Money.


Or to put it another way:


Money money money.


Technically it's not an issue, we've had ATO (Automatic Train Operation) for a long time now. Julie's point is interesting: It's important to realise that a train driver can VERY rarely avoid hitting an obstruction by applying the brakes, but they are there to deal with the aftermath. It's like aircraft, simplistically modern airliners are almost completely flown under autopilot, the pilot's there to cope when things go wrong.


We will see higher levels of automation (possibly full automation) as ERTMS level 3 (in-cab) signalling gets rolled out, but it is expensive and it will take time.


It is a very interesting question, from my point of view the other way around. As James says, on the whole autonomous trains are much easier - they have defined routes, the signalling system knows where they all are and where they are going, and the installation and maintenance is very heavily regulated to maintain the safety. (Although there is an issue in the length of time they take to stop - I've just been reading an incident report where a train travelled 3.22 MILES after the brakes were applied at 64 mph. Which is why it is a really bad idea to cross in front of a train at a level crossing!)


So my question would be: why do we think autonomous road vehicles will be so much easier? I have a feeling that after a few high profile accidents involving autonomous vehicles we might see a slowing down of the programme. Or maybe, as a society, we will just accept a level of risk on the roads (compared to the railways) that is even higher than it is now.


This is because overall there are much bigger reasons to make road vehicles autonomous than rail vehicles. On large high speed trains, as I mentioned above, you will probably still want a person in the cab anyway to deal with the unexpected, so you need a good reason for them NOT to be driving. And when you take the actual number of fatalities due to train driver error in the UK (for example none afaik in 2015-16) compared to road fatalities, together with the cost of installing automated systems, it becomes a difficult argument.


Whereas with cars there is a huge advantage in autonomous vehicles: it means you can tap away on your laptop, have lunch, take a nap. The enormous (and, I believe, hugely underestimated) challenge now is to make such road vehicles no more unsafe than they already are with a human driver! 


P.S. Although I work as a functional safety assessor, the views expressed above are entirely my personal opinions.

Money.


Or to put it another way:


Money money money.


Technically it's not an issue, we've had ATO (Automatic Train Operation) for a long time now. Julie's point is interesting: It's important to realise that a train driver can VERY rarely avoid hitting an obstruction by applying the brakes, but they are there to deal with the aftermath. It's like aircraft, simplistically modern airliners are almost completely flown under autopilot, the pilot's there to cope when things go wrong.


We will see higher levels of automation (possibly full automation) as ERTMS level 3 (in-cab) signalling gets rolled out, but it is expensive and it will take time.


It is a very interesting question, from my point of view the other way around. As James says, on the whole autonomous trains are much easier - they have defined routes, the signalling system knows where they all are and where they are going, and the installation and maintenance is very heavily regulated to maintain the safety. (Although there is an issue in the length of time they take to stop - I've just been reading an incident report where a train travelled 3.22 MILES after the brakes were applied at 64 mph. Which is why it is a really bad idea to cross in front of a train at a level crossing!)


So my question would be: why do we think autonomous road vehicles will be so much easier? I have a feeling that after a few high profile accidents involving autonomous vehicles we might see a slowing down of the programme. Or maybe, as a society, we will just accept a level of risk on the roads (compared to the railways) that is even higher than it is now.


This is because overall there are much bigger reasons to make road vehicles autonomous than rail vehicles. On large high speed trains, as I mentioned above, you will probably still want a person in the cab anyway to deal with the unexpected, so you need a good reason for them NOT to be driving. And when you take the actual number of fatalities due to train driver error in the UK (for example none afaik in 2015-16) compared to road fatalities, together with the cost of installing automated systems, it becomes a difficult argument.


Whereas with cars there is a huge advantage in autonomous vehicles: it means you can tap away on your laptop, have lunch, take a nap. The enormous (and, I believe, hugely underestimated) challenge now is to make such road vehicles no more unsafe than they already are with a human driver! 


P.S. Although I work as a functional safety assessor, the views expressed above are entirely my personal opinions.