Scan they do it?

After some earlier pilots, so-called gun scanners are making their debut on the subway, with Mayor Adams and MTA officials announcing yesterday that the imposing machines would be coming to select stations within a few months. The city has previously deployed scanners manufactured by the company Evolv at sites including Citi Field and Jacobi Medical Center.

There is legitimate cause for concern given the spate of notorious stabbings and shootings that have plagued the transit system and added to a sense of fear and foreboding.

But while scanners may offer the appearance of safety, it’s not clear that this technology is ready to be rolled out in a system the massive size of New York’s. The trains carry millions of passengers per day, and the potential externalities of a pervasive surveillance and inspection system must be judged against the crimes that they might have a chance to prevent. The most effective scanning system — the TSA’s familiar airport checkpoints — would slow movement in and out of the subways to a crawl.

Moreover, unless the systems are rolled out at all 472 stations — which would require massive manpower, cost and friction — anyone with a gun or a knife could just walk to the next station to enter the system. Actually, they may not even have to, given NYPD Deputy Commissioner of Legal Matters Michael Gerber’s assertion that riders would not be required to pass through the scanners at all. Opt-in security systems, even if they work, seem a bit self-defeating.

We wouldn’t want the scanners to come off as a total bust like the completely useless NYPD subway patrol robot that was retired last month after spending most of its time in the Times Square station just charging.

Meanwhile, the scanners’ known track record of persistent false positives creates the potential for escalation where one doesn’t have to exist, similar in some ways to the issues with false ShotSpotter alerts. If someone is carrying an umbrella in a bag, and officers present believe they have a gun, there are multiple opportunities for that situation to spiral out of control in ways that can be dangerous to both straphangers and cops.

We understand the impulse; people are worried about the terrible incidents they’ve heard about and clearly not reassured by the broader statistics showing that riding the subway is incredibly safe (far safer than commuting by car). It’s the mayor’s and governor’s responsibility to reassure New Yorkers, but that should mean taking the most efficient steps towards ensuring safety, which is the high expense of more transit cops and helping people access services that will keep them from causing trouble on the trains.

For example, funding and expanding overdose prevention centers — which the governor has thus far pointedly refused to consider — would give some substance abusers space to safely consume drugs and, ideally, embark on the path to kicking the dependency.

The city and the state have separate mental health outreach efforts and are now expanding their joint program. Excellent, as the subway is no place for someone who is not well.

Rather than spend more money on these scanners, we should double down on proven and less intrusive strategies. Gumming up subway entrances isn’t the answer.