This is vitally important information. They have gone from boarding buses at the terminals, to forcing them to stop so they can board them.
they also have gone from searching cars only at checkpoints to stopping cars on the road.

Everybody needs to know that ICE has been caught using illegal warrants for stopping cars, for invading homes, so I would expect the same for the stopping of buses.

ICE can legally use an administrative warrant, signed by an ICE agent, stating that a specific person is being designated for possible arrest and possible deportation proceedings. But to do that, they have to know the person's name to put on the warrant. It is NOT a warrant that can be used to stop cars and buses on the highway, and cannot be used to make people show ID.

If a warrant is signed by a judge, it is legal. But again, a judge would only sign if they had details that indicated suspected illegal activity, and lists who/where to search, specifically.

This is a handy site that can be shared, about civil rights.
https://www.aclu.org/know-your-rights/immigrants-rights/