so they do whatever speed they want, slam on their brakes right before the cameras, crawl past them at ridiculously low speeds, get out of range, and then just go right back to doing whatever speed they want.

if it was ever actually about safety, we would be using physics to slow cars down rather than cameras

That’s why average speed cameras are now the preferred traffic calming measures on long roads. You can’t avoid ¯v = ∆s / ∆t, you have to stay under a certain speed while you’re between cameras.