Hi, thanks for being open to discussion, and sorry for the delay in replying. I suppose my question would be, who is taking this road in order for it to be considered a trunk route, that is, one of the main routes in the state's road network? What destinations does it serve that merit this importance? If it connects some of the suburbs to central area, I think that's sufficient, but it looks like it just heads into farmland, near towns like Sanger, and eventually the mountains, which seems more like a highway=primary to me. But I assume you're local (given your username ;)), so you might have some insight into local use patterns that I do not. What the guidelines mostly try to steer away from is just tagging a road as highway=trunk because it has a high speed limit or "expressway" features, instead focusing more on its importance to the network.

Also, one of the principles of the classification scheme is to emphasize connectivity and minimize "spurs" where roads of a certain class don't connect at each end with a road of equal or higher class. This isn't always right, since sometimes roads do decrease in importance gradually as you leave an urban area, and I could see CA 180 being one of those exceptions to some extent. It just seems more likely to me (again, from afar) that this cutoff is somewhat west of Reed Ave., since it looks like it is surrounded by farmland, not residents, from the point the freeway ends. Maybe Academy is more reasonable, though I'm still a bit skeptical it has to be trunk at all.

Let me know what you think!

Best,
Will