No Drivers
 

The main disadvantage of public transport is that it requires drivers, and the driver is not only the most expensive but also the most dangerous part of the equation.

http://www.nrc.nl/international/Feat..._have_a_driver


http://www.time-compression.com/x/gu....html?id=10785

I believe that the Tyne and Wear Metro (and the Docklands Light Railway) are capable of operating without drivers. The cabs are obscured so that the passengers are unable to see whether they are occupied or not.