ATCBob

It was a few years back anyway. I was in a group that studied the area's implementation of ADS-B and I remember a number of those routes are beyond radar for various short distances. They'd use time and altitude separation at fixes like BITOD though you'd still stay on VHF as usual, and when you got into range the next facility would re-identify you. A lot of gaps are small enough you don't need to give time estimates, but technically they're using procedural/non-radar control there.