Google maps traffic data is live
Are you sure? Compare before/after for the main affected regions (Holland Tunnel, Queensboro) versus the unaffected regions. We definitely need more data, but I think there's an immediate reduction in the obvious places.
According to this data, traffic is reduced on the bridges and tunnels but not within Manhattan itself, e.g., going from Hell's Kitchen to Midtown East or Greenwich Village to Alphabet City.
I will say, being in Manhattan, their seems to be less traffic on the road. I wonder if Google Maps traffic data is using a rolling average of ~7 days or something