, I think it's a reasonable width; it's based on cyclist needs, safe passing, standard vehicle widths, and sound reasoning.


















Of course you're not going to stop and pull out a tape measure to figure out if the lane is wide enough to share. Instead, just look at a car ahead of you in the lane and ask yourself if there is enough width left over from the vehicle for you to operate safely. If the answer is No, then move left into the lane.


















Keri doesn't want to ride "less than 3 feet from the curb," but lane widths are measured from the lane stripe to the edge of the pavement, not to the curb, so a 14-foot lane would be 15.5 feet if measured to the curb face. On most modern streets in Florida, the gutterpan is about 18 inches wide, so if you ride about 18 inches left from the seam of the asphalt and the gutterpan you'll be about 3 feet from the curb face.


















Moving inward from the curb face: 18 inches of gutterpan + 18 inches to the cyclist's wheeltrack + 18-24 inches to the left shoulder of the cyclist + 3 feet of safe passing space = 7.5 to 8 feet. That would leave 8 to 8.5 feet of space for the passing motor vehicle. Standard-size cars are about 5.5 feet; full-size SUVs and vans about 7 feet; large trucks and buses 8.5 feet.

I think 18 inches is sufficient distance to ride from the gutterpan seam, usually giving you enough maneuvering room to deal with debris and crosswinds. Potholes are another matter.

If the lane is less than 14 feet, you're justified in moving farther left. Unfortunately, most motorists don't see it that way. They usually see a 12-foot lane as wide enough to share.

8 comments:

Donald said...

Good analysis, but I have to say I disagree with your final comments. Most motorists don't see a lane as share-able at all and believe that bicycles don't have a right to use the road in the first place. Even when there is a bike lane. >_<

Keri said...

Thanks Mighk! Great explanation. The illustrations are very helpful too.

Regardless of whether or not they WANT to share it, a higher percentage of motorists recognize that a 9 or 10 foot lane is not share-able because they can visualize it. I find that most motorists pass safely without comment when I take a narrow lane.

As Mighk says, that perception does change as the lane width increases. A lot of roads seem to have that ambiguous width that motorists visualize as share-able, but would be unsafe or uncomfortable for us to share.

It's helpful to recognize that we do have a right to take that lane! To borrow from a recent FBA blog post (http://flabicycle.blogspot.com/) “I'm good enough, I'm smart enough, and doggone it, I deserve to be passed safely!”

:-)

Anonymous said...

Interesting post you got here. I'd like to read more about this topic.
BTW check the design I've made myself London escort

Anonymous said...

Cool story you place here.
It will be useful to find something more concerning this post.
Thx you for give that information.
With best regards Mila!
kiev escort ladies

Kiev escort models said...

I am very enjoyed for this site. Its an informative topic. It help me very much to solve some problems. Its opportunity are so fantastic and working style so speedy. I think it may be help all of you. Thanks a lot for enjoying this beauty article with me. I am appreciating it very much! Looking forward to another great article. Good luck to the author! all the best!

Send Eid gifts to Pakistan said...

I suggest this site to my friends so it could be useful & informative for them also Great effort.

digital camera battery said...

Invest in discharge MaxiDAS DS708 x431 diagun, lexia gm tech 2 A variety MB Star C3 of et cetera Multi-cardiag M8 such motor VAS 5054A vehicle Launch X431 Diagun analysis software on the web may perhaps lexia 3 pp2000 commonly ck 100 help you feel VOLVO Vida Dice ambivalent, the good Nissan Consult 3 reason you are trying to get it online is made for match up against the genuine store's fee the expense of website a lot beautiful. Yet any fault is that we won't look at realistic commodities

==========

Underneath is really a Cummins inline 5 suggestions about several carprog v4.1 car analysis product T300 renault will SBB Key Programmer movie, Renault Could AutoBoss V30 certainly Tacho Pro 2008 Show: v114is a Autocom CDP detailed analytical Fcar F3-G system for the purpose of Renault autos. Renault Can Clip's navigation maxidiag md802 makes it possible nexiq 125032 for discovering all the information concerning the automobile, Laptop computer examination, Intelligent test out however computer systems, Reprogramming, Airbag test out, Diagnostic scan tool (OBD testing), Platform Doctor (admission to Technological Notices), Bricks-and-mortar data.



High School Diploma Program said...

great work has been done thanks for sharing and keep it up