[Tagging] Tagging for streets with sharrows?

[Mike N.]

There are a number of local streets being converted from 4-lane to 2 lanes + 
center turn + sharrows.

http://bikehugger.com/2006/12/whats-a-sharrow.html

  What is the best way to tag these - they were  discussed briefly in the 
recent "shoulder, etc" thread, but I can't find any consensus.   I found the 
proposed cycleway=shared_lane , which seems to be as good a solution as any. 
Comments?