The MTA is trying something new to deter fare evaders just weeks after installing spikes on some subway turnstiles.

I do understand why they did it that way because it’s probably inexpensive for them,” a rider said. “It’s just adding a small piece instead of changing the entire design.”

The MTA is trying to get a leg up on turnstile jumpers at the Brooklyn Bridge-City Hall/Chambers Street subway station. Crescent-shaped metal shields attached Tuesday to a bank of turnstiles at the Lower Manhattan complex are the MTA’s latest attempt to curb a fare-evasion crisis that last year cost the transit agency an estimated $360