That will create backups onto US 1 in Trenton, as the ramp to access the free bridge is quite short.
Few enough people use it as it is that I disagree.
I pass by that ramp to Warren St. every night on my way home. Even in this reduced traffic environment, significant traffic exits there to avoid the toll. (Before then, it was not unusual to see backups onto the highway because of the short decel lane length and nearby Center St. overpass.) I don't think the exiting volume will go that much higher, though.
There was a toll hike that resulted in a massive exodus off of US 1 at Market Street; so much so that I think they even rolled back the toll hike a bit. Originally I thought this was in 2011, but the hike was only 75 cents to $1.00, so now I'm thinking this may have actually happened in 2003 when the toll was hiked from 50 cents to 75 cents. I think the toll hike may have even originally been 50 cents to $1.00, then rolled back to 75 cents. My memory is a bit hazy from 18 years ago, and the internet is very hazy from that time period, but I do remember quite an issue resulting from the toll hike and heavy delays due to a heavy dose of shunpiking with the easily accessible free bridge nearby.
Looking at their 2019 Financials (
http://www.drjtbc.org/wp-content/uploads/2019-DRJTBC-AUDIT.pdf , Pages 71 & 73)(2020 isn't published yet), only about 69% of their car transactions at the US 1 toll plaza were EZ Pass. Frankly, that seems a bit low for the general area. There was 2,706,454 $1 car transactions, or about 7,660 vehicles per day, that paid with cash. If just a small fraction of that amount decides to escape US 1 via Market Street in Trenton, that can cause quite a delay at that interchange.
Obviously, the DRJTBC is hoping people are just going to get EZ Pass and stay on their tolled bridges, rather than sit in congestion finding another way to avoid the $3 cash toll. Hopefully they have a good idea how many they project are willing to finally make that switch.