Most of the bridges and tunnels have their own tolls, with a few exceptions like the Brooklyn and Manhattan bridges. One possible explanation is that the advocates were right and the combined bridge/tunnel + congestion toll is enough to dissuade driving into the zone entirely for people arriving via bridge/tunnel, but the lower congestion toll on its own isn't as much of a deterrent if you have access to a free crossing into Manhattan from other boros or were already in Manhattan (outsize of the zone) to begin with.

> I'm not sure how to reconcile the significant drop in the bridge and tunnel commute times with the apparent non-effect on commute times within the congestion relief zone.

Yeah, I'm not sure what to make of that either but it'll be interesting to see when more/better data comes available. Maybe car traffic getting to Manhattan is reduced but those people are using more taxis and Ubers to get around once they're in

It's a bit silly to set a fixed rate.

Here in Singapore, the congestion charging pioneer, we adjust the fee dynamically to keep traffic flowing.