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The impact of "Roundabouts"

Discussion in 'Cars and Transportation' started by pete8314, Sep 26, 2014.

  1. pete8314

    pete8314 Vendor

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    Roundabouts rock, when used correctly...bit of an alien concept round these parts though.
     
  2. mknox

    mknox Well-Known Member

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    I think the Google maps are, but the navigation maps are stored locally. Some of the new roundabouts that I mentioned in my post above do show up on the Google map, but the navigation map on the dash display (and corresponding audio prompts) still shows the old traditional intersection.

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    On roads with lower traffic volumes they work okay, but there are several higher volume 2 lane in each direction roads where there are now much longer backups entering the roundabout that there ever used to be at a red light. I also understand there are many more accidents in roundabouts, but they are usually less serious ones where a car bumps sideways into another as opposed to the catastrophic t-bone accidents that can happen at intersections. I heard somewhere that the supposed carbon and emission reductions associated with keeping traffic flowing are actually more than offset by the resulting increase in body shop work due to these minor bumps and bangs. Something to do with the painting process IIRC.
     
  3. pete8314

    pete8314 Vendor

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    I come from the land of roundabouts. I've seen very few sideways bumps, but there's a lot more read-end bumps, where the car behind expects you to go, so they're busy looking left (UK) to see if they can go, and they they're in your trunk/boot. Happened to me a couple of times, hesitation will wreck your car. They can work really well on busy streets though, and beat the heck out of sitting at a 4-way stop light for 5 minutes. I used to navigate this baby every day for many years:

    hangar lane.jpg

    Technically a gyratory, so it's one big roundabout with lots of little roundabout surrounding it, giving the option of going clockwise or anticlockwise, depending on your preference/mood/road conditions. If there was one thing I could change about driving in the US, it would be the introduction of proper roundabouts (not the nanny-roundabout that are popping up), and going back to the UK, a right-turn on red (except it would be left, over there).
     
  4. bollar

    bollar Disgruntled Member

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    Texas roundabouts are an abomination, and pete8314, I'm surprised you didn't get wiped out on the ones you would have had to navigate to get to my place. [Heck, I'm surprised I don't get wiped out when I leave the house...]

    The only thing I can think of that's worse is the multilane four-way stop.
     
  5. pete8314

    pete8314 Vendor

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    Ha! Roundabouts work really well when everyone knows what's up. In Texas, they do not, so they get modified to make them idiot proof, except they're not.
     
  6. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    Idiot proofing only deals with one and two sigma idiots. Unfortunately, there are many three through seven sigma idiots.
     
  7. ZBB

    ZBB Emperor

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    Agree completely. We've had a few put in here lately, including a dual lane one put in a couple blocks from Tesla Service. I'm amazed that people don't understand how to use them -- a guy almost took me out by crossing over from the outer to inner lane (basically he went straight instead of around the round-about). I was in the inner lane and had to brake to avoid him hitting me.

    I've driven a bunch in Europe and loved the roundabouts (especially in the Netherlands and UK...) -- traffic flow was so much smoother than stoplights. The first day or so of driving in the UK was strange due to RHD and driving on the left side of the road -- and looking right and then veering left at a roundabout took a bit of re-learning. But I quickly got used to the opposite direction flow...
     
  8. brianman

    brianman Burrito Founder

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    Hate roundabouts. Especially the ones that have obscured visibility due to planting trees in them -- like they've done this year in the Seattle area.

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    And there's the rub. In software, if someone defends a design decision with "good developers will..." I stop them immediately. "You're writing your code so that an intern that was hired two days ago can change the code within a week."

    Assuming the average driver "knows what's up" when designing your traffic object/obstacle is a mistake. Design for the idiot not the "knows what's up" driver. I'm frankly amazed that 5 way intersections exist at all for similar reasons.
     
  9. Zextraterrestrial

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    that is like saying I hate EVs (ok, totally different but similar :tongue:)

    .you realize the obscured visibility is a proper design feature for roundabouts?

    Roundabouts that you can see straight through are wrong. The median should be high enough that you don't see the cars approaching the other side, you just need to be able to see the cars coming from the left. they are much more efficient than stop controlled intersections with the appropriate mix of approaching traffic volumes. Driving electric through a roundabout vs a stop is much better when they are designed properly and drivers aren't stupid(tough)
     
  10. brianman

    brianman Burrito Founder

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    I don't care if it's "proper design". I consider it unsafe. Obscured visibility is a bad design feature for traffic areas.

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    Yah, I just don't agree on that philosophy. Cars "coming from the left" often start out as "cars approaching [from] the other side". This is a unique characteristic that roundabouts are adding to the equation. So basically they introduce a new problem and then it's "proper design" to make that problem worse? Sounds like government.
     
  11. mknox

    mknox Well-Known Member

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    A problem in my neck of the woods is that the multi-lane roundabouts here are not big enough to support 18-wheelers which frequently have to navigate them. They need both lanes while in the circle and still often run their rear wheels up on the curb. If you're in a car next to one of these going through, you'd better stop or get squeezed out.
     
  12. Larry93428

    Larry93428 Member

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    The ones I am familiar with are too tight. That, the lack of familiarity, and the tendency of some to bully on through makes the roundabout a hazard.
    Back to the drawing board; there must be something better.
     
  13. Peter_M

    Peter_M Member

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    I think roundabouts are great on moderate-traffic roads, and it doesn't take long for drivers to get used to them. Accidents are few and minor from what I've seen and there's less waiting/idling. In moderate to heavy traffic, traffic moves along continuously and in light traffic you almost never have to stop.

    This one
    near me replaced a 4-way stop that was congested every day and I've never seen congestion there since. And this one is multi-lane but also seems to work well. The "sidewalk" around the centre median has a low, sloped curb to allow buses and trucks to ride over it if necessary.

    One downside vs. traffic lights is that the traffic leaving the intersection is no longer "bunched" when it's busy, making it hard to turn onto the road from driveways and small side-streets (especially turning left).
     
  14. stevezzzz

    stevezzzz R;SigS;P85D;SigX

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    I like roundabouts in countries where drivers grow up with them: the rules are simple and when everybody knows them, traffic flows smoothly. But in the USA, not enough drivers understand how they're supposed to behave at a roundabout and there hasn't been a concerted effort by government to get the word out on the rules of engagement (sic). The result is mass confusion and then you get people throwing up their hands and complaining about how they hate roundabouts.

    So, as a public service, here are the rules: 1) when entering a roundabout you must yield the right of way to any vehicle present in the roundabout; 2) once in the roundabout, use your turn signal ONLY to indicate your intention to leave the roundabout at the next exit.

    The beauty of a roundabout when compared to a four-way stop is that there is no ambiguity in Rule 1: a vehicle established in the roundabout always has the right of way, either to continue or to exit, over a vehicle approaching the roundabout. There is never a question as to who was there first, as there inevitably is at a four-way stop...and you don't have to solve the conundrum of the 'rolling stop', or the 'dance to the scene of the accident' you often get when two drivers both assume they have the right of way to proceed through the intersection.
     
  15. astrotoy

    astrotoy Member

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    I saw an episode of 'Mythbusters' where they tested a roundabout versus a four way stop sign. In the test, the roundabout was more efficient (higher traffic flow). My first encounter with roundabouts was driving near Cambridge, UK back in 1965. My family had bought a Mercedes 230 to bring back to the states after my father's sabbatical, so it was left hand drive. There wasn't any traffic and I went around two roundabouts driving to the right and only realized I was going the wrong way when a car appeared approaching from the other direction and he went to my right - fortunately enough far in front of me that I correctly turned to the left.
     
  16. brianman

    brianman Burrito Founder

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    It might be fun (though unhealthy for you and vehicle) to just stay in the roundabout for about 50 cycles -- and record the "fun" with your dashcam.
     
  17. ZBB

    ZBB Emperor

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    That "fun" is called a "skidpad" :wink:
     
  18. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

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    That's actually often the point. By reducing visibility people perceive it as less safe, which means they in turn take more care. There's a famous case in The Netherlands where removal of road markings at a black-spot intersection dramatically reduced accidents for cars, bicycles and pedestrians.

    Why do you need to know that there's a car on the other side of the roundabout? There's only one reason I can think of, and that's if you're trying to avoid slowing down for the roundabout (which, as a hypermiler , I can understand). But if a traffic engineer is deliberately wanting to make people slow down they can limit visibility to match desired speed.

    If you would like the trees to be removed, see if you can get hold of traffic and accident data so you can show that it's become more dangerous.
     
  19. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

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    What has made things worse in the past is that US states have different laws for roundabout priority and that design sucked. (BTW, I hate SwiftKey autocorrect, but I like the thumb keyboard.) Modern design key was to change the angle of entry to maximize visibility and size the roundabout appropriately. One rotary in Augusta, ME was turned into a proper rotary, which was great, but unfortunately there's not really enough room so outer entry visibility can often be blocked by taller vehicles so you either wait or hide behind it.

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    There's also a problem if there's a dominant flow, where others can't get a lookin. Both can be helped with traffic lights used during high volume periods.
     
  20. pete8314

    pete8314 Vendor

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    The other rule is you only take the inside lane if you're taking the last exit, and you indicate accordingly. There is a downside to roundabouts, as anyone that's driven through Milton Keynes will know (MK is one of the so-called 'New Towns', which was loosely built using the concept of city blocks). That was the first and only time I experienced brake-fade when driving on regular roads, as the town is threaded with artery roads (dual carriageway, 70mph), but there's a roundabout every half a mile.

    You're right though, being familiar with roundabout rules helps, my office used to be near Heathrow, and you really would take your life into your own hands if you shortcut through the airport and past the rental parking lots.
     

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