[Tagging] Tagging u-turn restriction with continuous painted line

Kytömaa Lauri lauri.kytomaa at aalto.fi
Thu Jul 5 06:04:47 BST 2012

Pieren wrote:
>but the wiki doesn't say explicitely that "overtaking=no" means "no
>u-turn" as well. Could we write this assertion ?

Probably not.

Here they leave a small (about 3 meter long) gap
in the solid line whenever there's a tiny one lane 
side road (or a driveway) and it's not necessary 
to ban turning left onto said driveway or similar.
An u-turn would be likewise allowed at that spot.
Even if I'm known for going - as some would say -
overkill by splitting ways to short bits for some 
changing road attributes, I don't think it's 
reasonable to have a three meter long way-bit on 
both sides of an intersection just to make sure that
routers don't think they can't turn left (or u-turn) 
there. And to be exact, in most countries overtaking
in the opposite direction lanes is forbidden within an 
intersection, even when the solid line doesn't
continue through the intersection.

An overtaking restriction can be (shouldn't, but can) 
given with just a traffic sign. I'll need to see if I 
(or anybody else) can find a spot where a multilane 
(3+ lanes) undivided road has a no overtaking sign
in the direction with several lanes, but doesn't have
a solid or double solid line in the middle.

Since I started mapping overtaking=* tags back 
in 2009, I've found that there's a border case that
the current values can't convey thoroughly:

On a multilane (3+) undivided road, overtaking 
in the direction with two or more lanes may be 
- forbidden only if using the opposite direction 
  lanes (appropriate solid line)
- forbidden regardless of the lane used ( =no )
- allowed on all lanes (given no oncoming traffic 
  ( =yes)


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