BART is stepping up its crackdown on fare evasion , rolling out faster-closing gates aimed at riders who continue to cheat the system. Transit officials are now testing upgraded barriers at Antioch and Concord stations that shut in 500 milliseconds, down from the current 800 milliseconds. Officials hope that 0.3 seconds makes the difference. The goal is to stop “piggybacking,” when someone sneaks in right behind a paying rider. The push comes even as BART claims its new gates, first installed in late 2023, are already reducing fare evasion. The goal is to stop “piggybacking,” when someone sneaks in right behind a paying rider. NART via YouTube Before the upgrades, BART was losing about $25 million a year to fare evasion. Getty Images The old 1970s-era turnstiles were easy to jump or squeeze through. BART A rider poll found 17% of respondents said they saw someone skip paying, compared to 25% the year before, SFist reported.…