I just noticed this for the first time today. You'll now find a Traffic button on the upper righthand corner of a Google Map page. It can be combined with any of the other options, for example, try this link:
http://maps.google.com/maps?f=q&hl=...,-74.963837&spn=0.339759,0.625534&t=h&layer=t
http://maps.google.com/maps?f=q&hl=...,-74.963837&spn=0.339759,0.625534&t=h&layer=t