Yonge Street through Richmond Hill's downtown (between Major Mac and just south of Elgin Mills) is probably the worst stretch that I've seen, since the narrow ROW and mid-day on-street parking essentially allows just one travel lane in each direction. VIVA is supposed to operate in mixed traffic through there as well, though I've heard that York Region may be asking Richmond Hill if they are willing to convert the mid-day on-street parking lane into a bus-only or HOV lane through that stretch.