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In many places, road engineers deliberately obscure visibility of the roundabout from the approaches. So even if it is legally a 'yield', in practice, stopping

In many places, road engineers deliberately obscure visibility of the roundabout from the approaches. So even if it is legally a 'yield', in practice, stopping is enforced by unaccountable manipulation. Yet another example of LCD governance imposed by the crazy minority - in this case, those who would not yield correctly (see Skin In The Game, NNTaleb). Always remember that 50% of drivers are below average intelligence.

blattimwind 8y ago
> In many places, road engineers deliberately obscure visibility of the roundabout from the approaches. So even if it is legally a 'yield', in practice, stopping is enforced by unaccountable manipulation. Besides that, many after-the-fact roundabouts are so small in diameter that the indicators on almost every car model are invisible, so there is essentially no way to actually tell if someone is taking an exit until they do it. Lots of unnecessary stopping and waiting due to that. Another great thing is having a zebra crossing (preferably combined with a cyclist crossing) on each approach/exit, but planting a bunch of bushes such that it is practically impossible to see people there when approaching the exit, forcing people to crawl speed before exiting, and conversely forcing everyone behind them in the roundabout to brake as well. I'm not sure if stuff like that is intentional or just accidentally stupid.
throwawaymath 8y ago
> Always remember that 50% of drivers are below average intelligence. Well...technically not in this case, no. It's usually misleading to use the median instead of arithmetic mean for measuring averages in population, because you can wind up with situations where, say, 90% of people are "above average." That being said, IQ is specifically calibrated to follow a normal distribution. Ordinarily that would mean you're correct, and we can just call the arithmetic mean and median the same thing. However! The normal distribution of IQ - average 100, standard deviation 15 - includes the bottom percentiles of the population who are severely mentally impaired. These people aren't usually drivers. It follows that when you're driving, the population of drivers around you will actually skew higher in percentile. In fact, it's probably more likely that the modal driver has intelligence equal to or greater than average. Personally, I think safe driving, polite driving and technically skilled driving are all orthogonal with respect to each other and to overall intelligence. After a very serious accident years ago, I became the kind of person who will only drive at or below the speed limit. But I know several people at least as - and probably much more - intelligent than me who drive "erratically", to put it nicely. I don't think raw intelligence captures enough information to really dictate behavior here.
takk309 8y ago
Traffic engineer here. The purpose of the landscaping in the center island of a roundabout is to block the view across the roundabout and to stop people from driving directly over the central island. The purpose to blocking the view is to make traffic flow better. There are many people that will wait for any vehicle in the circulating lane regardless of that vehicle blocking their path. By blocking the view across the central island, those entering the roundabout can only see so far upstream as matters to their flow. Stopping people from traversing the central island may not be a large issue in an urban environment but in rural settings that is different. The state I live in is very rural and we have some roundabouts that are not near a water supply for irrigation. As such the state DOT tends to use just a mound of gravel (roughly 3/4 to 1 inch aggregate.) It is very common to see tracks going right through the central island, likely lifted trucks thinking it is awesome. Having landscaping in the central island ads something to hit.

blattimwind 8y ago

> In many places, road engineers deliberately obscure visibility of the roundabout from the approaches. So even if it is legally a 'yield', in practice, stopping is enforced by unaccountable manipulation. Besides that, many after-the-fact roundabouts are so small in diameter that the indicators on almost every car model are invisible, so there is essentially no way to actually tell if someone is taking an exit until they do it. Lots of unnecessary stopping and waiting due to that. Another great thing is having a zebra crossing (preferably combined with a cyclist crossing) on each approach/exit, but planting a bunch of bushes such that it is practically impossible to see people there when approaching the exit, forcing people to crawl speed before exiting, and conversely forcing everyone behind them in the roundabout to brake as well. I'm not sure if stuff like that is intentional or just accidentally stupid.

throwawaymath 8y ago

> Always remember that 50% of drivers are below average intelligence. Well...technically not in this case, no. It's usually misleading to use the median instead of arithmetic mean for measuring averages in population, because you can wind up with situations where, say, 90% of people are "above average." That being said, IQ is specifically calibrated to follow a normal distribution. Ordinarily that would mean you're correct, and we can just call the arithmetic mean and median the same thing. However! The normal distribution of IQ - average 100, standard deviation 15 - includes the bottom percentiles of the population who are severely mentally impaired. These people aren't usually drivers. It follows that when you're driving, the population of drivers around you will actually skew higher in percentile. In fact, it's probably more likely that the modal driver has intelligence equal to or greater than average. Personally, I think safe driving, polite driving and technically skilled driving are all orthogonal with respect to each other and to overall intelligence. After a very serious accident years ago, I became the kind of person who will only drive at or below the speed limit. But I know several people at least as - and probably much more - intelligent than me who drive "erratically", to put it nicely. I don't think raw intelligence captures enough information to really dictate behavior here.

takk309 8y ago

Traffic engineer here. The purpose of the landscaping in the center island of a roundabout is to block the view across the roundabout and to stop people from driving directly over the central island. The purpose to blocking the view is to make traffic flow better. There are many people that will wait for any vehicle in the circulating lane regardless of that vehicle blocking their path. By blocking the view across the central island, those entering the roundabout can only see so far upstream as matters to their flow. Stopping people from traversing the central island may not be a large issue in an urban environment but in rural settings that is different. The state I live in is very rural and we have some roundabouts that are not near a water supply for irrigation. As such the state DOT tends to use just a mound of gravel (roughly 3/4 to 1 inch aggregate.) It is very common to see tracks going right through the central island, likely lifted trucks thinking it is awesome. Having landscaping in the central island ads something to hit.