You ever see a dog that’s got its leash tangled the long way round a table leg, and it just cannot grasp what the problem is or how to fix it? It can see all the components laid out in front of it, but it’s never going to make the connection.
Obviously some dog breeds are smarter than others, ditto individual dogs - but you get the concept.
Is there an equivalent for humans? What ridiculously simple concept would have aliens facetentacling as they see us stumble around and utterly fail to reason about it?
You forgot one solution.
Teaching people how to drive safe and smart. Way too many people focus on the car in front of them instead of the traffic ahead. If you watch for brake lights as far up as you can see and let off the gas when appropriate, not only will you be less likely to be in or cause a wreck, you will also save wear and tear on your brakes and use less gas (even more pronounced with regenerative braking).
In addition to the above. When you are driving a route you know well, get the fuck over from which ever side is more likely to be used to turn off. For most highways this means moving left before you near an onramp. Plan ahead and get over before you need to do so you don’t have to speed up or slow down to let people in.
That won’t help much. By the time anyone notices the roads are slowing down there are six times as many cars on it as it can safely handle. Driving skills will help on backroads, but that isn’t where most people are driving. No amount of training can make heavy traffic safe.
Driving safely and smart is essential for other reasons, it does prevent additional bottlenecks (you mentioned one, wreckages), and it reduces the impact of the unavoidable bottlenecks (because the cars won’t waste so much time re-accelerating after them). But if my reasoning is correct, most of the time there isn’t much that drivers can do against traffic besides “don’t use the car”.