The MTA is expanding its effort to curb fare evasion by adding a built-in delay to emergency exit doors at more than 100 subway stations.

The agency says the 15-second delay is meant to slow what it calls a “superhighway” of fare evasion — the kind that happens when riders open the emergency gate after paying and others slip in behind them without tapping.

Under the new system, pushing the handle from inside triggers an alarm that sounds for 15 seconds before the door unlocks. The MTA says the technology is designed to stop people from entering without paying, not to trap riders trying to exit.

Some riders, however, say the delay could pose a safety risk during an actual emergency, when they may need to get out immediately.

Fare evasion is down since the system was introduced, according to the MTA, which said in a statement: “NYC Transit employees can release gates immediately if necessary. The program was evaluated as safe under New York State Building and Fire Codes.”