What we can quantify is the economic impact the San Antonio River Walk has or the impact the Atlanta Beltline has which is billions of dollars in added economic activity. Based on those examples, likely it will increase the NYC GDP by millions if not hundreds of millions. We can prove with dollar amounts getting rid of cars in these cases increase the GDP by billions but in NYC they are only decreasing them so probably won't have the positive impact completely getting rid of cars does.
In terms of real economic output I'd guess it helped a bit as it made things quicker for workmen who needed to get around while reducing the more leisure driving. But we've had lots of much larger changes like covid and brexit that would probably drown things out in the numbers.
A sudden decrease in car crash would probably decrease the GDP the year it happen, then the fact that less people are dying or disabled would probably increase it in the long run. It will probably have the same effect here.