The only true solution would be determining a maximum number of cars we want in manhattan at any point in time and increasing the toll to enter towards infinity as the car count approaches the limit. When people start seeing $50, $100, $500, $1000 whatever tolls they’ll turn around.

It’s a fucking island controlling the number of cars present is very straightforward. Catalina does it to a smaller scale but the idea is the same. All entry points to the island have cameras already so counting the number of cars is easy.