The camera feeds on the subway are going somewhere currently, surely. The processing doesn't need to be done all centrally either, you could have edge compute on the vehicles to analyze the video inputs. False positives are a matter of tuning sensitivity. Briefly mistaking a shiny phone for a knife is not likely to be a problem. I think you would be looking more for patterns of aggressive behaviour or passenger panic as a trigger for security attention.
Currently the cameras are accessible to the drivers cabins at either end of the train, and recordings are collected when needed (
https://www.ttc.ca/en/transparency-and-accountability/policies/video-recording-policy). It does not appear there's any live transmission off the train.
False positives in any kind of AI system are a problem, and tuning can only do so much. It’s the sheer quantity of data, the number of people and their proximity that needs to be analyzed at any given time that is the main problem with putting them on a train. AI is good, but not great at detecting a single human form (see; Tesla/pedestrian collisions for how well current systems actually work -
https://arstechnica.com/cars/2023/0...ing-sees-pedestrian-chooses-not-to-slow-down/). It’s absolutely terrible at knowing what a mass of human beings in close proximity actually is. A packed train full of 1200 people is either going to generate a steady number of anomalous positives or you’re going to have to tune so many out that you’re going to miss real problems. And that’s a much bigger issue.
Even if you could determine intent by physical action via AI (you really can’t right now), there’s the issue of “what is aggressive behaviour”? Rowdy drunkards, sports fans, playing kids would likely trigger systems. Even weapons detection itself (which is most of what AI is capable of at the moment) is gonna go berserk on Toronto Comicon or FanExpo weekends.
And what I haven’t brought up is that current weapons-detection AI isn’t living up to the claims of developers. Most of it isn't 100% camera based, and a lot of it involves passing through body scanners. (
https://theintercept.com/2023/05/07/ai-gun-weapons-detection-schools-evolv/).
Outside of detection, what do you do when something real is happening? The driver can’t leave the cabin. So do you just stop the train at the next station and wait? Do you open the doors allowing a perpetrator to escape (which is generally what happens now), or do you keep them closed and allow more stuff to happen? Detecting violent acts isn't going to stop them from happening. Someone pulling out a knife and stabbing someone will always be faster than AI passed onto a human for verification and the time taken before potential intervention. It will almost always be reactionary and then, what purpose has an AI system served?.
We have passenger alarms that when pressed alert the driver's cabs on which car the alarm was pressed. They were (apparently) pressed during the recent stabbing. This is why having a guardsman on the train is a better overall idea for right now. We shouldn’t have gotten rid of them anyway. Workers and experts said quite loudly that getting rid of them would compromise safety, and look where we are now.
https://www.blogto.com/city/2021/05/ttc-planning-eliminate-subway-guards-and-people-arent-happy/
I think the technology would work well hand-in-hand with additional security/police presence.
I agree the technology would work well, but when it's up to snuff and cost effective. Which is not now.
If the city is going to spend vast gobs of money, it should be addressing the root causes of things like this and not reacting to the symptoms.
I think part of this is not merely dealing with the aftermath of violent events, but to deal with lower level misbehaviour to reduce the feeling of impunity trouble-makers have currently.
A lot of this problem is stemming from just a lack of people within the subway system who were there even 5 years ago. The automation promised with the Toronto Rocket trains and Presto card entry became a way for bean counters to assume that humans were no longer as necessary on the system. The TTC ditched the 2nd person on the train (guardsman), and severely cut back on booth staff.
It used to be common to see staff all over the place in a station, now you're lucky if you see one on your way to the train. As I've mentioned elsewhere, I've been to Bloor-Yonge station (the busiest in the network) and seen the only booth they use now, empty many, many times.
I remember days not so long ago with both booths at that main entrance were always manned. TTC cuts have (like just about every industry) come primarily from labour.
Automation shouldn't be a way to get rid of the humans. By comparison, Tokyo has five lines of fully-automated trains and electronic entry, but even aside from the passenger pushers, there are still gobs of transit workers on platforms, on the train itself and in stations. Most of them are customer service, but a human presence is always felt.