The way the road transport industry approaches safety in general is decades behind the air, maritime and rail industries. Investigations, where carried out at all, are performed by the police with a view to potential prosecution. The findings of those investigations are not made publicly available. And the blame for accidents is almost always laid exclusively on the driver(s) involved.
Compare that to the much more holistic view of accidents taken by the AAIB, MAIB, and RAIB, where everything up to and including the way the infrastructure was designed generations ago may be treated as a contributing factor. Even where the accident is genuinely due to human error, the questions 'why did the human make the error' and 'why did the error have those consequences' get asked. On the roads, they aren't.
The result, of course, is that minimally-trained drivers are allowed free rein over virtually the entire road network in almost all circumstances and with negligible oversight. The effect on safety is obvious!
Of course, the decision to run more trains, less safely, to decrease risk for the transport system as a whole isn't one that rail managers can take. If (when) there is an accident under such a regime, it's very easy to point at the consequences. It's very hard to point at the road accidents that didn't happen.