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Having driven in the UK and coming back to the US I miss all of the roundabouts. Any reason (aside from contractor profits) towns use 4-way traffic light system

• 0x3f 7mo ago
  Having driven in both, Americans don't take naturally to roundabouts and it would be difficult to teach all the existing drivers about them. Same in the UK when they add new rules: most drivers remain completely unaware of them.
  • Detrytus 7mo ago
    There’s nothing complicated about roundabouts: entering it is like joining the traffic from a parking lot/your own driveway, exiting it is like exiting a highway.
    • 0x3f 7mo ago
      It's not exactly the same though You yield to traffic from the left, which mean someone from a leftward entrance has priority, but they can actually be blocked by other traffic. So you have to not only consider yielding to them, but also whether they are yielding to someone else, thus giving you space to go. I see this computation mess people up all the time. Also, judging intentions is much harder. On a multi-lane highway, it's very clear when someone is cutting across lanes to exit. And there's only one place they can be exiting. On a multi-lane roundabout, they might be taking the exit before your entrance, or the one after. Often people won't be signalling, or even giving incorrect signals. When joining as well, if I'm emerging onto a busy road with two lanes in the direction I'm going, I will probably accept joining when the nearest lane is clear, even if the next lane is not, as long as the cars there don't look to be moving into the nearest lane. On a roundabout people can peel off at any time, and you should really wait until there's a gap in all lanes.
  • unselect5917 7mo ago
    The only difference is Americans aren't yet used to them because they're uncommon. You fix that by making them common. It's not like there's a genetic difference in Europe that makes them capable of roundabouts and Americans not.
    • 0x3f 7mo ago
      Roundabouts were introduced in the UK back when car penetration was low and every learner for decades has been indoctrinated into how to use them. It's the education piece that's the problem. People don't intuitively understand roundabouts and you can't magically send that knowledge to millions of existing drivers. In some sense you have to start sometime, but there's going to be pushback from the accidents and injuries that will certainly happen in the interim.
      • db48x 7mo ago
        No, this is just making excuses for not building them. Once you start using them in an area even the drivers that have never used them before will figure out how they work. It’s not rocket science. > there's going to be pushback from the accidents and injuries that will certainly happen in the interim. In areas that have actually built lots of roundabouts the accident and injury rate dropped immediately. There was no interim period with higher accident rates.
• boc 7mo ago
  Traffic lights can be tuned to create "green waves" that allows for efficient flow of traffic along arteries through a city. You can adjust the timing throughout the day to help alleviate congestion. In rural areas, heavy machinery/commercial vehicles may need to make a very wide turn through the intersection. Traffic circles are fine for a lot of applications but they aren't strictly better than lights in all circumstances.
  • 0x3f 7mo ago
    I don't see how that could possibly be true. The same flow has to be achieved either way, and lights will always have some margin of inefficiency in switching. Seems lights will always be strictly worse than roundabouts in this sense. There are also solutions for large vehicles where the center is raised but not impassible.
    • pixl97 7mo ago
      You over estimate the intelligence of the average American. I've lived in a few cities with a number of roundabouts and while I love them, the number of stupid people that panic and.. -stop in the roundabout -stop before the roundabout and let their brain buffer for 30 seconds. -somehow go the wrong way in the roundabout -fail to yield to traffic in the roundabout Is way too damn high. It makes traversing one a high stress situation since you have no idea if grandpa grunt and run in to you is about to perform a confusion based terror attack on the traffic control device.
      • t1234s 7mo ago
        LOL.. stop before the roundabout and let their brain buffer for 30 seconds
      • db48x 7mo ago
        Many areas in the USA actually have lots of roundabouts, and people there have figured them out just fine.
        • 7mo ago
• snarf21 7mo ago
  Space/land; you have to displace and buy the four corner properties (at least) to put one in.
• wffurr 7mo ago
  Come to Massachusetts, we have a lot of roundabouts and even a few old style two lane rotaries.
  • t1234s 7mo ago
    I've driven them.. fantastic and no technology to go wrong.
• toast0 7mo ago
  A perpendicular intersection uses way less area than a roundabout. That's the basic reason. Roundabouts have better throughput than a busy 4-way stop, but less throughput than a signaled intersection if the timing and sensing is reasonable (many signaled intersections don't have reasonable sensing). Roundabouts also have some pretty nasty worst case wait times; I'm really not looking forward to the state installing one near me on the approach to a car ferry; it won't be fun to wait for 200 cars to go by before you get a turn to go, and I expect long ferry lines to result in impatient people in the ferry line blocking the roundabout. Sometimes there's two hours between ferry loadings. Going to be some fun times. Personally, I find it challenging to both look ahead to the right to confirm I have room to enter the roundabout, look to the left to confirm there is no traffic that I need to wait for, as well as looking far left and right to ensure there are no pedestrians crossing soon. Signaled 4-way perpendicular intersections have worse outcomes when a participant doesn't follow the signalling, but indication of right of way makes it easier to confirm at a glance if it's safe to proceed.
  • db48x 7mo ago
    > A perpendicular intersection uses way less area than a roundabout. That’s not actually true. It’s entirely possible for them to have the same footprint.
    • unselect5917 7mo ago
      Nitpicking: roundabouts that small may be entirely impassible to truck hauling a standard trailer. Personally, I think we could replace a LOT of stoplights with roundabouts. Way better throughput and faster travel for everyone.
      • db48x 7mo ago
        Roundabouts that small won’t be built in areas with heavy truck traffic, and in any case won’t be built with a raised island in the center.
• db48x 7mo ago
  As with most things, it’s just history. Roundabouts were invented here in the US, but the inventor made a tiny but critical mistake. Originally drivers inside the roundabout had to yield to drivers entering it. Obviously we know now that this leads inevitably to gridlock during heavy traffic, but back then it wasn’t so obvious. The result is that roundabouts were written off as a bad idea, and signalized intersections (also invented around the same time) took off instead.