Reactive measures usually include some combination of grounding or pulling the mode of transportation out of service, plus a full-fledged investigation into how the system failed to avoid a casualty or near-casualty event, such as the 7000-series derailment in October.
Apply that same logic to incidents caused by personal vehicles, and you quickly spot the difference. Traffic violence is one of the highest non-disease causes of death in the US; as noted above, the odds of dying in a car crash throughout your lifetime is around one in a hundred. The same analysis from the National Safety Council puts your chances of dying in a plane crash or transit in the same risk zone as being killed by lightning: literally too small to calculate.
But our legal system and the media both apply a much lower standard of safety when it comes to vehicular violence. (Our legal system goes even further, to grossly subsidize driving.) Transportation departments don’t routinely shut down the site of a car crash until we fix a design issue that led to it, even when it happens more than once. Delayed road safety projects produce deadly and tragic results. Authorities don’t often recall all the cars fitting a make or model when it’s involved in repeated crashes (it does happen sometimes if there’s a demonstrable flaw–but what if the issue is not a bug but a feature?). Our own US Department of Transportation promotes the vehicles most likely to kill people if they do crash!
For cars, to the limited extent that traffic authorities do perceive responsibility, it mainly seems to apply to the individual operator. And that leaves out a huge part of the picture–the systems that will keep reproducing the risk, which becomes integral when regulators take action on transit and planes.
My old stomping grounds of Boston also seem to have caught WMATA disease, so this isn’t limited to D.C.
Snark aside, I use mass transit and I obviously don’t want to do on it, but it is far safer than driving. The emphasis on total safety, however, forces people into unsafe transit modes (driving) or means they simply lack alternatives. I won’t pretend that WMATA is a paragon of efficiency and is only hamstrung by excessive safety concerns, but we need trains to run more often, especially during a pandemic* (that limits crowding).
If the politicians who oversaw mass transit actually had to use it, I’m guessing there would be more emphasis on its function, and not the extreme hypervigillance about safety.