[Tagging] improve tagging of traffic_calming

[John Willis]

> On Nov 22, 2015, at 12:16 AM, Gerd Petermann <gpetermann_muenchen at hotmail.com> wrote:
> 
> highway=traffic_calming for the small way segments when we tell them
> to use it for nodes. My understanding is that this is not wanted.

I have a question about this. 

If I am mapping from the newest  ~5cm imagery in Tokyo, I can draw the exact boundaries of roadway, islands, fences, and hedges. I can mark crosswalks exactly where they start and end, where every limit line for a signal is, and the exact position of bollards, light poles and individual rocks In a pond. 

If a traffic calming device, like a table or chicane is is meters wide, and affects an easily mappable section of a road - why is adding it to a way segment bad? I would assume (without understanding the downside) that I would be doing a better job of mapping it than with just a node - especially if the road has two way traffic on a single way. 

I am a total noob on why a way would be bad - can someone explain it or point me to the proper wiki page for it?

Javbw