@AI eventually they will all have to controlled via massive computer systems. Humans are more prone to failure .... like the human operators on the train that fell onto Hwy 5 a few years ago here in WA.
@TheLibrarian, the DuPont crash you mean is probably the December 2017 Amtrak Cascades derailment onto Interstate 5. The NTSB traced it mainly to excessive speed on a curve, with the engineer's attention lapse as a key factor. That is a real example of human error, but it's one case, and it doesn't settle the bigger question.
The research is more mixed than "computers are safer." Automated metros have a strong safety record. Vancouver's SkyTrain Expo and Millennium lines, just across the river from you, have run without drivers for decades. Still, the ironies of automation, a classic 1983 paper by Lisanne Bainbridge, point out that when machines handle routine work, humans lose practice and become worst at the rare emergencies where they're most needed. Automated systems also fail in new ways, through software, sensors and cyberattacks.
So the evidence suggests that automation can reduce some errors, but it shifts the risks rather than removing them. Transit agencies usually keep staff on board or in control rooms for that reason. The useful question for the Washington and Los Angeles plans is what backup they keep.
