What is stopping line following robots from being used for public transportation

Question

Many cities are investigating the use of AI driven buses for their public transportation systems. These are almost always pre-defined and very static routes.

This seems like a great use case for line following robots. It's already a well established technology and it seemingly has fewer point of potential route failure than an AI - so long as the line is visible, the code just needs to keep the vehicle on that line. Just paint a line on the road and save yourself the difficulty of training an AI to perform complex driving tasks.

I must be missing something. Why are AI driven busses preferred over line following robots?

Answer 1

There are several problem I could see on implementation of line following robot.

1. Line detection problem

Simple visual detection only work in a controlled enviroment. If there is really bad weather or anything that block the line, the robot would simply lost its navigation ability because the line is not visible to the robot.

2. Line maintenance

The line would be degraded over time by natural causes, the robot's wheel or any external cause. The wider the area, the higher the maintenance cost.

3. Position identification problem

Industrial line following robot usually use magnetic tape on line intersection and several other spot to identify its position. The magnetic tape can be lost /tampered/altered making the robot could not identify/misidentify its position.

Answer 2

The scenario you describe assumes that the buses have the dedicated lane with no humans and no other vehicles present. But even in this case, there may be another bus present at front in any place (say the engine failed) and also some (rather stupid) humans as well even regardless of the fence. Hence it really cannot be done without some safety system. It is this safety system that is difficult to design. Not only must it detect where it must stop the bus, it must also be able to ignore that looks like a threat but is not. A shade on the road should be ignored, the open manhole probably not. Child on the road deserves emergency braking (that may endanger other humans inside) but a crow on a road probably less so.

To navigate a normal street, the system must also flawlessly identify all participants of the road traffic and use the road traffic code for navigation (so need to see road signs, traffic lights and road markings).

All this is not easy to do. The system needs to achieve the trustworthiness of at least a certified bus driver. You cannot drive a passenger bus with the ordinary driving license good enough for the light car.