Multi-lane roundabouts

Turtle-TM

Feed Up wrote: »

What are you on about?

If your in lane 2, then in order to exit the R/A you have to enter lane 1 irrespective of the number of lanes on the off ramp. You still have to enter/cross lane 1.

So get into lane 1 (1st manoeuvre) and then exit (2nd manoeuvre) instead of just driving across the lanes and thinking you're in the right. And don't forget to MSMM.

You're wrong I'm afraid. You should not change lanes whilst on a roundabout. If you are in the right lane to take an exit and there is a 2 lane exit you stay in lane.

grogi

Turtle-TM wrote: »

You're wrong I'm afraid. You should not change lanes whilst on a roundabout. If you are in the right lane to take an exit and there is a 2 lane exit you stay in lane.

- We are breaking this broadcast to warn the motorist that on M50 there is a car in wrong lane going againts the traffic... Drivers, be aware...
- A car?! There are hundreds of them!

Jack Killian

grogi wrote: »

This time it is clearly marked with the dashed line how the lane goes. It would be the green that cuts through the lane...

....and everyone in the left lane has to slam on the brakes when a car has to cross, which is exactly the OPPOSITE of what has to happen (or at least, what's supposed to happen) in every other scenario.

Think of what happens at "slow lane" ends, and what's supposed to happen.

In reality, the car on the left has the right of way - the person on the right is not meant to overtake them within the last few metres.

In reality they do, obnoxiously bullying their way past, safe in the knowledge that the timid / slower driver who has been gracious enough to act responsibly is unlikely to risk causing a crash.

So - in lots of cases - they repainted the road markings to emphasise that the car on the right DOES NOT HAVE the right to brazen their way past.

I'm not saying that's what happens on roundabouts, but it would mean that there was suddenly a different rule; and the fact that it's different while not actually solving the issue means that it's dangerous.

Not having a go - it was a decent and genuine effort and I acknowledge and appreciate that; but it's unfortunately not a solution and would - IMHO - be dangerous, with rear-ends in the left lane as a direct result.

At least if the car in the right lane has an indicator on, the following cars should be expecting something; the left-hand car would have none on until AFTER they've passed the exit.

Jack Killian

Turtle-TM wrote: »

You're wrong I'm afraid. You should not change lanes whilst on a roundabout. If you are in the right lane to take an exit and there is a 2 lane exit you stay in lane.

You are still CROSSING a "live" lane in which cars MAY be going straight on. They're in there before you, so they have the right of way, not you.

Jack Killian

grogi wrote: »

Should they wanted to exit to the West, they would need to take the inner lane at entry (I did not update the arrows at entry, so they might be confusing)...

What happens in a scenario where all the exits are two-lane ? This roundabout is pretty specific with no exit to the east and no entrance to the northwest (I'm guessing some sort of a flyover to the north ?)

In fairness you are trying to solve a problem, but it can't be done in broader, more general terms I'm afraid.

It MAY work for flyover on/off ramps (depending on the number of other exits) but - as I said - you've then got variable rules, which is risky.

grogi

Jack Killian wrote: »

....and everyone in the left lane has to slam on the brakes when a car has to cross, which is exactly the OPPOSITE of what has to happen (or at least, what's supposed to happen) in every other scenario.

Think of what happens at "slow lane" ends, and what's supposed to happen.

In reality, the car on the left has the right of way - the person on the right is not meant to overtake them within the last few metres.

In reality they do, obnoxiously bullying their way past, safe in the knowledge that the timid / slower driver who has been gracious enough to act responsibly is unlikely to risk causing a crash.

So - in lots of cases - they repainted the road markings to emphasise that the car on the right DOES NOT HAVE the right to brazen their way past.

I'm not saying that's what happens on roundabouts, but it would mean that there was suddenly a different rule; and the fact that it's different while not actually solving the issue means that it's dangerous.

Not having a go - it was a decent and genuine effort and I acknowledge and appreciate that; but it's unfortunately not a solution and would - IMHO - be dangerous, with rear-ends in the left lane as a direct result.

There is a small difference: marking like that can be consistent with markings at the entrance. You enter the RB, take your lane and follow it. It will guide you to desired exit without a need to cross a single line. With current markings, if the motorist want to obey the signs at entrance, will force him switch lane somewhere at the roundabout.

Turbines work very well in many countries in the continent, in the Netherlands the majority is like that.

ct5amr2ig1nfhp

This is not exactly true. If taking an exit on some roundabouts, you *must* change lane to exit on the left. Finglas roundabout comes to mind. Two lanes split into three lanes, so if you stay in the inside lane you cannot exit on the left. You must change lanes into one of the left two lanes, so you can exit the roundabout.

Turtle-TM wrote: »

You're wrong I'm afraid. You should not change lanes whilst on a roundabout. If you are in the right lane to take an exit and there is a 2 lane exit you stay in lane.

@grogi - in your example, the green car should have given way to the red car so the collision point that Jack Killian pointed out should/could not happen.

Jack Killian

grogi wrote: »

There is a small difference: marking like that can be consistent with markings at the entrance. You enter the RB, take your lane and follow it. It will guide you to desired exit without a need to cross a single line. With current markings, if the motorist want to obey the signs at entrance, will force him switch lane somewhere at the roundabout.

Turbines work very well in many countries in the continent, in the Netherlands the majority is like that.

Markings on the road at the entrance don't work when there's traffic (another bugbear of mine re design) which makes it crucial that, where possible, rules are consistent).

With current markings, if the motorist want to obey the signs at entrance, will force him switch lane somewhere at the roundabout.

Consistently, wherever you are in the country, first time or not, which is relatively safe.

grogi

Jack Killian wrote: »

What happens in a scenario where all the exits are two-lane ? This roundabout is pretty specific with no exit to the east and no entrance to the northwest (I'm guessing some sort of a flyover to the north ?)

In fairness you are trying to solve a problem, but it can't be done in broader, more general terms I'm afraid.

It MAY work for flyover on/off ramps (depending on the number of other exits) but - as I said - you've then got variable rules, which is risky.

Of course not. You want to have more throughput, you need more lanes at the RB. But in majority of cases two or three lanes will be sufficient.

Jack Killian

grogi wrote: »

@grogi - in your example, the green car should have given way to the red car so the collision point that Jack Killian pointed out should/could not happen.

...which is EXACTLY my point; you've merely reversed the "cause" of the collision (at present the red should give way to the green) so it's not a "solution", merely a swap.

grogi

Jack Killian wrote: »

...which is EXACTLY my point; you've merely reversed the "cause" of the collision (at present the red should give way to the green) so it's not a "solution", merely a swap.

One or another driver might misbehave... But by that logic there is nothing you can do, except of building multilevel junction, but even that is not safe, as there will be merge points here and there...

What needs to be done is making sure the markings are good, readable from a car during traffic, consistent within the junction and there is no doubt about how caused a collision.

ct5amr2ig1nfhp

Consistent rules would probably be the most effective solution, seconded by good marking and signage.

It's amazing how many different opinions there are on how to use roundabouts "correctly". Always a fun topic.

grogi

Jack Killian wrote: »

Markings on the road at the entrance don't work when there's traffic (another bugbear of mine re design) which makes it crucial that, where possible, rules are consistent).



Consistently, wherever you are in the country, first time or not, which is relatively safe.

This consistency causes jams unfortunately and limits the bandwidth...

grogi

Isaiah Hot Sneaker wrote: »

Consistent rules would probably be the most effective solution, seconded by good marking and signage.

It's amazing how many different opinions there are on how to use roundabouts "correctly". Always a fun topic.

I always find it funny how behaviour of other drivers changes when I'm driving an old Land Cruiser with a bull-bar...

Jack Killian

grogi wrote: »

This consistency causes jams unfortunately and limits the bandwidth...

Agreed, but safety first.

As I said, roundabouts in this country are a joke, and the reliance on road markings ONLY is a disaster.

Many drivers are also a disaster area, for example like the earlier-mentioned abuse of slow/overtaking lanes.

ct5amr2ig1nfhp

Jack and grogi, would you mind putting up drawings based on grogi's first (left pic) on how each lane 'should' be used?

I did a whip around in the office to see what others think and I'll post up the most popular opinion shortly.

There's a heated debate going on.

Jack Killian

Isaiah Hot Sneaker wrote: »

Jack and grogi, would you mind putting up drawings based on grogi's first (left pic) on how each lane 'should' be used?

I did a whip around in the office to see what others think and I'll post up the most popular opinion shortly.

There's a heated debate going on.

I could but lunchtime's nearly over - leave it with me.

Do you mean "should" as in as per current rules, or "should" as in optimal (which in fairness is what grogi was at least trying, and they put in more thought than the "planners" seem to put into most of them!)

ct5amr2ig1nfhp

Ah it's a bit of craic. Based on the 'current' rules.

I am sure I will get abuse for this but see attached pic anyway.

One person basically said she used whatever lane is free :pac: And she was serious.

About 75% agreement here on this with my view, forgive my paint shop skills. The lines aren't smooth but you get the jist.
Edit: On the single lane exits, shows both cars can merge (safely).

Jack Killian wrote: »

I could but lunchtime's nearly over - leave it with me.

Do you mean "should" as in as per current rules, or "should" as in optimal (which in fairness is what grogi was at least trying, and they put in more thought than the "planners" seem to put into most of them!)

qrx

To me the road markings are to blame. Where the silver car is coming off the M50 onto the roundabout, the left lane should be a left turn only. right lane should be straight on and right only. I'd go so far as to add those flexible plastic bollards\poles after the first exit to stop cars in the left lane going straight on.

I also think the OP made this situation himself. You could clearly see the silver car, there was plenty of time to ease off. OP chose to flex his muscles by driving on top of the silver car and blasting his horn. It's aggessive driving on the part of the OP. Regardless of who was correctly obeying the rules, this should have been a non incident.

Dravokivich

Ok, I'm getting into this a bit late, but too many people seem to be concerned with what occurred and defending it instead of what should of occurred. The car in the outer ring is irrelevant. The OP should have continued to go around the round about as it was not safe for them to exit.

odyssey06 wrote: »

That makes sense. What confuses me is roundabouts where there are two lanes on approach and one on exit.

If there's two lanes on approach, both are going straight through \ taking 12 o'clock exit, but the exit is only single lane, who should yield on exit? The car in the left\outer approach lane or right\inner approach lane?
I'm thinking right\inner should yield?

One should never stop or yield while on the round about. If you are on the inside lane and unable to get to the outside lane for your exit, you need to go around the round about again.

Jack Killian

Isaiah Hot Sneaker wrote: »

Ah it's a bit of craic. Based on the 'current' rules.

I am sure I will get abuse for this but see attached pic anyway.

One person basically said she used whatever lane is free :pac: And she was serious.

About 75% agreement here on this with my view, forgive my paint shop skills. The lines aren't smooth but you get the jist.
Edit: On the single lane exits, shows both cars can merge (safely).

Looks right to me, bar being a little late changing lane northbound. But what about adding in the other 2 entrances ?

The OP's scenario didn't involve a race from the same entrance.

Jack Killian

qrx wrote: »

To me the road markings are to blame. Where the silver car is coming off the M50 onto the roundabout, the left lane should be a left turn only. right lane should be straight on and right only. I'd go so far as to add those flexible plastic bollards\poles after the first exit to stop cars in the left lane going straight on.

That's not the rule of the road though.

I also think the OP made this situation himself. You could clearly see the silver car, there was plenty of time to ease off. OP chose to flex his muscles by driving on top of the silver car and blasting his horn. It's aggessive driving on the part of the OP. Regardless of who was correctly obeying the rules, this should have been a non incident.

Agreed.

grogi

Jack Killian wrote: »

That's not the rule of the road though.

But it is an only one that is simple, easy to understand and easy to implement:

- exit at first exit - take outer lane.
- exit at any other exit - take inner lane...

Jack Killian

grogi wrote: »

But it is an only one that is simple, easy to understand and easy to implement:

- exit at first exit - take outer lane.
- exit at any other exit - take inner lane...

Waste of a lane in most scenarios, especially in the example as westbound only has one lane on exit, meaning few cars use it. Coming from the south that's a complete waste.

Edit: mind you, you've reminded me of something here - roundabouts only really work on "roads of equal importance", with traffic naturally breaking itself up, but Irish powers-that-be chucked them in every junction that they could manage..... must be in order to save on traffic light lightbulbs or something.

Feed Up

Turtle-TM wrote: »

You're wrong I'm afraid. You should not change lanes whilst on a roundabout. If you are in the right lane to take an exit and there is a 2 lane exit you stay in lane.

Can you explain how I'm wrong?

grogi

Jack Killian wrote: »

Waste of a lane in most scenarios, especially in the example as westbound only has one lane on exit, meaning few cars use it. Coming from the south that's a complete waste.

Safety first, remember?!

Jack Killian

grogi wrote: »

Safety first, remember?!

Safety - given some Irish drivers and Irish road layouts - would involve level-crossing barriers!

Throughput, remember ?

qrx

Jack Killian wrote: »

That's not the rule of the road though.

What rules? Show.me rules that govern an unconventional roundabout. Ireland is full of roundabouts with different layouts. The rules are specific to each roundabout, im pretty sure it even says so in the rule book that the standard rules apply unless otherwise stated.

At this roundabout you have an unconventional layout. 2 lanes telling you you can go straight on but only one lane on exit. 2 cars get to the exit, both are in the correct lane...only room for one car.

Jack Killian

qrx wrote: »

What rules? Show.me rules that govern an unconventional roundabout. Ireland is full of roundabouts with different layouts. The rules are specific to each roundabout, im pretty sure it even says so in the rule book that the standard rules apply unless otherwise stated.

At this roundabout you have an unconventional layout. 2 lanes telling you you can go straight on but only one lane on exit. 2 cars get to the exit, both are in the correct lane...only room for one car.

The OP wasn't using that entrance/exit, as they said that they had a two-lane exit.

That two-in from the east nearly even confused me with ProjectMoose's graphic, but they were right.

The "unless otherwise stated" applies to the approach lanes though; there's nothing usually ON a roundabout that varies, as far as I know ?

* ProjectMoose might have encountered something, given that he's seen ones that have stuff I've rarely seen!

Just be glad we don't have the Arc de Triomphe rules anywhere! Although I believe that's the only one they have like that, given that it's an international landmark

ct5amr2ig1nfhp

The two cars merge?

qrx wrote: »

At this roundabout you have an unconventional layout. 2 lanes telling you you can go straight on but only one lane on exit. 2 cars get to the exit, both are in the correct lane...only room for one car.