[mcny]

Someone said a few weeks ago that buses that run very often on the same route is just a very expensive train.

I think for self driving to realy work well, we have to ban humans from driving (and perhaps make it a felony to interfere with a self driving bus the same way we cover assault on a bus driver).

I thought it would be easier to implement self driving trains than to implement self driving cars. Who is working on that?

[adrianN]

Having worked with trains I'd guess that frequently running busses are actually very cheap trains. Rail infrastructure is incredibly expensive.

[mcny]

> Rail infrastructure is incredibly expensive.

I didn't know that but I assumed it would be cheaper than roads? I mean four tracks of trains (two local, two express) compared to four lanes of road?

[Piskvorrr]

Roads are dirt-cheap (pardon the pun) compared to rail: first off, a road requires an order of magnitude lower precision, can scale significantly steeper grades, and allows for curves and stopping distances that on rail would be considered insufficient. Next, operating it is a dark art in itself - scheduling, communication, safety, etc.; a highway through nowhere just needs asphalt and it just lays there, a railway needs active elements. And to top it off, there's maintenance: a 2-inch bump in a road is normal, in a railway it's a major defect. Worse, rerouting around a closed section is not a simple matter of setting up traffic cones.

All of that is expensive - like the difference between 80% and 99.9% reliability.

[beojan]

> I thought it would be easier to implement self driving trains than to implement self driving cars. Who is working on that?

We already have self-driving light rail systems (London's DLR for instance).

[Piskvorrr]

...and much of the normal rail is running at Level 3-Level 4 equivalent.