I saw a good article on c/upliftingnews about AI improving traffic signal controllers. It's good and all, I just can't help but think of the "look at what they need to have a fraction of our power" meme while reading it
Yeah I think scribbling out the 30% with a 100% and saying "roundabouts" would make for a pretty good punchline. I figured I'd get complaints about AI being quick and low cost compared to road construction, which is why I ended up going with the "bikes" punchline instead.
Roundabouts are great but it's expensive to convert a crossing to a roundabout, not to mention difficult since the traffic needs to be rerouted during construction. In the most congested areas it's almost impossible, which is ironically where it is needed the most
Additionally (I still love roundabouts) there can be a max-wait-time problem when there is heavy traffic in one direction.
If a basketball game ends there can be 20,000 cars bumper-to-bumper trying to leave. Let's say (looking at a map) they're going left-to-right through an intersection.
If there's 1 car trying to go top-to-bottom...
If the intersection is a stoplight it doesn't matter. Even if there were 20 million left-to-right cars; it's still a 5 or 10min wait for the top-to-bottom car.
If the intersection was a stop sign it also doesn't matter; it'll be the left-to-right cars turn then the top-to-bottom cars turn
At a roundabout though (at least in the US), vehicles entering on the left always take priority over vehicles entering from the bottom. So the top-to-bottom guy could be there all night
Game days on my campus can cause a 2 hour wait on a 1 mile road. My campus is unusual, but just FYI absolutely insane wait times do happen regularly in some cities.
I think this is a US problem. In europe roundabouts seem much more popular - drivers are aware of the rules and bikes seem to go along fine.
However, roundabouts are only efficient if all connected roads are about equally frequently taken. If one main road and three small connectors are on the same roundabout, the small ones may end up being softlocked.