That's news? I've had 154.905MHz programmed into my 2 meter ham radio for a long time. That's the frequency used by the California Highway Patrol (CHP) to relay their dispatch channel to the officer's handheld radio. A relay radio in the patrol car receives the dispatch channel from the main tower, and retransmits it on 154.905 to the handheld units. Similarly, the handheld units transmit to the patrol car, and it uses its more powerful transmitter to relay the transmission back to the dispatcher.
In some areas, the CHP is switching over to digital systems for performing this function. But it still works where I am, in plain old unencrypted unencoded FM. I can often hear dispatch traffic, and when I do, the signal strength gives me a good idea of how close the patrol car is. There has been more than one time when it has alerted me to a potentially dangerous situation in front of me, or a crazy speeding driver behind me headed my way.
In the US, in many states, it's legal for anyone to monitor police communications, even while driving. But not in all states. However, even in those states which generally outlaw mobile scanner use, they've got an exception for licensed ham radio operators using the receivers built into their ham radio units.
But the frequencies to use vary widely from place to place over here.