Two lane exit from single lane

[jeffandnicole]

Why more circles aren't re-striped as roundabouts, I couldn't say. It genuinely boggles my mind. There are obviously many that have been re-striped, but the fact that there are circles with concentric markings still out there, really surprises me. We've been building modern roundabouts for over 20 years at this point.

Markings?  We don't need no stinkin markings.

This is a 2 lane circle throughout:  https://goo.gl/maps/eWrSDzh3DJs  It's only marked in two spots, and that's only to show where traffic is supposed to yield within the circle.

[jakeroot]

The European rules generally discount the first exit (most often, a right turn). Both lanes can proceed past this exit, but at the next exit, the right lane becomes an exit only.

Thing is, exit only to which lane? You'll often have conflicts here between motorists exiting from the right lane of the circle and from the left lane of the circle, both into the left lane of the exit. Given the way it's striped, why shouldn't someone in the right lane of the circle expect to have both exiting lanes available to him?

You exit into the lane that you're in within the circle. For example, if you're in the right lane, you exit into the right lane. If you're in the left lane, you exit into the left lane (or continue around the circle). The way it's striped is definitely misleading. But the markings are only meant to delineate lanes within the circle (i.e. to prevent side-swipes), not to help traffic exit the circle.

(There's a lot more at play here, too, such as the toll booth to the bridge requiring a choice between staffed (right) and E-ZPass (left) lanes. Plus the fact that the circle is often just plain jammed up with traffic, such that any roundabout functionality goes out the window...)

They wouldn't jam up as much, if there were more rules. Higher lane utilization = higher throughput = less jams.

Why more circles aren't re-striped as roundabouts, I couldn't say. It genuinely boggles my mind. There are obviously many that have been re-striped, but the fact that there are circles with concentric markings still out there, really surprises me. We've been building modern roundabouts for over 20 years at this point.

Markings?  We don't need no stinkin markings.

This is a 2 lane circle throughout:  https://goo.gl/maps/eWrSDzh3DJs  It's only marked in two spots, and that's only to show where traffic is supposed to yield within the circle.

They should at least put some left/right/straight arrows at the entry legs, so each lane knows what it can do. And maybe move the yield lines to the entry legs.

[empirestate]

The European rules generally discount the first exit (most often, a right turn). Both lanes can proceed past this exit, but at the next exit, the right lane becomes an exit only.

Thing is, exit only to which lane? You'll often have conflicts here between motorists exiting from the right lane of the circle and from the left lane of the circle, both into the left lane of the exit. Given the way it's striped, why shouldn't someone in the right lane of the circle expect to have both exiting lanes available to him?

You exit into the lane that you're in within the circle. For example, if you're in the right lane, you exit into the right lane. If you're in the left lane, you exit into the left lane (or continue around the circle). The way it's striped is definitely misleading. But the markings are only meant to delineate lanes within the circle (i.e. to prevent side-swipes), not to help traffic exit the circle.

So if you're exiting from left lane to left lane, how do you avoid conflict with someone in the right lane not exiting?


iPhone

[jeffandnicole]

They should at least put some left/right/straight arrows at the entry legs, so each lane knows what it can do. And maybe move the yield lines to the entry legs.

Ah, then it wouldn't be a Jersey traffic circle!

Most of them have functioned in this nature...sometimes the entry yields, sometimes those within the circle yields, and sometimes there is no control.  Generally, the movements with the heaviest traffic flow have the right of way.  It's been like this for decades...it's not going to change.  Compared to some of them, this one actually has a fair amount of lane control.

That all said, the circle is undergoing some reconstruction: There's a small, heavily used side road (Creek Road) just south of the circle.  They're eliminating most movements to/from this road from the circle as turning vehicles from the circle have a habit of blocking the entire road.  They'll reconstruct other portions of the circle to provide more room.  But it will still be a Jersey traffic circle with Jersey traffic circle features when construction is completed.

[jakeroot]

The European rules generally discount the first exit (most often, a right turn). Both lanes can proceed past this exit, but at the next exit, the right lane becomes an exit only.

Thing is, exit only to which lane? You'll often have conflicts here between motorists exiting from the right lane of the circle and from the left lane of the circle, both into the left lane of the exit. Given the way it's striped, why shouldn't someone in the right lane of the circle expect to have both exiting lanes available to him?

You exit into the lane that you're in within the circle. For example, if you're in the right lane, you exit into the right lane. If you're in the left lane, you exit into the left lane (or continue around the circle). The way it's striped is definitely misleading. But the markings are only meant to delineate lanes within the circle (i.e. to prevent side-swipes), not to help traffic exit the circle.

So if you're exiting from left lane to left lane, how do you avoid conflict with someone in the right lane not exiting?

The person in the right lane must exit. If there's a conflict, it's because the person in the right lane incorrectly continued around the circle.

To make it clearer (hopefully), the right lane cannot go more than 180-degrees around the circle. If you plan on going more than 180 degrees around the circle, use the left lane. If you plan on going less than 180 degrees around the circle, use the right lane. If you plan on going exactly 180 degrees through the circle, use either lane (if applicable), but exit into the lane that you were in while within the circle.

Here's a diagram. You can see that, in no scenario, does the right lane ever continue more than 180 degrees around the circle. What you do at each "node" is dependent on where you entered.

I can do more of these diagrams if you want. They don't take me long.

[empirestate]

OK, so if I'm in the left pink entrance lane destined for the left blue exit lane, I'm in conflict with the right yellow entrance lane if he's going 180 around the circle. In a properly-striped roundabout, my path would shunt over and merge with his entrance path. But in this case it doesn't; I'm still in the left lane and cutting across his right lane.



iPhone

[vdeane]

Around here, our multilane roundabouts say "yield to all lanes in circle" for that reason.  Multilane modern roundabouts use the European rules, but traffic circles are ambiguous, so you could have the situation where the left lane is in conflict with the right there.

[kphoger]

Both lanes can proceed past this exit, but at the next exit, the right lane becomes an exit only.

The person in the right lane must exit. If there's a conflict, it's because the person in the right lane incorrectly continued around the circle.

These two statements are contradictory.  If I am in the left lane, intending to proceed straight through the roundabout, then my path conflicts with a driver entering from my right using the right lane and intending to proceed straight through the roundabout.  Photobucket is being stupid right now, so I can't post the illustration I made.

[jakeroot]

OK, so if I'm in the left pink entrance lane destined for the left blue exit lane, I'm in conflict with the right yellow entrance lane if he's going 180 around the circle. In a properly-striped roundabout, my path would shunt over and merge with his entrance path. But in this case it doesn't; I'm still in the left lane and cutting across his right lane.

See my response below. It may answer this concern.

[click link above for original quote]

These two statements are contradictory.  If I am in the left lane, intending to proceed straight through the roundabout, then my path conflicts with a driver entering from my right using the right lane and intending to proceed straight through the roundabout.  Photobucket is being stupid right now, so I can't post the illustration I made.

What you do at each node is dependent on where you entered, and is the reason why spiral markings are now preferred. Ideally, avoid driving next to someone who merged from an entry leg other than your own, because at each node, there'd be a conflict between drivers who are, in their head, going straight, and other drivers who are, in their head, going left.

To say this is hard to explain would be an understatement.

[johndoe]

Let's see if I can summarize the four pages of this thread:  Every diverge should be striped to allow, at max, one driver to make a choice.   

[kphoger]

OK, so if I'm in the left pink entrance lane destined for the left blue exit lane, I'm in conflict with the right yellow entrance lane if he's going 180 around the circle. In a properly-striped roundabout, my path would shunt over and merge with his entrance path. But in this case it doesn't; I'm still in the left lane and cutting across his right lane.

See my response below. It may answer this concern.

[click link above for original quote]

These two statements are contradictory.  If I am in the left lane, intending to proceed straight through the roundabout, then my path conflicts with a driver entering from my right using the right lane and intending to proceed straight through the roundabout.  Photobucket is being stupid right now, so I can't post the illustration I made.

What you do at each node is dependent on where you entered, and is the reason why spiral markings are now preferred. Ideally, avoid driving next to someone who merged from an entry leg other than your own, because at each node, there'd be a conflict between drivers who are, in their head, going straight, and other drivers who are, in their head, going left.

To say this is hard to explain would be an understatement.

OK, I'm back home again and Photobucket is cooperating.  Here is my illustration.  If I am following the red path, then I conflict with a car following the blue path at my point of exit.  To say that I should avoid driving next to that blue-path car doesn't help at all, because that car doesn't enter the roundabout until I'm already committed to exiting.





This thread has gotten off topic by now, but it has somehow managed to fit quite nicely into the 'crash-prone modern roundabouts' discussion–i.e., what it is about multi-lane roundabouts that can lead to accidents.

[Ned Weasel]

OK, I'm back home again and Photobucket is cooperating.  Here is my illustration.  If I am following the red path, then I conflict with a car following the blue path at my point of exit.  To say that I should avoid driving next to that blue-path car doesn't help at all, because that car doesn't enter the roundabout until I'm already committed to exiting.

If it's a standard roundabout, then everyone is required to yield upon entry to the roundabout.  This means the blue car was required to yield to all traffic already in the roundabout, meaning the blue car was required to yield to the red car.

[empirestate]

OK, I'm back home again and Photobucket is cooperating.  Here is my illustration.  If I am following the red path, then I conflict with a car following the blue path at my point of exit.  To say that I should avoid driving next to that blue-path car doesn't help at all, because that car doesn't enter the roundabout until I'm already committed to exiting.

If it's a standard roundabout, then everyone is required to yield upon entry to the roundabout.  This means the blue car was required to yield to all traffic already in the roundabout, meaning the blue car was required to yield to the red car.

Ah, well that's the whole issue–it isn't a standard roundabout. (Here again is a link to the one in question.)

In our case, the red car is in the left lane of the circle, which is just striped to be concentric to the central island. Cars can change lanes into and out of it, but there's no visual indication that the left lane offers an exit to the left lane of the leg of the intersection. However, when I pondered what the left lane's purpose was, it was suggested that it is indeed intended to function this way. This leads to conflicts between exiting traffic in the left lane of the circle, and traffic entering its right lane.

(Also, the blue car doesn't have to be traveling through the circle to pose a conflict. It could also be entering from the right lane but taking the left lane of the first exit.)

[jeffandnicole]

OK, I'm back home again and Photobucket is cooperating.  Here is my illustration.  If I am following the red path, then I conflict with a car following the blue path at my point of exit.  To say that I should avoid driving next to that blue-path car doesn't help at all, because that car doesn't enter the roundabout until I'm already committed to exiting.

If it's a standard roundabout, then everyone is required to yield upon entry to the roundabout.  This means the blue car was required to yield to all traffic already in the roundabout, meaning the blue car was required to yield to the red car.

That statement would mean that only one car would be permitted in a roundabout at one time, which is by far not the objective of a roundabout, and would lead to significant congestion.

A car in the right lane, pulling into the right lane, only should need to worry about the right lane. 

[jakeroot]

OK, I'm back home again and Photobucket is cooperating.  Here is my illustration.  If I am following the red path, then I conflict with a car following the blue path at my point of exit.  To say that I should avoid driving next to that blue-path car doesn't help at all, because that car doesn't enter the roundabout until I'm already committed to exiting.

If it's a standard roundabout, then everyone is required to yield upon entry to the roundabout.  This means the blue car was required to yield to all traffic already in the roundabout, meaning the blue car was required to yield to the red car.

That statement would mean that only one car would be permitted in a roundabout at one time, which is by far not the objective of a roundabout, and would lead to significant congestion.

A car in the right lane, pulling into the right lane, only should need to worry about the right lane.

That's true in theory. But in practice, there's lots of spiralling that occurs within roundabouts. It's not always a safe to merge into a roundabout right next to someone else. 

[kphoger]

empirestate
To me, the question of how striping should be done is a different (though related) topic from what people should and shouldn't do from a given lane.  After all, I don't know how the circulating roadway of a multi-lane roundabout is striped upon approach; I choose my lane before I ever get to that point, based on my intended path.

jeffandnicle
That may be overstating things.  There's a big difference between saying an approaching driver must yield to everyone in the roundabout and saying an approaching driver must wait for all traffic to completely clear the roundabout before entering.  It might be fair to say the blue driver must yield to the red driver if their paths might conflict, or it might be fair to say there's an inherent problem in the design.

[jeffandnicole]

jeffandnicle
That may be overstating things.  There's a big difference between saying an approaching driver must yield to everyone in the roundabout and saying an approaching driver must wait for all traffic to completely clear the roundabout before entering.  It might be fair to say the blue driver must yield to the red driver if their paths might conflict, or it might be fair to say there's an inherent problem in the design.

I simply responded to the message above mine: "This means the blue car was required to yield to all traffic already in the roundabout"

[Ned Weasel]

I simply responded to the message above mine: "This means the blue car was required to yield to all traffic already in the roundabout"

I meant "yield" as in giving the other cars precedence at conflict points, not waiting for all traffic inside the roundabout to go away.  My understanding of roundabout rules has always been that traffic entering a roundabout yields to traffic inside the roundabout when their paths conflict.

Ah, well that's the whole issue–it isn't a standard roundabout. (Here again is a link to the one in question.)

In our case, the red car is in the left lane of the circle, which is just striped to be concentric to the central island. Cars can change lanes into and out of it, but there's no visual indication that the left lane offers an exit to the left lane of the leg of the intersection. However, when I pondered what the left lane's purpose was, it was suggested that it is indeed intended to function this way. This leads to conflicts between exiting traffic in the left lane of the circle, and traffic entering its right lane.

(Also, the blue car doesn't have to be traveling through the circle to pose a conflict. It could also be entering from the right lane but taking the left lane of the first exit.)

Judging solely by the rule of who yields to whom, it's a standard roundabout.  Judging by striping, suffice it to say that I'd agree that the striping in that example is confusing, and I believe the striping in kphoger's diagram is preferable.

[empirestate]

empirestate
To me, the question of how striping should be done is a different (though related) topic from what people should and shouldn't do from a given lane.  After all, I don't know how the circulating roadway of a multi-lane roundabout is striped upon approach; I choose my lane before I ever get to that point, based on my intended path.

To me as well. To be sure, better signage of the options approaching this roundabout would help, particularly as it pertains to which exit lane at the tollboth is E-ZPass only, and which is staffed. But my ponderance was based solely on the way it is actually striped, and how that suggests the inner lane of the circle is meant to be used. Or, for that matter, the outer lane, since the way it's striped suggests that someone in that lane could continue around the circle indefinitely; it never guides you to either (and only) the first or second exit, as a proper roundabout would.

[slorydn1]

Well, I think the only thing I now understand about roundabouts after this last page or so is the reason why so many people despise them so much.

At least at an admittedly less efficient 4 way intersection with traffic control devices in place its not hard to tell who should be doing what in each lane of the intersection. Fool Proof? No, and the thousands of intersection crashes every year attest to that, but at least when the dust settles, it's pretty easy to figure out who screwed up.

I have always been ambivalent about roundabouts. I like them for their efficiency but hate them for the fact that if the members of a road related forum can't agree on how to use them, how in the hell can we expect little Ms Soccermom who is barely able to pay attention to the road with a van full of screaming kids to figure out how to use them? Which lane to be in, who has the right of away, oh GOD why is this idiot in front of me slamming on the brakes we don't have to stop?!?!

[Brandon]

OK, I'm back home again and Photobucket is cooperating.  Here is my illustration.  If I am following the red path, then I conflict with a car following the blue path at my point of exit.  To say that I should avoid driving next to that blue-path car doesn't help at all, because that car doesn't enter the roundabout until I'm already committed to exiting.

If it's a standard roundabout, then everyone is required to yield upon entry to the roundabout.  This means the blue car was required to yield to all traffic already in the roundabout, meaning the blue car was required to yield to the red car.

That statement would mean that only one car would be permitted in a roundabout at one time, which is by far not the objective of a roundabout, and would lead to significant congestion.

A car in the right lane, pulling into the right lane, only should need to worry about the right lane. 

That kind of activity should get you the horn.  You pull out only when ALL lanes are clear.  Otherwise, you are at fault for that crash, and will get the ticket assigned to you.

[jeffandnicole]

OK, I'm back home again and Photobucket is cooperating.  Here is my illustration.  If I am following the red path, then I conflict with a car following the blue path at my point of exit.  To say that I should avoid driving next to that blue-path car doesn't help at all, because that car doesn't enter the roundabout until I'm already committed to exiting.

If it's a standard roundabout, then everyone is required to yield upon entry to the roundabout.  This means the blue car was required to yield to all traffic already in the roundabout, meaning the blue car was required to yield to the red car.

That statement would mean that only one car would be permitted in a roundabout at one time, which is by far not the objective of a roundabout, and would lead to significant congestion.

A car in the right lane, pulling into the right lane, only should need to worry about the right lane. 

That kind of activity should get you the horn.  You pull out only when ALL lanes are clear.  Otherwise, you are at fault for that crash, and will get the ticket assigned to you.

How come?  I'm pulling out from the right lane to the right lane.  I'm not impacting the vehicle in the left lane. 

Please state the statute number that I have violated by doing the above.

[empirestate]

Well, I think the only thing I now understand about roundabouts after this last page or so is the reason why so many people despise them so much.

Meaning, people despise modern roundabouts because of the uncertainty surrounding old-fashioned traffic circles?

I have always been ambivalent about roundabouts. I like them for their efficiency but hate them for the fact that if the members of a road related forum can't agree on how to use them, how in the hell can we expect little Ms Soccermom who is barely able to pay attention to the road with a van full of screaming kids to figure out how to use them? Which lane to be in, who has the right of away, oh GOD why is this idiot in front of me slamming on the brakes we don't have to stop?!?!

I don't think we (forum members) have any trouble figuring out how to use roundabouts; the confusion in recent posts has been about whether and how to apply the lane assignment conventions of modern roundabouts to an older installation whose lane markings don't match that usage.

You're quite right, though, that the average motorist tends to find them confusing. The biggest hang-up I normally see is that people stop on the approach when there is no traffic in the circle, which reduces the efficiency of the design. Honestly, in my area it's not a major delay at all, but being this close to NYC/NJ/CT, it's just frustrating that the one and only time you can always count on people to observe a stop or yield sign is when they don't even need to!

[Brandon]

OK, I'm back home again and Photobucket is cooperating.  Here is my illustration.  If I am following the red path, then I conflict with a car following the blue path at my point of exit.  To say that I should avoid driving next to that blue-path car doesn't help at all, because that car doesn't enter the roundabout until I'm already committed to exiting.

If it's a standard roundabout, then everyone is required to yield upon entry to the roundabout.  This means the blue car was required to yield to all traffic already in the roundabout, meaning the blue car was required to yield to the red car.

That statement would mean that only one car would be permitted in a roundabout at one time, which is by far not the objective of a roundabout, and would lead to significant congestion.

A car in the right lane, pulling into the right lane, only should need to worry about the right lane. 

That kind of activity should get you the horn.  You pull out only when ALL lanes are clear.  Otherwise, you are at fault for that crash, and will get the ticket assigned to you.

How come?  I'm pulling out from the right lane to the right lane.  I'm not impacting the vehicle in the left lane. 

Please state the statute number that I have violated by doing the above.

And should that vehicle in the left lane decides to change lanes, you're the one who will get hit.

[vdeane]

Plus, in a modern roundabout, vehicles don't necessarily STAY in the same lane.  In a properly striped roundabout, the right lane exits off, and the left becomes the right, with a new one forming on the left, often with traffic exiting from the left as well!  If you didn't yield to all lanes, you'd cause an accident.
https://goo.gl/maps/hSLpBVfwNBr