Main difference between the Monterey and Santa Cruz branch lines is that Santa Cruz acquired a still partially functional railroad line connected to the national system; Monterey didn't. IIRC from my last visit to the area (many years ago) there's a trail along parts of it, especially but not exclusively the section beyond Sand City where the rails are gone. But I just don't see new rail service on that line within most of our lifetimes, if ever. Under those circumstances, turning part of it into a bus lane makes all sorts of sense. The Highway 1 freeway is a driving disaster on weekends and other times when it's full of tourists (including many that would meet the criteria for the new term "touron" ... look it up). Personal experience of that, having lived and visited with family in the Monterey Bay area. Having a bypass for that to use with regional-access buses would greatly improve schedule reliability. Most likely, it would be in the more central areas, since the rail line doesn't actually go to Salinas (would need to use normal roads for that, probably through Marina like the current through routes run). Of course, something that reaches Castroville, which the rail ROW does, would also help tie the area to Santa Cruz.