Star: City Hall eyes traffic circles

[allabootmatt]

Uhh...Eglinton Road?

Guess the Post fired its fact-checkers.

 

[adma]

Anyone who's ever studied how things work outside this continent would never dismiss roundabouts as "goofy". The general public can be forgiven for their ignorance of how they work, but members of the works committee should be educated in things like this. Calling roundabouts goofy makes about as much sense as calling stop signs goofy.

Mr. Wheeler?

 

[CDL.TO]

Going straight from no roundabouts to roundabouts only at high-volume intersections sounds like trouble to me. A two or three lane roundabout is an entirely different creature from a one-lane installation. Expecting people to change lanes while turning while looking for their exit while still driving defensively without giving them time to adjust to this new concept will likely be problematic.

Britain has been moving away from roundabouts at high-volume locations because they don't work. Basically, the moment you have to put traffic lights on a roundabout, the advantages are lost.

 

[MisterF]

Expecting people to change lanes while turning while looking for their exit while still driving defensively without giving them time to adjust to this new concept will likely be problematic.

You don't change lanes in a roundabout.

http://www.region.waterloo.on.ca/web/region.nsf/roundabouts_how_to_use2.html

You're right though, they should probably be used on moderate capacity roads like Vaughan Rd before they're installed on busier streets. Do you have a link for Britain removing high capacity roundabouts? I've read they can handle 60,000 vehicles per day.

 

[CDL.TO]

You don't change lanes in a roundabout.

Depends on the design. If it's low-capacity and there's only one lane in the roundabout you don't. High-capacity roundabouts have multiple lanes. Look at this one in London, it's three lanes all the way around AND has "bypasses" on each corner allowing left-turners (our right-turners) to avoid the roundabout entirely. This is not abnormal, it's common. Notice the "keep clears" painted on the roadway. When bad congestion occurs on a roundabout a nasty case of gridlock happens where traffic entering the roundabout blocks traffic from exiting it causing, err..., "circle-lock".

(For craziness scroll just a bit to the north and look at the Cherry Lane roundabout).

On the flipside, roundabouts have been proliferating in the UK at low and and medium traffic intersections like a bad case of the measles. Sometimes all they do is paint a while circle in the middle of the road. I've even seen them at the end of driveways

Do you have a link for Britain removing high capacity roundabouts? I've read they can handle 60,000 vehicles per day.

I'm not sure if they've actually been removing any. I'll look for an article on it when I get home from work tonight.

 

[MisterF]

Depends on the design. If it's low-capacity and there's only one lane in the roundabout you don't. High-capacity roundabouts have multiple lanes. Look at this one in London, it's three lanes all the way around AND has "bypasses" on each corner allowing left-turners (our right-turners) to avoid the roundabout entirely. This is not abnormal, it's common. Notice the "keep clears" painted on the roadway. When bad congestion occurs on a roundabout a nasty case of gridlock happens where traffic entering the roundabout blocks traffic from exiting it causing, err..., "circle-lock".

(For craziness scroll just a bit to the north and look at the Cherry Lane roundabout).

On the flipside, roundabouts have been proliferating in the UK at low and and medium traffic intersections like a bad case of the measles. Sometimes all they do is paint a while circle in the middle of the road. I've even seen them at the end of driveways



I'm not sure if they've actually been removing any. I'll look for an article on it when I get home from work tonight.

I know multi lane roundabouts are common, that's exactly what's shown in the link in my last post. You're still not changing lanes in the roundabout. You go into the appropriate lane before you even get into the roundabout, stay in that lane in the circle, and exit directly from that lane. If traffic entering the roundabout is blocking traffic in it, that sounds like a design flaw. Circulating traffic should never get blocked, that's the whole point to the give way rule that led to modern roundabouts in the first place. Does circulating traffic have to yield to traffic entering or something? Looks like there's a stop bar right in the middle of the roundabout.

And that Cherry Lane one to the north isn't a roundabout....it's a mess!

 

[CDL.TO]

I know multi lane roundabouts are common, that's exactly what's shown in the link in my last post. You're still not changing lanes in the roundabout. You go into the appropriate lane before you even get into the roundabout, stay in that lane in the circle, and exit directly from that lane. If traffic entering the roundabout is blocking traffic in it, that sounds like a design flaw. Circulating traffic should never get blocked, that's the whole point to the give way rule that led to modern roundabouts in the first place. Does circulating traffic have to yield to traffic entering or something? Looks like there's a stop bar right in the middle of the roundabout.

Defining the "inside lane" as the one being near the centre of the roundabout, and "outside lane" being the one near the edge, but still with driving on the right...

That link that you posted showed no lane markings on the roundabout. That's ambiguous and makes it look like it only has one lane. What of someone turning left using the inside lane coming from the west while someone from the east is going straight ahead? They could both be following the rules and still collide as someone tries to exit the roundabout from the inside lane while the person in the outside lane tries to go straight.

With what I'm familiar with in England, you never exit a roundabout from the inside or middle lane. If you're on a three lane road coming to a three-lane roundabout, and want to turn left, you would enter the inside lane, then move over one lane towards the outside after each exit so you find yourself on the outside by the time you reach your exit. If you look at the Google Map image I provided, two of the roundabout exits are 1 lane, one is 2 lanes, and one is 3 lanes.

There's a stop bar at one place on the roundabout because there's traffic lights there as I described in a previous post. Traffic entering the roundabout gets a green light, backups happen for whatever reason, traffic can't get off the roundabout, gridlock occurs.

 

[MisterF]

Defining the "inside lane" as the one being near the centre of the roundabout, and "outside lane" being the one near the edge, but still with driving on the right...

That link that you posted showed no lane markings on the roundabout. That's ambiguous and makes it look like it only has one lane. What of someone turning left using the inside lane coming from the west while someone from the east is going straight ahead? They could both be following the rules and still collide as someone tries to exit the roundabout from the inside lane while the person in the outside lane tries to go straight.

With what I'm familiar with in England, you never exit a roundabout from the inside or middle lane. If you're on a three lane road coming to a three-lane roundabout, and want to turn left, you would enter the inside lane, then move over one lane towards the outside after each exit so you find yourself on the outside by the time you reach your exit. If you look at the Google Map image I provided, two of the roundabout exits are 1 lane, one is 2 lanes, and one is 3 lanes.

There's a stop bar at one place on the roundabout because there's traffic lights there as I described in a previous post. Traffic entering the roundabout gets a green light, backups happen for whatever reason, traffic can't get off the roundabout, gridlock occurs.

People both enter and exit from the inside lane in English roundabouts. You're never supposed to be right beside someone in a roundabout, even one with two lanes. Well I guess you could be beside someone when you're turning right, no harm done there. Here's some video of roundabouts in action - really busy ones too. Here's another one - two lanes with no lane markings like that diagram.

That one in London doesn't look like a properly designed roundabout. How old is it? Having signals controlling the traffic inside the roundabout defeats the purpose of having a roundabout in the first place.

 

[CDL.TO]

I'm not sure when it was built, but as I've said lights on large roundabouts are very common because they have a capacity limit. You can't "widen" a roundabout like you can a road once things get busy.

Those videos showed setups that I'm used to, nothing new there. The second one certainly didn't show volumes the we would be seeing at Don Mills and Eglinton. The first one shows as the guy drove through the intersection he moved outwards towards his exit. And there was plenty of driving right beside each other (That's just silly, what's the point of a multi-lane roadway if you're not allowed to drive beside someone?). A roundabout can be three lanes while an exit might only be one or two... obviously three lanes of traffic can't all exit out on to one lane.

Let me show you another high-traffic roundabout in London (one that I'm very familiar with). The M25/A10 junction. This one isn't obscured by the highway running over it and you can see line markings on the street and how it all works. Just like a tiny 400-series highway, a roundabout has "onramps" and "offramps", some with more lanes than others. Some lanes on the "highway" exit the "highway", some stay on, and some split allowing people to do either. Destinations for each lane is marked on the street. If you start on the road coming in from the north, you'll see that the inside lane is marked "M25 WATF'D". After entering the roundabout, the inside lane is still marked "M25 WATF'D". After the first exit, "M25 WATF'D" has moved over one lane towards the outside. After the next exit, "M25 WATF'D" is now on the outside lane.

This all provides a nice illustration of how traffic flows through a roundabout are supposed to work. It's much easier when you're dealing with low or moderate traffic flows, but that isn't what we have at Eglinton and Don Mills.

I love roundabouts. We should have has them here for years now. I'm just saying that it's foolish to think that we could introduce them at high-volume locations first, such as where a 6-lane road intersects a 6-lane road, and not expect problems. Sure, they're good for dealing with congestion; but that doesn't mean that the first place you introduce something completely new is at the most congested locations! They need to be phased in at intermediate-volume locations first.

 

[MisterF]

I'm not sure when it was built, but as I've said lights on large roundabouts are very common because they have a capacity limit. You can't "widen" a roundabout like you can a road once things get busy.

Those videos showed setups that I'm used to, nothing new there. The second one certainly didn't show volumes the we would be seeing at Don Mills and Eglinton. The first one shows as the guy drove through the intersection he moved outwards towards his exit. And there was plenty of driving right beside each other (That's just silly, what's the point of a multi-lane roadway if you're not allowed to drive beside someone?). A roundabout can be three lanes while an exit might only be one or two... obviously three lanes of traffic can't all exit out on to one lane.

Let me show you another high-traffic roundabout in London (one that I'm very familiar with). The M25/A10 junction. This one isn't obscured by the highway running over it and you can see line markings on the street and how it all works. Just like a tiny 400-series highway, a roundabout has "onramps" and "offramps", some with more lanes than others. Some lanes on the "highway" exit the "highway", some stay on, and some split allowing people to do either. Destinations for each lane is marked on the street. If you start on the road coming in from the north, you'll see that the inside lane is marked "M25 WATF'D". After entering the roundabout, the inside lane is still marked "M25 WATF'D". After the first exit, "M25 WATF'D" has moved over one lane towards the outside. After the next exit, "M25 WATF'D" is now on the outside lane.

This all provides a nice illustration of how traffic flows through a roundabout are supposed to work. It's much easier when you're dealing with low or moderate traffic flows, but that isn't what we have at Eglinton and Don Mills.

I love roundabouts. We should have has them here for years now. I'm just saying that it's foolish to think that we could introduce them at high-volume locations first, such as where a 6-lane road intersects a 6-lane road, and not expect problems. Sure, they're good for dealing with congestion; but that doesn't mean that the first place you introduce something completely new is at the most congested locations! They need to be phased in at intermediate-volume locations first.

Look closer at those videos I posted - both show vehicles entering and exiting to and from the inside lane. You can really see it at the end of the first video.

Sure, they're good for dealing with congestion; but that doesn't mean that the first place you introduce something completely new is at the most congested locations! They need to be phased in at intermediate-volume locations first.

I agree.

edit: are lights on roundabouts more common on motorway interchanges than other roads? I don't remember any lights in roundabouts when I was in England, except maybe at those big ones at motorway interchanges.

 

[CDL.TO]

I think lights are more common at motorway junctions because those are high-volume locations. Junctions seem to be further apart from one another in the UK, so the ones that do exist tend to be very busy. They factor this is to new designs of interchanges.

As for exiting from the inside lane, it's tough for me to comment completely because I can't see the complete layout of that particular roundabout. It all comes down to the lane markings and what people are told to do. People are exiting from the inside lane (two lane roundabout, two lane exit), but people are not continuing on the roundabout while in the outside lane which is something the Waterloo illustration presented as being permissible and would inevitably result in accidents. I guess the point is there's more at work in terms of the rules than simply stating that you can't drive next to someone else.

 

[Redroom Studios]

I had my first experience with roundabouts in England this past summer. Let me first state that between being new to travelling through them with such frequency and getting used to traffic driving on the opposite side of the road I was literally blown away by all of it. My brain could not keep up with the speed and non-stop flow of it, with cars seemingly going in every direction! This was especially the case when you were confronted with what I will call a complex of roundabouts - where several of them link into each other in a cluster. I must agree with one of the previous posts above that British/European drivers are much more skilled than N.A. drivers. They all drive standard transmissions, operate in very tight quarters and navigate the roundabouts with great efficiency. I arrived in Manchester and there was about a 90 minute drive to where I was staying... I think I recall hitting perhaps one or 2 stoplights on that entire drive - fantastic!

I dont know if we will ever be able to replicate the system they have there. I have heard quite a few horror stories about the roundabouts in Waterloo region... so many people have no clue how to negotiate them. Hopefully it will improve with time and I am all for progress and efficency.

 

[Prometheus The Supremo]

I have heard quite a few horror stories about the roundabouts in Waterloo region... so many people have no clue how to negotiate them. Hopefully it will improve with time and I am all for progress and efficency.

i bet they even pronounce them roundaboots!

 

[lawsond]

Yes, almost everyone who's used roundabouts enough to get used to them and compare them with regular intersections likes the roundabout choice.

has anyone ever talked to a haligonian on this issue?
there were two rotarys (as they call them) in that city.
the mic mac rotary HAD to be dismantled as it was a terrible traffic snarl each and every morning and afternoon.
nothing but backups as far as the eye could see.
it was so bad (how bad was it) that it was choking off development in dartmouth.
so mic mac had to go.
the armdale rotary has been the source of many a traffic report ever since i can remember.
they also installed traffic lights there which rather takes away the point of it all.
in short...BEWARE.

 

[lawsond]

^^^
further to that, the mic mac rotary was designed much like a modern roundabout and not like a traffic circle with a very wide diamater and many lanes.
but it was a mess. they cannot handle volume.
they just can't.