Roundabouts !

[EVNow]

It is high time roundabouts got their own thread.

Here are all the issues I see / used to see - along with what seems to be currently fixed.

- Doesn't wait for the vehicle coming from the left. <-- This seems to be fixed in 10.69.25.2.
- Stops for vehicles coming from the right. Those vehicles will wait at the entrance and ego car should proceed without waiting.
- At an empty roundabout, stops and waits for a couple seconds before entering. FSD should slow down (to 10/15 mph) and enter the roundabout without waiting.
- Highly indecisive when navigating a small (or tiny !) roundabout. FSD stops some 50 meters ahead and needs several seconds to figure out how to navigate ... and does so in a very unnatural way i.e. tries to take the "shortest distance" route rather than around the roundabout.
- At multilane entrance of roundabout, creeps too far into the roundabout if there is another vehicle on the left lane blocking the view to the left.

 

[RowdyMY]

Turn signals. Even on the same roundabout they aren't uniformily applied day-to-day so regional traffic code is clearly not the issue.

Heck I confused what it intends to do sometimes and I can see the intentacle.

 

[LowlyOilBurner]

I’ve never used a turn signal in a rotary. This maybe is my error, perhaps I was taught wrong. The use of signals by FSDb in roundabouts puzzles me.

 

[AlanSubie4Life]

I’ve never used a turn signal in a rotary. This maybe is my error, perhaps I was taught wrong. The use of signals by FSDb in roundabouts puzzles me.

In countries where they are common, like the UK, (all this for the UK which is backwards) you must signal right when going around or right, until you pass the exit before your exit whereupon you signal left, and you signal left on approach when immediately exiting left. When going straight, no signal on approach, until you pass the exit before yours, then signal left, and signal when changing lanes in roundabout of course.

It’s just constant signaling and hurtling into and around roundabouts in the UK; it is a very distinctive part of driving there.

Laws in the US will vary by state of course. I just do the above (but the reverse of course) because it helps people out, though not sure anyone pays any attention.

 

[MrBadger]

Roundabouts are simple, although can be made over complex by cascading roundabouts within roundabouts. I’ll ignore the latter as imho each roundabout should be treated in their own right.

From a UK perspective:

There are basically two types plus signalised roundabouts which can be ignored as signalised roundabouts are effectively just a series of signalised junctions.

From a traffic modelling perspective, the two types of roundabouts behave quite differently, and it is this behaviour difference that effectively differentiates the two rather than any design or physical choice although in most circumstances it is normally pretty obvious from the layout how the roundabout is going to behave.

‘Small roundabouts’ would behave similarly to an ‘unprotected’ (not a term we really use here) n-way junction. I’ll gloss over this one as it’s too difficult to explain even when sat next to a learner how they work in practice even if in principal they should be quite simple.

So I will describe ’large roundabouts’ as this seems to be what is being described earlier.

These should be thought of as a spiral road with exits. The spiral will have one or more lanes and an exit may be a dedicated lane or be a flared lane (ie 1 lane splits into n). Simply put, if you move in or out (laterally, ie between lanes) of the spiral you should indicate. Simple. If you have a lane flare, you should signal to indicate your onward path, which may be an exit or continuing around the roundabout. Simple.

For clarity. Unless an exit is a dedicated exit lane, it is a flare so should be signalled, like wise if continuing around the roundabout past the flare, you should signal that intent as it helps road users who may be joining at that point. The reality though is that many do not either because they can’t be bothered or, perfectly valid, because no one is about to join or adjacent on the roundabout so showing your intention will not benefit anyone else.

When asked by my son if he should indicate at a roundabout, I simply said to do so if it would benefit anyone else knowing your intentions. This differed a little from what it sounds like he was taught which seemed to be indicate if you are continuing around the roundabout and indicate if you are exiting - so basically indicating one way or the the other whilst on the roundabout which whilst covers you for all situations, is a lot of the time unnecessary.

The final comment is that whilst the spiral is obvious, your lateral ‘lane’ position within the spiral may not be. In the UK is is very common for a roundabout to potentially have a number of lateral positions on the spiral but for these not to be lane marked. But you should still indicate as you move between these albeit invisible lanes in and out of the spiral.

tl;dr in UK, a roundabout can be treated as a normal road, albeit circular/spiral except when on outer circumference when you should indicate intent as appropriate on whether you want to exit or remain on the roundabout.

Important to note that in UK, priority is to those on the roundabout, but this is not necessarily the case elsewhere. Eg I believe that in France, something like the roundabout around Arc de Triomphe, priority is given to those entering the roundabout.

The spiral concept comes from many traffic modellers that I have worked with (and been briefly trained by) and may not be how it is thought of by many.

 

[randompixel]

Using the road - Roundabouts (184 to 190) is pretty clear on when to signal. What most people can find confusing is when there is more than 3 other exits but no specific lane markings on approach or on the roundabout, for example this one can get lots of random lane discipline and indication.

 

[MrBadger]

What most people can find confusing is when there is more than 3 other exits but no specific lane markings on approach or on the roundabout, for example this one can get lots of random lane discipline and indication.

I know it well - we affectionately call it 5 ways as you have 5 ways to go (not including where you just come from). The problem with that roundabout (Chobham, McLaren, Addlestone/Byfleet, Woking) is that many people stick to the outside radius even if they are not turning off so make entering the roundabout not so easy to know their intentions unless they are clearly indicating, and even then their road position/speed may hint otherwise - so if entering never quite sure if someone is turning off at your road or continuing on round where you want to enter.

 

[aronth5]

The large rotary I take daily is treated by FSD as multi lane even though it doesn't have painted lines. Since nobody ever drives the rotary as if there are 2 lanes except FSD I'm sure makes cars behind me wonder why FDS doesn't just drive in the middle of the 2 lanes.
FSD always stops before entering even though people typically enter at 15-25mph. If anyone is behind me I typically use the accelerator pedal.

Google Maps

 

[EVNow]

Turn signals. Even on the same roundabout they aren't uniformily applied day-to-day so regional traffic code is clearly not the issue.

Heck I confused what it intends to do sometimes and I can see the intentacle.

Well, FSDb applies turn signals whenever it feels it is changing direction more than a certain angle. Thats why it signals even when going on a single lane if the road is twisty.

 

[sleepydoc]

It is high time roundabouts got their own thread.

Here are all the issues I see / used to see - along with what seems to be currently fixed.

- Doesn't wait for the vehicle coming from the left. <-- This seems to be fixed in 10.69.25.2.
- Stops for vehicles coming from the right. Those vehicles will wait at the entrance and ego car should proceed without waiting.
- At an empty roundabout, stops and waits for a couple seconds before entering. FSD should slow down (to 10/15 mph) and enter the roundabout without waiting.
- Highly indecisive when navigating a small (or tiny !) roundabout. FSD stops some 50 meters ahead and needs several seconds to figure out how to navigate ... and does so in a very unnatural way i.e. tries to take the "shortest distance" route rather than around the roundabout.
- At multilane entrance of roundabout, creeps too far into the roundabout if there is another vehicle on the left lane blocking the view to the left.

I think a lot of the issues with roundabouts can be traced back to some other longstanding fundamental issues with FSDb.

• Yields - every roundabout entrance is essentially a right turn on yield. FSDb (11.3.6) still doesn't handle these well so it's no surprise that it doesn't handle roundabouts well.
• Blinkers - blinkers have been a hot mess for the last several versions. Ultimately it seems to be primarily related to lane selection.
• Lane selection - one of the biggest issues with FSD for the past year. FSD still has issues going straight on a regular road. Just like the yields, if it can't handle a regular road well it's no surprise that it has trouble with roundabouts.

On the plus side it seems to be doing better for me lately. Maybe it's just random variation but the last 3-4 roundabouts I've traversed have gone quite well.

 

[PianoAl]

I find that the navigation voice is often wrong when it says, "Enter the roundabout and take the Nth exit." The correct exit may be N+1 or N-1. FSDb takes the correct exit.

Anyone else see that?

 

[sleepydoc]

I find that the navigation voice is often wrong when it says, "Enter the roundabout and take the Nth exit." The correct exit may be N+1 or N-1. FSDb takes the correct exit.

Anyone else see that?

I don’t use voice navigation so I can’t say if the voice is correct but the directions shown on the screen are, FWIW. If the voice is wrong because it can’t determine who h exit it would also be another reason for FSDb to have problems with roundabouts

 

[GoCanes]

I’ve spent the week driving around northern Arizona on FSD and the only issue I’ve had is with all the new rotaries built by AZDOT lately - they’re everywhere & FSD can’t seem to handle them. I’m on 11.4.4 - is anyone having to take over at almost every rotary?

 

[JulienW]

I’ve spent the week driving around northern Arizona on FSD and the only issue I’ve had is with all the new rotaries built by AZDOT lately - they’re everywhere & FSD can’t seem to handle them. I’m on 11.4.4 - is anyone having to take over at almost every rotary?

What is worse than a traffic circle. Thinking (or calculating) a small traffic island is traffic circle and then thinking it is in England and driving around it the wrong way.

 

[jabloomf1230]

FSDb can barely traverse a single lane roundabout when there's no traffic. High traffic situations cause major problems. A multilane roundabout with complete inner and outer loops is a complete disaster. FSDb will do everything wrong except drive clockwise around the roundabout.

 

[JulienW]

I find in general it likes to stop when no one is coming but loves to accelerate when there is traffic in the circle.

 

[APotatoGod]

...

Heck I confused what it intends to do sometimes and I can see the intentacle.

I just need to remark how much I love that phrasing, the intentacle! Brilliant!

 

[clydeiii]

On my typical commute I have a few roundabouts (depending on traffic), 11.4.4 feeling very good, while even as recently as 11.3.6 felt not great.

 

[Phlier]

I don’t even bother with FSDb on traffic circles anymore. It gets clicked off before the car starts to slow for the entrance. Then I re-engage it after the… next update.