A Pragmatic Approach to Resolving Weapons in Subway Systems and Other Public Venues

By: Peter Evans, Patriot One CEO

I read with interest and sadness as the events unfolded about the tragic subway shooting in New York City earlier this month. The world is becoming a more uncertain place, with a number of contributing factors such as social unrest, poverty, crime, etc. This, combined with easy to access weapons and a crumbling social safety net, are leading to this uptick in violence.

I also read with concern the media stories around the events and proposed weapons detection systems, along with the media call for action to Mayor Eric Adams to implement a “tough on crime” policy. Missing from many of these stories were some of the critical components required for a successful execution of these types of weapons detection technologies. Therefore, people are falling prey to the same marketing exuberance that often accompanies new innovations. This is not reality, at least not yet.

Subways and weapons detectors – an operational nightmare

There are countless opportunities where next-generation weapons detection technology is successfully being deployed today within stadiums, entertainment venues, schools and other facilities. The promise of these systems is that they are weapons-detectors, not metal-detectors, and as a result, can move people in or through a venue up to 10 times faster at significantly lower operational costs. Securely getting thousands of people into a facility quickly, with virtually no lines, is possible right now.

However, following the NYC subway shooting, there were calls for this kind of technology to help prevent attacks like this from happening again. The mayor mentioned the city was already evaluating technology devices to put in place at subway stations to detect weapons before they can cause harm.

While this seems like a great idea on the surface, there are many considerations that are being lost in the over-zealous marketing hype, and grandiose statements such as being “born to solve this problem.” 

The lifecycle of technology

Successful performance of any technology solutions, whether it is your smart phone, your car, a cash register or something as complex as a weapons detection system, is a combination of people, processes and technologies. Technology will always fail, and become an inhibitor, not a benefit, without proper execution of the people and process aspects.  

Further, all technology has a lifecycle, and goes through various maturity stages. In the early stages there are limited successful applications based on the technology maturity. Over time, continuous innovation allows a solution to grow to appropriately address more complex problems. Think about the first smartphones – they did not have a camera, an app store, etc.   They had limited capabilities but fit certain applications well. You would not, or could not, successfully use the first smartphones to buy tickets to sports games, shop online or make a group video call.

Despite all the hype, the reality is that this type of weapons detection technology does have its limitations right now. It is simply a matter of physics and the maturity of technology. Excessive metal objects, excessive clutter, excessive interference from external systems and electromagnetic interference will cause these systems to falsely alert. For example, it’s a known fact that the majority of these systems send out false alerts when a subway train passes nearby. There are hundreds of trains constantly moving in NYC, which is an interesting consideration for this discussion in particular.   

Let’s consider the three minutes prior to the train arriving at the subway stop, when commuter traffic is at its highest. As the train is approaching, the weapons detection system starts lighting up like a Christmas tree with false alerts due to the train, and commuters are incorrectly stopped while, at the same time, they are trying to rush past the system and through the train doors.  An operational nightmare.

Processes, clutter, rush hour and undirected traffic

All security technology, including next-gen weapons detection technology, needs to be staffed by security guards. The systems alert if a patron is carrying a gun, knife or other prohibited item. The alert then needs to be addressed by a human through a well-defined secondary screening process. The guard needs to approach the patron and question them about the weapon in their pocket, and/or conduct a secondary screening which could include bag searches and divesting of personal items. In the context of NYC, this means thousands of security guards would need to be on hand whenever subways are open, for the systems to truly defend from the threat of weapons. In the city, there are over 472 subway stops, with multiple doors, entries and passageways. Right now it is simply not feasible to have fully-trained security guards monitoring every piece of innovative technology at subway stations to properly keep weapons off of the trains and platforms. Amidst the ongoing “Great Resignation,” this would be putting even more pressure on an already strained workforce.

Additionally, the kind of weapons detection technology on the market today cannot detect weapons in a medium-high clutter environment with a high degree of accuracy and the necessary low false positive rate to ensure this is an effective solution. This means backpacks with their typical content, including laptops and chargers, shopping bags, strollers, rolling luggage and all the other paraphernalia that individuals carry on the subway. These common things people are bringing onto subways every day will create false alerts, leading to a significant volume of manual, secondary screenings to ensure weapons are not getting on the trains – which brings us back to staffing.  Even more guards will be required to perform bag searches, separate to staffing the technology.

Lastly, we know the general vibe of rush hour – people sprinting to catch trains and squeezing through the doors as they’re closing, people going into stations already on conference calls or listening to music, or cramming into the small areas where they need to scan their ticket, etc. Now combine the typical subway station flow, with another step of walking through a weapons detector and stopping for frequent secondary screenings. Thus creates a clash of processes. No piece of technology right now can detect weapons 100% of the time, while not alerting to other innocuous items like smart phones or umbrellas. This means, some commuters – in their rush to catch a train – will need to be stopped by guards for a secondary screening, to empty their backpack or to be questioned about what is in their pockets, causing them to miss their train.

Unhappy individuals at high numbers contributes to mobs and added violence as tempers rise.

The key difference here in the consideration of the subway vs. an entertainment venue is it has undirected traffic. Subway riders flow in unpredictable ways, directions and groups. Compare this to where current weapons detection technologies are being deployed. There’s more of a directed and predictable flow; patrons enter sports stadiums generally in single file. Children walk into the front door of the schools generally in an organized manner with very standard and predictable items. The volume of individuals entering the front door of a hospital in a day is significantly lower than the number of people who walk in the front door of a subway station in a minute. These are the situations currently available weapons detection technology are suited for, and those it’s not.

Doing the math

Sometimes a simple equation can help us understand the complex nature of the problem to be solved.

Right now, about three million people pass through the 472 NYC subway stations every day. Before the pandemic peak ridership was six million people. If we ask ourselves the question, “What percentage of riders carry items that are likely to cause next-gen weapon systems to false alert?,” this number would likely be closer to 50%, not the marketing numbers that are being promoted which come from lab environments or very controlled and directed traffic environments.

At its peak this would be three million false alerts, and therefore three million secondary screenings that would need to be conducted every day. That in turn is 6,300 on average for each of the 472 subway stations. Realistically, for a facility like Penn Station, we’ll probably see 10 times that amount or 63,000 secondary screens. 63,000 people who are stopped, asked to step aside, have their bags checked, empty all their pockets, and walk through the system a second time.   

Let’s take this thinking a bit further. One weapons detection solution acknowledges an issue with false alerts for eyeglass cases – 75% of the population needs corrective lenses, and 71% of those are glasses. Therefore 53% of the six million travelers every day will alert for those carrying eyeglass cases.   

For anyone who has travelled through Penn Station at rush hour, this is untenable.

Starting with integrated technology

While a quick fix to securing subways isn’t pragmatic anytime soon, there are discussions that can be had about a more thoughtful approach: an integrated technology system. There are many next-gen solutions out there right now that, if integrated, can make an improvement in the security of undirected environments, such as mass transit systems. One example could be a combined ticket scanner and weapons detector. That way, commuters aren’t needing to pass through two separate systems, and while they are scanning their ticket, a weapons detector could be scanning for weapons.

The need for solution is clear. The concerns of society are not going away. But, we also cannot radically change systems to accommodate the need for a solution. Instead, we need to look at weapons detection solutions in a more practical way, so they fit in and integrate with the existing business and traffic flow, not fight against it. The maturity of technology will occur in time, and there are pragmatic approaches to solve the problem, but right now I caution those to think carefully about the security operations and patron experience, and not be distracted by marketing hype.