[Tagging] Carriageway divider

[Elena ``of Valhalla'']

On 2012-08-19 at 14:09:18 +0200, Markus Lindholm wrote:
> In my opinion it's best to treat legal separation (i.e. solid_line)
> the same way as physical separation, i.e. create two separate
> highways, one in each direction.

This doesn't correspond to reality: I believe that an emergency 
vehicle can cross a solid line, while of course they would 
have problems with a physically separated road.

Also, the presence and style of line in the middle of the road gives 
additional informations that could be useful for the users.

* Dashed line: you can overtake wide veicles; probably related 
  to the available speed and chances to be blocked by something slow.
* No line: this road is not wide enough to have two proper lanes: 
  if you meet another car have to slow down, or possibly even 
  stop; a router can use this information to choose another 
  slighty longer, but wider road, even in the absence of a precise 
  width tag.

-- 
Elena ``of Valhalla''