There’s a major roundabout near my parents’ house, where they only halfway applied this solution, and it leads to a mess.
It’s on a four-lane road, which was moderately busy in the past, but which has become very busy over the last decade, due to a bunch of new retail and restaurants being built along it.
The roundabout is about 300 yards north of a highway interchange; there are stoplights on the road on either side of the interchange (controlling the entrance/exit ramps), and another stoplight about 500 yards further south.
During afternoon rush hour (yes, Green Bay actually has a rush hour ), southbound traffic on that road backs up massively, due to the stoplights, to the point that stopped/waiting traffic backs up into, and past, the big roundabout. Any other time of day, it’s not bad, but it’s an area that I avoid like the plague in late afternoon.
Yes, I did forget to mention that in order for this solution to work, you have to eliminate all the traffic lights. If you leave any in there then it disrupts the traffic flow, and traffic goes back to the “platoon” flow, and it leads to the mess you described.
This is the main reason the city of Boulder, Co started installing roundabouts a few decades ago. Their biggest issue was, and still is, that there are few non-neighborhood options for east/west travel in the city. Instead of optimizing the existing main roads so drivers will prefer them, the plan was (and is) to make driving more annoying, so people will get out of their cars.
The bit of irony is that the traffic-calming roundabouts are more efficient than the previous 2- and 4-way stop sign controlled intersections they replaced, making the neighborhood routes better for driving. I think they do manage to keep people’s speeds down, which was one of the goals.
As far as I’m aware, the big objection that the roundabouts would make it impossible for large emergency vehicles to quickly access those neighborhoods never happened. Mostly because even when going full lights and siren, I doubt a firetruck is going to be driving much faster than the speed limit on these 25MPH streets.
The majority of my roundabout experiences have been in New Zealand and Australia, which meant driving on the “wrong” side of the road. I got used to them after a fashion but even after a couple of weeks I still approached them with some anxiety. My last trip I only got honked at 5 or 6 times.
I’ve talked about this before on YouTube and people thought I was being a troll. In my opinion roundabouts are the worst thing ever invented. They’re confusing and slow traffic. If you want proof, you’ll hardly find anyone who has anything nice to say about Washington DC traffic.
The terms tend to get used interchangeably, IME, and I didn’t realize that there was a difference, either, until a few years ago (probably pointed out by someone here on the SDMB).
There’s a circle four blocks from my house, which is nicknamed “Eight Corners,” as four streets (a N-S, an E-W, a NW-SE, and a NE-SW) all converge there. It’s absolutely a traffic circle, as the inflowing streets hit the circle at a 90-degree angle (as per the left-side picture in @Q.Q.Switcheroo 's link), with stop signs where each street intersects with the circle.
I did not realize that the Federal Highway Administration recognizes different forms of circular intersections under different names, and roundabouts are similar to but different from traffic circles.
Great cite there @ricepad! Although I bet there are a lot of folk taxonomies out there that define “traffic circle”, roundabout", and “rotary” differently than DoT does.
I have to say that IME the useability of circular intersections regardless of terminology declines as the number of lanes increase. One lane = easy; two lanes = challenging; 3+ lanes = fender bender Central.
I am going to fight you on both of these contentions.
The car on the right had the right of way. Huh? I don’t even know where you are getting this from. Unless you are talking about if both vehicles arrive at the intersection at the same time, then the one on the right proceeds first. If that is what you are referring to, then see point 2:
The car that got to the intersection first had the right of way. This is still the case with the roundabout. the car that is already circling when you arrive to the roundabout does, indeed, have the right of way.
But as to #2, the common POV of the untrained driver is not that it’s who got to the overall roundabout first that determines right of way. But rather who will get to any particular entry point first, whether arriving from a radial road or by circulating around the roundabout to it.
So If I’m on a radial road heading towards a roundabout and I see someone circulating and I calculate I’ll get to the point of collision before they do, I have the right of way. I’ll be there first, and furthermore I’ll be on the right. So the circulator should slow and give way to me as I enter.
Now the above is legally wrong. But it’s logical and consistent with all non-roundabout driving experience. So that’s what drivers typically think until they’re retrained otherwise, or are confronted with a stop or yield sign at the radial’s entrance to the circulator to override their mistaken notion of right of way at an otherwise uncontrolled intersection.
Said another way, untrained inexperienced people tend to think of a roundabout as 4 separate uncontrolled T intersections.
Yes, acquisition of additional land for the right-of-way generally exceeds costs of creating signalized intersections. Understand that installation of roundabouts is typically initiated as a reaction to traffic management challenges and associated negative impacts. This means the intersection is typically already in existence and needs to be redesigned. These intersections are often in fairly well-developed areas when the need is first identified. Municipalities can acquire the land necessary through the process of eminent domain. However, any lands thus acquired must be paid “just compensation” which usually means fair market value. Municipalities tend (but not always) to err on the side of being generous when acquiring land through eminent domain. As mentioned previously roundabouts are often constructed in well developed areas. Developed land tends to command premium property values, and consequently the costs can very quickly escalate.
If you don’t mind, could you tell me where this was.
I don’t have an FB account and I could see the comments just fine. There are limits to what I can do, but it’s not totally shut off.
More likely that it’s an old circular intersection. They didn’t always have the yield-to-traffic-in-the-circle rule. That wasn’t invented until about 1966.
This is probably just a traffic calming circle, not a roundabout. Those are mainly to slow traffic because people were speeding through the residential area.
You want extreme examples, try googling for >> 100 mph roundabout <<. There have been a few times when someone has hit one at that speed. The one I’m familiar with was in the desert in southern California, but I saw some links to at least one other.
There are relatively few roundabouts in San Francisco, and I can’t recall any that had that kind of signage. I recall seeing some that were signed that way in the Palm Springs area.
), southbound traffic on that road backs up massively, due to the stoplights, to the point that stopped/waiting traffic backs up into, and past, the big roundabout. Any other time of day, it’s not bad, but it’s an area that I avoid like the plague in late afternoon.