The City of Austin is looking at a unorthodox mass transit plan to install gondolas throughout the city. Apparently, it can move just as many people as light rail can at 1/10th the cost, while taking up a lot less valuable ground real estate. Since the trams move in the open air, they do not compete in terms of road space against cars and buses. Traffic on the ground can maintain its normal pace.
These gondolas are computer programmed to run at a certain speed and certain consistency. More trams can easily be added and taken away on the system depending on the needs of traffic. The trams do not need drivers to operate, which means they cost less to operate. As they never come to a complete stop but merely slow down for passengers to hop on, they are not going to get backed up behind each too much - which is a frequent problem with streetcars.
Overall, I find it to be a fascinating idea. But I have a hard time imagining these things being able to replace streetcars, buses, or ground transit. Ground transit is easier for people to hop on and switch between modes of transit (bike to bus for instance). I also can not see these things reaching the high speeds necessary to move long distances. People will also complain about the way these things look up in the air. They can be a bit of eyesore. The opposition will sit up fear by talking about them falling out of the sky.
The practical place I see a use for these things are in highly urban areas, where they can be built into skyscrapers. No one on the ground floor will every see them, yet they could serve the populace once individuals take high-speed elevators to access them. Coming out of a central terminal (like Union Station), traffic is so high that local buses and trains for the immediate area are inconvenient. Gondolas can serve these routes, therefore frees up other forms of transit for longer distances.
You can find more information about it here: