[Tagging] improve tagging of traffic_calming

[Philip Barnes]

On Fri, 2015-11-20 at 11:22 -0700, Tod Fitch wrote:
> A raised area several feet across with a marked crosswalk on top is
> not uncommon in Silicon Valley and more of them seem to appearing in
> residential areas. I suspect that it is one of the newer ways to
> address the combined issue of traffic calming and pedestrian
> crossing.
> 
> 
Most traffic calming features are not pedestrian crossings.

Where traffic_calming is not a pedestrian crossing then
highway=traffic_calming is the prefered way of tagging.

Phil (trigpoint)