I see the first problem all the time, especially at stoplights. Often when there is a line of cars waiting at a red light, when it turns green someone will remain stopped so that a waiting vehicle on a perpendicular street or nearby business can pull onto the highway in front of them.

They think they're being polite, but they're forcing dozens of cars to wait for an additional cycle of the stoplight, whereas if they had just pulled through the light as normal then the waiting car would get a chance to merge as traffic either cleared or came to a stop again.

"dozens" is quite a bit of hyperbole. I generally only see behavior like this when traffic is dense and the speed of traffic is limited. In those cases, letting someone in doesn't decrease the number of cars that make it through the light. Additionally in those cases, it's quite possible that if nobody lets in the the car trying to merge, they will never be able to merge.

Obviously, optimal behavior is dependent of the traffic conditions.

"Dozens" is not hyperbole at all, my account is an accurate and truthful statement of the traffic conditions in my area and the consequences of those bad actors.

Cars looking to merge should do so as the traffic comes to a stop. A car already on the highway they are looking to merge onto need only stop sooner than they otherwise would, allowing them to pull out into traffic that is already at a standstill.

I'm not sure I understand the traffic conditions you are describing.

Lets take "dozens" to mean "atleast 18" (a dozen and a half). The average car is 15ft so this means to fit the 18 cars bumper to bumper there will need to be at least 270ft between the car you let in and the car in front of it when it passes out of the intersection.

If you leave half a car length between cars and allow the full 2 dozen this number quickly becomes 528ft.

If people are really this slow in pulling out, I feel your pain. However it is these numbers that caused me to judge your anecdote as hyperbole

Additionally, you suggested blanket solution sounds more dangerous as well as completely unworkable in bumper to bumper trafic: "Cars looking to merge should do so as the traffic comes to a stop."

It's far more dangerous to pull out in-front of a moving and already braking car that may or may not see you then to pull out in-front of a stopped car that has indicated that it does.

I see this too, in the bay area. There are so many intersections with green left-turn arrows that drivers forget the rules when they encounter a regular light without a left-turn arrow.

The particular case is that a driver going straight will yield to a driver approaching from the other direction who wants to turn left across them. They should not yield. They have a green light.

Interesting observations. As a counterpoint, there are a couple of roundabouts between here (Phoenix) and Las Vegas, notable both because there's often fairly heavy traffic and that almost everyone on the road is from elsewhere (and therefore unfamiliar). They seem to operate quite smoothly, and are a welcome break from waiting for several cycles of traffic lights.

I'm curious... where have you seen these troubles? Perhaps the small radius is the real issue?

Simple educations campaigns would solve the driver education issue. Get all networks to run ads with celebrities showing how to drive in a roundabout. You could throw in some non-texting message while at it.

The ignorance argument is difficult to agree with because every country has had to introduce them to an uneducated population at some point. You could have used the same argument against traffic lights.

It seems that the slight inefficiencies you cite in the first complaint would eliminate the phenomenon described in the second complaint.

The point of roads is not to transport any particular traveler at the greatest possible speed, but rather to transport all of us in safe and convenient fashion.

The first problem is a problem with US drivers in general. I don't know what we should do about it, except perhaps test people's driving abilities more frequently. I, for one, honk at people who fuck up my roundabout experience.

I think the second problem is an acceptable tradeoff, but ymmv

There are a couple of roundabouts where I live, and I see the second problem all the time. The best (worst?) was someone who came to the entrance, stopped, sat there for about 3 seconds and then went when there was a car coming in the roundabout and nearly caused a collision.