I was talking to an ex truck driver who brought up an interesting point about the roundabouts. How small they are and how more challenging they are for semis to circumvent.
In Hammond, LA you have two roundabouts and a raised curb controlling US 51 Business south of I-12 and that area between the two roundabouts is with two major truck stops. So to patronize either Truck Stop, all traffic must use both roundabouts as the raised curbs eliminates left turns and creates RIRO for the business driveways thus forcing the semis to make 180 degree turns in a small diameter circle.
My question is, have state officials simply ignored the actual situation created by tight roundabouts for maneuverability to large vehicles? Or is that they feel truckers, the back bone of US commerce, are not challenged enough already so making them pay attention more and screw the rest of traffic when they have to slow down to wait patiently for a semi circumventing the roundabout as the geometry of the circle slows down the time it takes to use it for truckers? After all they're the same greedy politicians who allow overdevelopment in rural areas without expanding the highways around it allowing the roundabouts to be norm now.
To me math suggests that the truckers are at their limit using the roundabout supporting the trucker concerns of using them. Plus the ones in Hammond, LA being placed not only for the interchange ramps, but to control movements to the truck stop patrons as well, is totally not taking in the situation that is at hand. That is with the truckers who have to use them and have to drive it with full scrutiny to avoid hopping the curbs etc. After all do most lawmakers really know what their constituents really experience?
Or just, you know, make them big enough (https://goo.gl/maps/GH27vmbNyykHcJkZ7) for trucks (https://goo.gl/maps/VR1ZxDAnkxZe11Cy7).
Quote from: kphoger on April 22, 2022, 10:16:06 AM
Or just, you know, make them big enough (https://goo.gl/maps/GH27vmbNyykHcJkZ7) for trucks (https://goo.gl/maps/VR1ZxDAnkxZe11Cy7).
Second Fruita reference today. Nicely done.
NY requires aprons to accommodate precisely this situation.
Quote from: roadman65 on April 22, 2022, 10:05:35 AM
In Hammond, LA you have two roundabouts and a raised curb controlling US 51 Business south of I-12 and that area between the two roundabouts is with two major truck stops. So to patronize either Truck Stop, all traffic must use both roundabouts as the raised curbs eliminates left turns and creates RIRO for the business driveways thus forcing the semis to make 180 degree turns in a small diameter circle.
I'm looking at GMSV from just this past January and not seeing the roundabouts you're referring to.
Quote from: froggie on April 22, 2022, 10:30:34 AM
Quote from: roadman65 on April 22, 2022, 10:05:35 AM
In Hammond, LA you have two roundabouts and a raised curb controlling US 51 Business south of I-12 and that area between the two roundabouts is with two major truck stops. So to patronize either Truck Stop, all traffic must use both roundabouts as the raised curbs eliminates left turns and creates RIRO for the business driveways thus forcing the semis to make 180 degree turns in a small diameter circle.
I'm looking at GMSV from just this past January and not seeing the roundabouts you're referring to.
https://www.google.com/maps/dir/30.4820483,-90.4589004//@30.4769424,-90.4595573,16.76z/data=!4m2!4m1!3e0!5m1!1e1
All three of those roundabouts have truck aprons. The center islands are not bordered by hard curbs. They also have extra pavement with yellow striping, which allows truckers extra space to navigate the roundabouts.
https://goo.gl/maps/YT86SHpVR2kKtnv98
Okay...I had BUS 51 and mainline 51 switched in my brain.
But, in light of earlier comments, I'm still seeing truck aprons on those roundabouts.
Is it an inconvenience? Perhaps. But this setup should eliminate any problems there were with left turning traffic and crashes. I'm guessing they had a lot of crashes pre-roundabout and determined this was a good solution to that.
Quote from: kphoger on April 22, 2022, 10:45:34 AM
All three of those roundabouts have truck aprons. The center islands are not bordered by hard curbs. They also have extra pavement with yellow striping, which allows truckers extra space to navigate the roundabouts.
https://goo.gl/maps/YT86SHpVR2kKtnv98
And, judging by the width of the tire tracks, it looks like people not driving trucks are taking advantage of the apron, too.
Pros of roundabouts
Fewer crashes
Fewer emissions
Faster
No stopping/starting
Reduced congestion
Not complicated
Cons of roundabouts
God forbid truckers have to go slower for 100 feet
This truck seems to be doing fine.
https://www.google.com/maps/@30.4755345,-90.4574139,3a,90y,120.32h,81.22t/data=!3m7!1e1!3m5!1sdzbHBrwXDd0R8epbv21gug!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DdzbHBrwXDd0R8epbv21gug%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D2.6700442%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
I think trucks can struggle with multi-lane roundabouts however. I have seen a couple of minor accidents here in the Green Bay area where the truck struggled staying in the lane and touched a car in the lane next to them.
Quote from: SEWIGuy on April 22, 2022, 02:00:27 PM
I think trucks can struggle with multi-lane roundabouts however. I have seen a couple of minor accidents here in the Green Bay area where the truck struggled staying in the lane and touched a car in the lane next to them.
I don't know a trucker could possibly stay in one lane through most roundabouts. But that's the same as with 90-degree turns too.
Quote from: SEWIGuy on April 22, 2022, 02:00:27 PM
I think trucks can struggle with multi-lane roundabouts however. I have seen a couple of minor accidents here in the Green Bay area where the truck struggled staying in the lane and touched a car in the lane next to them.
In my area, they recommend that large trucks straddle both lanes entering and through the roundabout with their hazard lights on to prevent any cars from driving alongside in the roundabout.
Quote from: CtrlAltDel on April 22, 2022, 01:56:45 PM
This truck seems to be doing fine.
https://www.google.com/maps/@30.4755345,-90.4574139,3a,90y,120.32h,81.22t/data=!3m7!1e1!3m5!1sdzbHBrwXDd0R8epbv21gug!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DdzbHBrwXDd0R8epbv21gug%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D2.6700442%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
For sure, that truck apron (using Google's distance tool) is around 5.5-6m wide. In my region, we use only 3.0m and that still works okay.
In Wisconsin, state law says trucks have priority over cars in a roundabout, so a car shouldn't have been travelling in the way of the truck.
Wisconsin state laws don't apply in Louisiana. :awesomeface:
Load shifts in roundabouts can lead to big issues:
(https://eh9ti3qk8yf3m8xqr5gt2fp4-wpengine.netdna-ssl.com/wp-content/uploads/2021/03/24404480_web1_copy_210303-ABB-Flipped-semi_1-640x427.jpg)
(https://i.cbc.ca/1.3078224.1431970948!/fileImage/httpImage/roundabout-rollover.jpg)
(https://media.tegna-media.com/assets/WNEP/images/618e0753-82d6-4f64-bae3-d94f50b4fd15/618e0753-82d6-4f64-bae3-d94f50b4fd15_750x422.jpg)
(https://media.ktvb.com/assets/KTVB/images/fd763ff7-b5b5-47d0-b30b-23b906f6ba48/fd763ff7-b5b5-47d0-b30b-23b906f6ba48_1140x641.jpeg)
Load shifts can lead to big issues in a lot of places, not just roundabouts. And their load probably shifted because they were going too fast...that's simply physics. Unless you have proof that they weren't going too fast in your photo examples.
I wish states would consider building interchange roundabouts like this (https://www.google.com/maps/@52.4500988,-1.1910961,246m/data=!3m1!1e3!5m1!1e1) or even this (https://www.google.com/maps/@51.5151728,-2.1213861,765m/data=!3m1!1e3!5m1!1e1).
Quote from: skluth on April 23, 2022, 02:06:06 PM
I wish states would consider building interchange roundabouts like this (https://www.google.com/maps/@52.4500988,-1.1910961,246m/data=!3m1!1e3!5m1!1e1) or even this (https://www.google.com/maps/@51.5151728,-2.1213861,765m/data=!3m1!1e3!5m1!1e1).
There is this one (https://www.google.com/maps/@39.9418757,-86.0187853,310m/data=!3m1!1e3) in Fisher's, Indiana, but they are admittedly thin on the ground.
This one near me: https://goo.gl/maps/Gx8GrwNmaaZ3GUrYA (https://goo.gl/maps/Gx8GrwNmaaZ3GUrYA)
I feel like it's well designed, yet about twice a month there's a truck on it's side on the SB side, because he went in too hot. The slip lane for NB 287, can be easily taken at 55 (at least in my car). The SB leg (which actually turns compass east here) can be safely taken at 30-35. The lance are nice and wide to allow for trucks turning. Speed limit here is 40, 25 in the actual roundabout, going to 65 just to the north of here, and 45 just to highway south of here (compass east)
But yet still, trucks wreck here.
This used to be a simple 'T' intersection, with slip lanes for the right turns, and a traffic light that defaulted to green for SB 287.
Quote from: CtrlAltDel on April 23, 2022, 02:27:38 PM
Quote from: skluth on April 23, 2022, 02:06:06 PM
I wish states would consider building interchange roundabouts like this (https://www.google.com/maps/@52.4500988,-1.1910961,246m/data=!3m1!1e3!5m1!1e1) or even this (https://www.google.com/maps/@51.5151728,-2.1213861,765m/data=!3m1!1e3!5m1!1e1).
Those are "traffic circles" or in New England terminology, rotaries. Very common during the build up of the Boston area expressway network in the fifties. Rte 128 / US 20 was an example of one, it became hairy as traffic loading increased. Some have outlived there usefulness and should have been replaced with full interchanges 45 years ago. Reformatory Circle in Concord, MA as a leading example.
Quote from: Big John on April 22, 2022, 03:34:59 PM
In Wisconsin, state law says trucks have priority over cars in a roundabout, so a car shouldn't have been travelling in the way of the truck.
However, this wouldn't be a widely known state law to most motorists. It does fall under common sense rules though...give a truck a little more space when turning.
Quote from: Rothman on April 22, 2022, 10:29:58 AM
NY requires aprons to accommodate precisely this situation.
Nearly all roundabouts in every state has aprons; they are standard features of a roundabout.
Quote from: DJStephens on April 24, 2022, 10:23:06 AM
Quote from: CtrlAltDel on April 23, 2022, 02:27:38 PM
Quote from: skluth on April 23, 2022, 02:06:06 PM
I wish states would consider building interchange roundabouts like this (https://www.google.com/maps/@52.4500988,-1.1910961,246m/data=!3m1!1e3!5m1!1e1) or even this (https://www.google.com/maps/@51.5151728,-2.1213861,765m/data=!3m1!1e3!5m1!1e1).
Those are "traffic circles" or in New England terminology, rotaries. Very common during the build up of the Boston area expressway network in the fifties. Some have outlived there usefulness and should have been replaced with full interchanges 45 years ago. Reformatory Circle in Concord, MA as a leading example.
Rotaries and traffic circles are not the same, as rotaries follow the traffic rules of roundabouts.
Quote from: Rothman on April 22, 2022, 10:29:58 AM
NY requires aprons to accommodate precisely this situation.
What store sells aprons big enough to go around a truck?
Quote from: Rothman on April 24, 2022, 10:44:25 AM
Quote from: DJStephens on April 24, 2022, 10:23:06 AM
Quote from: CtrlAltDel on April 23, 2022, 02:27:38 PM
Quote from: skluth on April 23, 2022, 02:06:06 PM
I wish states would consider building interchange roundabouts like this (https://www.google.com/maps/@52.4500988,-1.1910961,246m/data=!3m1!1e3!5m1!1e1) or even this (https://www.google.com/maps/@51.5151728,-2.1213861,765m/data=!3m1!1e3!5m1!1e1).
Those are "traffic circles" or in New England terminology, rotaries. Very common during the build up of the Boston area expressway network in the fifties. Some have outlived there usefulness and should have been replaced with full interchanges 45 years ago. Reformatory Circle in Concord, MA as a leading example.
Rotaries and traffic circles are not the same, as rotaries follow the traffic rules of roundabouts.
Are there really enough "Yield to entering traffic" traffic circles remaining for that to be a noteworthy difference? Pretty much every circular intersection that I have seen in this country has entering traffic yielding to circulating traffic.
Sometimes there's "is this a circle or not", such as these:
https://www.google.com/maps/@42.5925842,-70.9637526,15.8z
https://www.google.com/maps/@42.4552291,-71.0899526,18.55z
In both cases, the main road has priority.
Quote from: roadman65 on April 22, 2022, 10:05:35 AM
making them pay attention more and screw the rest of traffic when they have to slow down to wait patiently for a semi circumventing the roundabout as the geometry of the circle slows down the time it takes to use it for truckers
Thats the intention.
Why on earth would you think that "make them pay attention" is a bad thing????
Quote from: Rothman on April 24, 2022, 10:44:25 AMRotaries and traffic circles are not the same, as rotaries follow the traffic rules of roundabouts.
Though the Stanton St Quintin example (M4/A429/A350/B4122) has traffic lights controlling two corners, and so doesn't follow the traffic rules of roundabouts.
The Lutterworth (M1/A4303/A4304) example is very much a roundabout though.
<Removed post from other thread>
Quote from: english si on April 25, 2022, 03:19:47 PM
Quote from: Scott5114 on April 24, 2022, 10:50:55 PMThere is precisely zero reason a freeway should not always have an Interstate shield. Change my mind.
There are good reasons why not to give freeways interstate shields, kphoger gave two, 'too short' is another. Tolls, possibly?
But yes, the onus should be more on the "not everything needs to be an interstate" crowd to explain why a freeway shouldn't be one than the "bring out the blue and red shields" to try and justify interstate status for a freeway that meets the basic criteria of being up to standards and forming a coherent addition to the network.
Wrong thread, |english si|.
Quote from: jakeroot on April 25, 2022, 01:02:51 AM
Are there really enough "Yield to entering traffic" traffic circles remaining for that to be a noteworthy difference? Pretty much every circular intersection that I have seen in this country has entering traffic yielding to circulating traffic.
Depends what region you're in.
Southern Illinois has plenty of non-standard setups:
Stop signs in the middle, but only on two approaches (https://goo.gl/maps/6qdW8cRcqTDLK6U76)
Town square, yield signs in the middle, but only on two approaches (https://goo.gl/maps/2nq9iEXtKMzvJ3PX6)
Town square, no traffic control at all (https://goo.gl/maps/CcHdxHW5E9rRDoAWA) (I once saw I-57 traffic diverted through this; it was... interesting.)
Quote from: kphoger on April 25, 2022, 03:30:57 PM
Quote from: jakeroot on April 25, 2022, 01:02:51 AM
Are there really enough "Yield to entering traffic" traffic circles remaining for that to be a noteworthy difference? Pretty much every circular intersection that I have seen in this country has entering traffic yielding to circulating traffic.
Depends what region you're in.
Southern Illinois has plenty of non-standard setups:
Stop signs in the middle, but only on two approaches (https://goo.gl/maps/6qdW8cRcqTDLK6U76)
Town square, yield signs in the middle, but only on two approaches (https://goo.gl/maps/2nq9iEXtKMzvJ3PX6)
Town square, no traffic control at all (https://goo.gl/maps/CcHdxHW5E9rRDoAWA) (I once saw I-57 traffic diverted through this; it was... interesting.)
These sorts of setups are far and away a minority of circular intersections. Enough so I don't think they even could be called anything besides a town square or something.
Quote from: roadman65 on April 22, 2022, 10:32:23 AM
Quote from: froggie on April 22, 2022, 10:30:34 AM
Quote from: roadman65 on April 22, 2022, 10:05:35 AM
In Hammond, LA you have two roundabouts and a raised curb controlling US 51 Business south of I-12 and that area between the two roundabouts is with two major truck stops. So to patronize either Truck Stop, all traffic must use both roundabouts as the raised curbs eliminates left turns and creates RIRO for the business driveways thus forcing the semis to make 180 degree turns in a small diameter circle.
I'm looking at GMSV from just this past January and not seeing the roundabouts you're referring to.
https://www.google.com/maps/dir/30.4820483,-90.4589004//@30.4769424,-90.4595573,16.76z/data=!4m2!4m1!3e0!5m1!1e1
The fact that about a third of the parking spaces in that Petro require blind-side backing (when you can't pull through from the other spaces) is a much greater concern than the roundabouts, with their generous geometry clearly showing they were engineered for trucks.
Quote from: jakeroot on April 25, 2022, 07:11:26 PM
Quote from: kphoger on April 25, 2022, 03:30:57 PM
Quote from: jakeroot on April 25, 2022, 01:02:51 AM
Are there really enough "Yield to entering traffic" traffic circles remaining for that to be a noteworthy difference? Pretty much every circular intersection that I have seen in this country has entering traffic yielding to circulating traffic.
Depends what region you're in.
Southern Illinois has plenty of non-standard setups:
Stop signs in the middle, but only on two approaches (https://goo.gl/maps/6qdW8cRcqTDLK6U76)
Town square, yield signs in the middle, but only on two approaches (https://goo.gl/maps/2nq9iEXtKMzvJ3PX6)
Town square, no traffic control at all (https://goo.gl/maps/CcHdxHW5E9rRDoAWA) (I once saw I-57 traffic diverted through this; it was... interesting.)
These sorts of setups are far and away a minority of circular intersections. Enough so I don't think they even could be called anything besides a town square or something.
Except for the part where I said "Depends what region you're in". I can't think of a single "modern" roundabout, with yield-on-entry at all approaches, anywhere in southern Illinois.
Well, except for (1)
this six-way monstrosity (https://goo.gl/maps/PNdN6BYdQsPhoKny7) in Zeigler, for which you'd have to ignore the angle parking and the island so big there's a park inside, and (2) the Saint Louis suburbs, such as
this one in Belleville (https://goo.gl/maps/iQpmPewg97SCei76A) that
used to be (https://goo.gl/maps/iu6cGpb8wwsuyn3F8) uncontrolled.
In other words, "these sorts of setups" are actually the majority of circular intersections in southern Illinois.
Quote from: kphoger on April 22, 2022, 10:45:34 AM
All three of those roundabouts have truck aprons. The center islands are not bordered by hard curbs. They also have extra pavement with yellow striping, which allows truckers extra space to navigate the roundabouts.
https://goo.gl/maps/YT86SHpVR2kKtnv98
This wide single lane design might be great. In Texas, they make the same basic roundabout, but they make it two lanes wide.
Those are confusing and they increase the sideswipe incursions.
The ones in Texas are generally not on roads with significant truck traffic.
Quote from: Ned Weasel on April 25, 2022, 10:03:52 PM
Quote from: roadman65 on April 22, 2022, 10:32:23 AM
Quote from: froggie on April 22, 2022, 10:30:34 AM
Quote from: roadman65 on April 22, 2022, 10:05:35 AM
In Hammond, LA you have two roundabouts and a raised curb controlling US 51 Business south of I-12 and that area between the two roundabouts is with two major truck stops. So to patronize either Truck Stop, all traffic must use both roundabouts as the raised curbs eliminates left turns and creates RIRO for the business driveways thus forcing the semis to make 180 degree turns in a small diameter circle.
I'm looking at GMSV from just this past January and not seeing the roundabouts you're referring to.
https://www.google.com/maps/dir/30.4820483,-90.4589004//@30.4769424,-90.4595573,16.76z/data=!4m2!4m1!3e0!5m1!1e1
The fact that about a third of the parking spaces in that Petro require blind-side backing (when you can't pull through from the other spaces) is a much greater concern than the roundabouts, with their generous geometry clearly showing they were engineered for trucks.
Seems normal for Petro and TA truck stops. A lot of drivers don't blind-side back anyway (they turn left while moving forward and then they back straight)