The bigger issue for pedestrian injuries on Manhattan's streets is box-blocking and hazardous turns, not really speed. Congestion pricing will probably cause a slight increase in average speeds, but we're talking about going from 5 MPH to maybe 10[1]. It's not ever going to be fast for cars, just faster.

[1]: https://www.latimes.com/nation/la-na-new-york-traffic-manhat...