Caltrans explores 140mph 'bullet buses' between L.A. and San Francisco

I don't think that people expect them to complete it.

The article describes an exploratory program -- and one which I don't think can be done -- in the same spirit as that DARPA program where they hoped to make a pill that would enable people to digest grass and leaves.

After all, people know how to build bullet trains and make them safe and fast. Nobody has ever built a 140 MPH wheeled transport network; a variety of speculative technologies would need to be developed, and it's not clear that it can be done in a way that's safe or energy-efficient.

It's not something you need to complete. A bullet train is worthless if you don't make an entire line. A bullet bus is just an upgrade to an existing bus route. Suppose you create a busway, but never manage to get the buses on it to go above 85mph. That's still a win. Suppose you do let them go at 140mph, but only on some sections. That's still a win. You can do it incrementally and stop at any point, and still reap the benefits.

It's also something that deliberately takes advantage of existing rights of way rather than trying to forge new ones. Hence it would have a vastly lower propensity to get mired in litigation from every hamlet along the way.