I swear if the US could build regular roundabouts, converting an intersection would make the accident rate go down, instead of up.
The problem is that at intersections the normative behavior of American drivers is to queue and wait for your turn. Roundabouts assume a different behavior based on jumping the line.
Thus there is a lot of unpredictability regarding other drivers due to generations of driving patterns developed in diverse regional driving cultures...many of which are distinctly not-urban.
In addition, this roundabout is part of an Interstate Highway interchange. The US Interstate system is at a scale that doesn't occur elsewhere. It is transcontinental.
It has a lot of intersections.
Reconfiguring intersections is expensive and disruptive. Stop signs and traffic lights take less space and are often the simplest thing that might work.
I don't think it's that different from turning right on red, or left without an arrow, or even merging on to the highway from an onramp (maybe that's the most similar, traffic in the others aren't flowing the same direction as you).
American drivers don’t know that a yield doesn’t require a stop and can’t think more than one or two seconds ahead of any possible conflict in traffic.
Onramps with traffic lights are a thing in the US. They operate during rush hour.
That said I have yet to drive through a roundabout that I think improved an intersection in any meaningful way. Half of them work as intended but I find them less pleasant to drive through, the other half are just horribly designed and often have semitrucks go through them when they aren't really large enough for that.
That's the argument I keep hearing, but I'm not sure I buy it. Fewer people might be injured physically but even low speed accidents can cost thousands in repairs if not total your car, so going from a few people being hurt a year to multiple people losing their cars or being forced to pay out thousands every few weeks doesn't seem like a win to me.
"Studies of intersections in the United States converted from traffic signals or stop signs to roundabouts have found reductions in injury crashes of 72%-80% and reductions in all crashes of 35%-47%"
https://www.iihs.org/research-areas/roundabouts#safety-benef...