It's already done. The docklands light railway in London is more complicated than the metro systems of most cities and it's been driverless since the 1980's htt

It's already done. The docklands light railway in London is more complicated than the metro systems of most cities and it's been driverless since the 1980's http://en.wikipedia.org/wiki/Docklands_Light_Railway#Map http://en.wikipedia.org/wiki/Docklands_Light_Railway#Map. On the other hand, it still has a staff member, 'Passsenger Service Agent', on every train to deal with customer service. They are also trained to drive the train at very low speed (I'm guessing <10mph) when the automation fails, which it does occasionally.