There were two light rail lines built in the middle of freeways in the 1970s in California - VTA and the Green Line in LA. In both cases, they were "mitigation" measures for building a freeway - new freeways not approvable things at the time by themselves, especially expensive ones in a developed urban area. Similar characteristics affected both: rapid transit-like operation in the freeway, but limitations elsewhere; and difficulties with station access (in the middle of the freeway).

VTA, of course, had all that money spent by Caltrans to build the freeway portion, but not enough to build a useful (i.e. subway or elevated) section through downtown - so a pretty face was put on it with the light rail trains sharing space with a trolley car (now gone) that would shuttle between City Hall and downtown. And there never was enough money again to do anything about that downtown crawl. (IMO if they're going to spend the better part of a $billion on light rail in San Jose, I'd say something that fixes downtown would be more operationally effective, if not cost-effective, than an extension to Eastridge; but what do I, a common troll, know?).

Anyway, there seem to be some parallels with the LA Green Line. Built as mitigation as part of an Evil Freeway (i.e. no actual transit planning as we now understand it); ends that kind of petered out instead of going where they were needed (i.e. LAX and Norwalk Metrolink); very low ridership (though that has perhaps improved in LA, since there are simply more people there and it does provide access to jobs and connects with the heavily used Blue Line); unlike San Jose, it has little or no surface running especially at 5 mph on the sidewalk); and short trains (does the Green Line have a 2-car limit like VTA?).

Essentially, both systems were built because the freeway people had to do something that looked like mitigation for the car traffic they were adding, and a nice light rail line looks nice doesn't it? We built it, now it's up to you (transit agency) to do something with it. LA seems to have found the resources to do something with it even if the situation is not ideal. VTA is still fumbling, and has nowhere near enough money to fix it right though they do seem to be able to find money for questionable extensions.