I was recently walking my dogs and had a mental image of... you know those yellow, maybe 10 inch diameter steel/concrete cylinders that range from 3' to 5' high that they put up to stop people from driving? Sometimes they're skinnier and can be laid flat for emergency vehicles to pass? In the military, they're (I think) solid steel and (I know) actuated, hidden beneath the pavement until someone fails a checkpoint, then they shoot up (like sometimes through the car) to trap the offender.
I just had this mental image of these things, combined with the "one car on green" CA stoplights at on-ramps, controlling traffic in the tricky places like this. One car on green. No, seriously, ONE car, slowly, on green. Muahahahahahahaha! It'd be bad if a pedestrian stepped outside the crosswalk, though, aside from super expensive.
But why is it that California has a monopoly on the "one car on green" lights at freeway entrances? The third lane could easily be tweaked at SqHl to make the transition much smoother.
I have never understood why we (PA, Allegheny Co, or Pgh) can't implement the ideas that other places have not only thought up, but implemented, for years, successfully. I mean sure we'd rather have the classics to fly-by-night trends, but we've gone beyond retro to borderline prehistoric.