Roads: Roundabouts

[W. K. Lis]

 

[lenaitch]

Almost nobody stops at stop signs​

See link.

The curious thing about that intersection is there is absolutely zero potential for conflict between vehicles; it's a one-way intersecting a one-way. The only potential conflict is between vehicles and pedestrians and it seems they are respecting each other.

 

[reaperexpress]

We discussed that roundabout with stop signs in 2012 (link).

The Toronto Star also wrote an article about it shortly following our discussion.

There’s not much point in a traffic circle that always requires drivers to stop.

Traffic circles, also called roundabouts, are rare in Ontario but extensively used in other places — particularly in Europe — as an alternative to stop signs, allowing vehicles to keep moving.

As long as drivers yield to traffic already in the intersection, they can proceed without coming to a stop, which seems safer than creating the conditions for pushy people to coast through the intersection.

Larry Koch emailed us about a curious contradiction at two small traffic circles on Broadway Ave., one at Banff Ave. and the other three blocks to the east, at Rowley Ave.

The circle at Rowley is set up like traffic circles just about everywhere else — a sign cautions drivers to yield to vehicles in the intersection, but otherwise, sail on sailor.

But there are stop signs for drivers at all four corners at Broadway and Banff, even though the roundabout and traffic conditions appear identical to those at Rowley.

We went to Rowley and watched as drivers approached the circle and continued on their way without a hitch when no traffic was in the intersection. When there was, they yielded without issue.

But Banff is an all-way stop, which confused some drivers who appeared to overlook the stop sign and thought they were allowed to proceed.

We saw one driver slow down but continue through, while a driver to his right who had arrived just before and came to a stop had to slam on his brakes to make way for the guy who didn’t.

It resulted in horn honking and hand gestures from the guy who obeyed the stop sign, and quite likely an indignant shrug from the driver who coasted through without stopping.

Rowley and Banff are dead-end streets that end just north of Broadway, which means hardly any traffic comes from that direction, which lessens the need for stop signs at either.

STATUS: We’ve asked transportation services if there’s a good reason why there are stop signs at Banff but not at Rowley, or if it is just an overly cautious mistake.

 

[Undead]

There's a similarly stupid set up at Gary and Wendell in the Pelmo Park area.

 

[W. K. Lis]

There's a similarly stupid set up at Gary and Wendell in the Pelmo Park area.

From link.

 

[reaperexpress]

The center lane (ie the through route to continue north on Hespeller) ceasing to be the center route is the puzzle. And, while one isn’t supposed to change lanes, the centre lane splits and necessitates a choice in order to stay in the centre lane (not a frequently used choice, I imagine, but counterintuitive to the “vanilla” two lane roundabout train of thought).

It’s very clever flow-wise, but KISS it isn’t, and if we are trying to train people to follow a basic set of roundabout rules, this doesn’t fit that approach. Roundabouts should not be complicated, even if it traffic flows may suggest logical adaptations.

That’s where I was going with my Hespeler Road example. The layout is not consistent with these rules, nor is it consistent with the rule of “never change lanes in a roundabout”.

I think you may be misinterpreting the meaning of "not changing lanes in the roundabout". When you enter a multi-lane roundabout in Ontario you may need to cross other lanes to reach the lane which leads to your destination (see for example, the left lane in blue below). But then once you have turned into your correct lane you need to follow it to its conclusion. Many of our roundabouts do include some very basic turbo-roundabout features, including your example here, so the lane will generally spiral outward on its own.

Here is every legal movement within this roundabout. Note that none of them ever cross a lane marking once they are within the circle. You simply enter in the correct lane, and it will spiral you out to your desired exit. In some cases there are two possible exits, because the lane splits at some point.

I personally find it misleading that they use dashed lane markers within roundabouts, even in the places where it is never legal to cross them. I would use solid lines, except in the locations where entering traffic crosses the lane.

How do the slip lanes align to the “if in the right lane, always turn right at the first exit“ premise ?

It doesn't because that's not a premise. The correct premise is "follow the lane designation signs".

The general rule that I have learned (the hard way) is that one should never enter a 2-lane roundabout in parallel to another vehicle, because there are too many places where the vehicle in the center has the right to cut across the outside lane to reach an exit, without even checking their blind spot.

The car in the centre lane never has the right to cut across any lane. They exit wherever their lane leads them to. As you can see in the diagrams above, every lane spirals out on its own. It is perfectly fine to enter a roundabout simultaneously with another vehicle as long as you yield to traffic in all lanes within the circle before doing so. If either of the blue cars below crash into a red car, then the blue car has failed to yield to traffic in the circle.

The painted arrows on approach to this roundabout do give some clues, but at the last minute....and this roundabout isn't even symmetrical, so those instructions are direction-and lane-specific. There may be regulatory signs, but the congitive task for drivers to analyse those plus the painted arrows plus lane markings, at speed or in bad weather, is error-friendly.

Painted arrows are not "clues", they are a reinforcement to the regulatory signs. The process of picking a lane prior to an intersection is exactly the same whether it's a roundabout or a traffic signal. If your lane turns into a right turn lane, but you don't want to turn right, you need to leave that lane!

I'm not even sure that the engineering and design standards are sufficiently consistent to be able to train drivers, because no two roundabouts are identical and there are permutations and combinations that are hard to predict. Adding the requirement to signal to that is a brain teaser.

There is no more need to train drivers on every possible permutation of a roundabout than it is to train them on every possible lane configuration at a traffic signal. You just need to teach people the basic principles, which includes new simple rules like "dont change lanes within the roundabout", "signal right when you plan to exit the circle", and existing common sense rules like "don't go straight from the right turn lane".

See my green arrow, for instance - is the exit a right signal or no signal? How do I go from Hespeler Rd northbound to Beaverdale without changing lanes in the roundabout ?

I agree that this design makes the theoretical requirement to signal counterntuitive, because the exit radius is basically infinite, making it look like a straight through movement. In addition, that design is extremely dangerous for pedestrians because it encourages traffic to accelerate before having reached the crosswalk across the exit lanes.

Here is a quick sketch where I tightened up the exit radii to clarify what is a "turn" (exiting the roundabout) versus "straight" (staying in the circle):

 

[crs1026]

^ Thanks for the excellent explanation. I am definitely learning a few things.

My one comment is that the “pick your lane” signage and road paint has to be far enough back from the intersection to allow a safe, undisruptive lane change. If every roundabout has a different design, that is not something the driver can anticipate. With traditional intersections it’s pretty obvious that you need to be in the right lane to turn right, and v.v for turning left. In a roundabout, with too little notice, one may be tempted to make a panic correction to get to the proper signed lane. (My Garmin is pretty helpful with this actually - but its database is a bit out of date)

That leads to the other design principle that I have misunderstood - which is, my belief that if you miss your turn it’s ok to keep circling and try again. The turbo feature means, if you miss your lane to exit, you need to take the only legal route out of the roundabout and find a place to turn around.

It may sound like I am more clueless than I should be, but that’s the point, I guess….. I’m a typical older driver who did all their driver’s ed learning before there were any roundabouts in Ontario.

- Paul

 

[reaperexpress]

My one comment is that the “pick your lane” signage and road paint has to be far enough back from the intersection to allow a safe, undisruptive lane change. If every roundabout has a different design, that is not something the driver can anticipate. With traditional intersections it’s pretty obvious that you need to be in the right lane to turn right, and v.v for turning left. In a roundabout, with too little notice, one may be tempted to make a panic correction to get to the proper signed lane. (My Garmin is pretty helpful with this actually - but its database is a bit out of date)

Yes, as with all intersection types you need to provide enough notice for drivers to sort into the correct lane. At a roundabout the order and distribution of lanes will be pretty much the same as with a traffic signal. The left turns will always be on the left lane and the right turns will always be from the right lane. It's the stuff in the middle which varies.

That leads to the other design principle that I have misunderstood - which is, my belief that if you miss your turn it’s ok to keep circling and try again. The turbo feature means, if you miss your lane to exit, you need to take the only legal route out of the roundabout and find a place to turn around.

Correct. One side-effect of the turbo design is that it is not possible to recirculate indefinitely like at a single-lane roundabout or an old-fashioned multilane roundabout. Here is the longest turn I could find at this roundabout:

It may sound like I am more clueless than I should be, but that’s the point, I guess….. I’m a typical older driver who did all their driver’s ed learning before there were any roundabouts in Ontario.

No worries, it's really the fault of our driver education system for not keeping licensed drivers up to date with current road designs and regulations.

This is why I believe we need mandatory driver retesting every 10 years or so. It's not just about reminding people about the rules/behaviours they have forgotten, it's about informing them about the changes which have happened in the previous decade. For example, the HTA was amended in 2016 with changes such as introducing "shark's teeth" yield markings, changing the laws about yielding in crosswalks, designating bicycle signals, etc. But in the absence of driver retraining, it won't be until around 2096 that all licensed drivers are aware of those changes. And yet drivers can be charged with violating any of those new/changed laws today, and lack of knowledge is not a valid legal defense.

 

[Woodbridge_Heights]

The worst roundabout in Toronto that I know of? Broadway and Banff Avenues. Yes, there's a 4-way stop there. (From Google Maps)

That's not a roundabout, that's a traffic calming measure...

 

[crs1026]

There are parts of the world (Ireland being one example) where traditional intersections have been converted to roundabouts, without adjusting curbs or geometry.... simply by painting a white circle in the middle of the intersection. The big benefit is there is no longer any traffic control to maintain, and much less vehicular stopping. (or bicycle stopping, for that matter) It would be an interesting practice to look at in Ontario.

- Paul

 

[turini2]

There are parts of the world (Ireland being one example) where traditional intersections have been converted to roundabouts, without adjusting curbs or geometry.... simply by painting a white circle in the middle of the intersection. The big benefit is there is no longer any traffic control to maintain, and much less vehicular stopping. (or bicycle stopping, for that matter) It would be an interesting practice to look at in Ontario.

- Paul

Noting that these "mini roundabouts" do prioritise cars over pedestrians and cyclists - but yes, they are more efficient and safer than a 4 way stop.

 

[afransen]

There are parts of the world (Ireland being one example) where traditional intersections have been converted to roundabouts, without adjusting curbs or geometry.... simply by painting a white circle in the middle of the intersection. The big benefit is there is no longer any traffic control to maintain, and much less vehicular stopping. (or bicycle stopping, for that matter) It would be an interesting practice to look at in Ontario.

- Paul

How well would that work with snow covered streets? I think you'd need some signage as well, and ideally some geometric cues.

 

[nfitz]

That's not a roundabout, that's a traffic calming measure...

Precisely - and they've been around for many decades - long before modern roundabouts where invented in the 1950s or 60s.

Lol only toronto would put stop signs at a roundabout.

very common for these little circles (not roundabouts). I don't see many in Toronto, but they are all over the place in cities like Vancouver and Seattle.

 

[lenaitch]

How well would that work with snow covered streets? I think you'd need some signage as well, and ideally some geometric cues.

The one thing many people forget or don't know is that road markings have no force in law in Ontario, exactly for this reason.

 

[crs1026]

The one thing many people forget or don't know is that road markings have no force in law in Ontario, exactly for this reason.

I did know that, actually….. but, some times they are the sole indicator of an HTA restriction that is not signed…. Passing on hills and curves being an example.
I have wondered whether those black and white regulatory signs are ergonomically effective. They serve a legal purpose well - but lane markings and geometry are far better at giving drivers clues that prevent errors…. Wearher permitting, that is.

- Paul