Road design, safety and Vision Zero

[Bytor]

Here's a design for a Dutch-style turbo-roundabout layout for 4-lane arterial road and 2-lane neighbourhood collector street done with Ontario HTA compliant markings. 

Basically, the curblets prevent people from changing lanes once in the roundabout, but emergency vehicles can still easily mount them if need be.



I probably should Y-split the roads where they touch the circle to allow for a smoother transition into theroundabout instead of the sharp corners, but you get the picture.

[danbrotherston]

Here's a design for a Dutch-style turbo-roundabout layout for 4-lane arterial road and 2-lane neighbourhood collector street done with Ontario HTA compliant markings. 

Basically, the curblets prevent people from changing lanes once in the roundabout, but emergency vehicles can still easily mount them if need be.



I probably should Y-split the roads where they touch the circle to allow for a smoother transition into theroundabout instead of the sharp corners, but you get the picture.

I mean, the whole point is NOT to do that in order to slow traffic lol. For a turbo roundabout maybe a little contouring is expected. FWIW, I think islands on the four lane road would be appropriate, crossing four lanes of traffic is pretty dangerous. And I'm not sure of the scale, the crossings feel pretty far from the circle.

I'm curious, what did you use to create this? It looks excellent!

[ijmorlan]

I mean, the whole point is NOT to do that in order to slow traffic lol. For a turbo roundabout maybe a little contouring is expected. FWIW, I think islands on the four lane road would be appropriate, crossing four lanes of traffic is pretty dangerous. And I'm not sure of the scale, the crossings feel pretty far from the circle.

I'm curious, what did you use to create this? It looks excellent!

As drawn, trucks would be simply unable to navigate it at all. But on the other hand, slowing traffic at the pedestrian crossings is I think supposed to be a goal of roundabouts. So the splitting/curving should be done with both goals in mind, not just to make motor vehicles move smoothly.

What we really need is a design where the radius experienced by trucks is larger than the radius experienced by passenger vehicles (but still not so large that they can blow through without slowing significantly). I don’t have any brilliant ideas on how to make that work.

[danbrotherston]

I mean, the whole point is NOT to do that in order to slow traffic lol. For a turbo roundabout maybe a little contouring is expected. FWIW, I think islands on the four lane road would be appropriate, crossing four lanes of traffic is pretty dangerous. And I'm not sure of the scale, the crossings feel pretty far from the circle.

I'm curious, what did you use to create this? It looks excellent!

As drawn, trucks would be simply unable to navigate it at all. But on the other hand, slowing traffic at the pedestrian crossings is I think supposed to be a goal of roundabouts. So the splitting/curving should be done with both goals in mind, not just to make motor vehicles move smoothly.

What we really need is a design where the radius experienced by trucks is larger than the radius experienced by passenger vehicles (but still not so large that they can blow through without slowing significantly). I don’t have any brilliant ideas on how to make that work.

This is actually pretty simple to do, what it's called is "truck aprons", basically a curb where trucks are allowed to drive up but cars are not. They are already used in some places with traffic signals in the region (and much more broadly outside the region): https://www.google.com/maps/@43.4062017,...384!8i8192

They can be used in roundabouts as well if needed. Our roundabouts already use the mountable centre median to "allow" trucks to navigate which are too large for the roundabout.

I don't like these options all that much though...they don't provide a safe refuge for peds, and drivers tend to ignore them and just drive over them. They might allow our engineers the ability to make better designs, but only because they're insanely conservative already. For example, the intersection I linked can easily manage all but the largest of oversized vehicles without the truck apron, even without using the second lane, and given there is a second lane to swing into extremely oversized vehicles should just use that.

The same situation applies for our roundabouts. Unless they are literally moving a wind turbine blade, even the largest semi-trucks never mount the center median, so why did we spend money paving it?! What a waste!

I would point that out in Bytor's design as well, we don't know what lane widths are in use here, but even the conservative Dutch roundabouts use 5 meter lanes. So if that was the case in Bytor's design, and mountable curbs are used, I would argue even a large semi truck could navigate it, using both lanes as is but if a significant fraction of the traffic was large vehicles like semi-trucks, small affordances could make it navigable by semi-trucks using a single lane, if those trucks use both entrance lanes, which is also reasonable.

And if you need to accommodate the largest of oversized vehicles, you can again use an apron in the centre.

But when it comes to it, this insistence on accommodating the very largest of vehicles in the normal lanes (without using multiple lanes) is again, part of why our roads are so unsafe, our engineers (and other road users) should get used to oversized trucks using more of the road than would normally be permitted.

[Bytor]

I probably should Y-split the roads where they touch the circle to allow for a smoother transition into theroundabout instead of the sharp corners, but you get the picture.[/b]

I mean, the whole point is NOT to do that in order to slow traffic lol. For a turbo roundabout maybe a little contouring is expected. FWIW, I think islands on the four lane road would be appropriate, crossing four lanes of traffic is pretty dangerous. And I'm not sure of the scale, the crossings feel pretty far from the circle.

Even Dutch roundabouts do not have corners that sharp.

I'm curious, what did you use to create this? It looks excellent!

Inkscape.

[bravado]

Decided to bike through the new unfinished roundabout at Beverly and Dundas in Cambridge today. This is the roundabout that is planned to have the LRT cross through it eventually en route to downtown Galt.

I'm no expert, but I am curious about these cutouts in the new curb (photo #3) at the point where the rail corridor used to be in the bushes - and will be again in Ion Phase 2. Or they're nothing and I'm just a curious onlooker!


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[danbrotherston]

Hmm..

It's hard to tell exactly what's going on here because the perspective is hard to read.

The curb cut that starts directly where the paved portion of the sidewalk ends (closest to the camera) that is right where the jog in the curb is...is for bike lanes transitioning to the MUTs that surround the circle.

See an example here: https://www.google.com/maps/@43.4294683,...384!8i8192

FWIW...I should give our engineers a little credit, they appear to have improved their design for the bike transition to the roundabout. It is now less oblique to the bike lane and (while it's hard to tell in the photo for sure) the curb looks flatter. The old design was dangerous because attempting to move up a lip...even a small one sideways on a bike is a recipe for a crash.

It looks like there is another curb cut immediately after that section, although its hard to see in the photo for sure. It seems too far from the circle to be the pedestrian crossing...and looking at the first photos, it looks like the crossing is not aligned, but again, it's hard to see in the perspective. But at the same time, I don't see another curb cut closer to the circle, so it seems like it would have to be the ped crossing.

You might know better having been there.

[bravado]

Hmm..

It's hard to tell exactly what's going on here because the perspective is hard to read.

The curb cut that starts directly where the paved portion of the sidewalk ends (closest to the camera) that is right where the jog in the curb is...is for bike lanes transitioning to the MUTs that surround the circle.

See an example here: https://www.google.com/maps/@43.4294683,...384!8i8192

FWIW...I should give our engineers a little credit, they appear to have improved their design for the bike transition to the roundabout. It is now less oblique to the bike lane and (while it's hard to tell in the photo for sure) the curb looks flatter. The old design was dangerous because attempting to move up a lip...even a small one sideways on a bike is a recipe for a crash.

It looks like there is another curb cut immediately after that section, although its hard to see in the photo for sure. It seems too far from the circle to be the pedestrian crossing...and looking at the first photos, it looks like the crossing is not aligned, but again, it's hard to see in the perspective. But at the same time, I don't see another curb cut closer to the circle, so it seems like it would have to be the ped crossing.

You might know better having been there.

I like this answer - since the newly finished section of Dundas has on-street painted bike lanes that will need to transition into the roundabout sidewalk spaces. The older section of road is still waiting on the very expensive railway bridge removal and replacement to see how the rest of the bike lanes will work.

[danbrotherston]

Also, just because I'm "that guy" and because I cycle through this intersection pretty much daily, here's an example from the Netherlands of the "right" way to transition to a cyclepath around a roundabout:

https://www.google.com/maps/@52.1591964,...384!8i8192

Notice, NO curbs for cyclists, just a smooth connection.

To be honest, I don't really understand why our engineers have problems with things like this. It seems to be a struggle for them to understand how to do drainage properly, but it's not like the Netherlands is a dry place with no drainage issues. FWIW...I almost never seen water pooling the way we do in Ontario.

[Acitta]

Also, just because I'm "that guy" and because I cycle through this intersection pretty much daily, here's an example from the Netherlands of the "right" way to transition to a cyclepath around a roundabout:

https://www.google.com/maps/@52.1591964,...384!8i8192

Notice, NO curbs for cyclists, just a smooth connection.

To be honest, I don't really understand why our engineers have problems with things like this. It seems to be a struggle for them to understand how to do drainage properly, but it's not like the Netherlands is a dry place with no drainage issues. FWIW...I almost never seen water pooling the way we do in Ontario.

Also, our roundabouts lack a giant bull sculpture.

[danbrotherston]

Also, just because I'm "that guy" and because I cycle through this intersection pretty much daily, here's an example from the Netherlands of the "right" way to transition to a cyclepath around a roundabout:

https://www.google.com/maps/@52.1591964,...384!8i8192

Notice, NO curbs for cyclists, just a smooth connection.

To be honest, I don't really understand why our engineers have problems with things like this. It seems to be a struggle for them to understand how to do drainage properly, but it's not like the Netherlands is a dry place with no drainage issues. FWIW...I almost never seen water pooling the way we do in Ontario.

Also, our roundabouts lack a giant bull sculpture.

Yeah, that one is quite fun.  I feel like it might actually not help limit distraction at roundabouts lol.

[cherrypark]

Also, just because I'm "that guy" and because I cycle through this intersection pretty much daily, here's an example from the Netherlands of the "right" way to transition to a cyclepath around a roundabout:

https://www.google.com/maps/@52.1591964,...384!8i8192

Notice, NO curbs for cyclists, just a smooth connection.

To be honest, I don't really understand why our engineers have problems with things like this. It seems to be a struggle for them to understand how to do drainage properly, but it's not like the Netherlands is a dry place with no drainage issues. FWIW...I almost never seen water pooling the way we do in Ontario.

NL cyclist wrist health supported by good infra design.

[danbrotherston]

Also, just because I'm "that guy" and because I cycle through this intersection pretty much daily, here's an example from the Netherlands of the "right" way to transition to a cyclepath around a roundabout:

https://www.google.com/maps/@52.1591964,...384!8i8192

Notice, NO curbs for cyclists, just a smooth connection.

To be honest, I don't really understand why our engineers have problems with things like this. It seems to be a struggle for them to understand how to do drainage properly, but it's not like the Netherlands is a dry place with no drainage issues. FWIW...I almost never seen water pooling the way we do in Ontario.

NL cyclist wrist health supported by good infra design.

That good design is also their upright bikes...although you can just add tushy and spine health to the list.

[danbrotherston]

Well...

https://www.reddit.com/r/IdiotsInCars/co...t_in_bike/

I mean it's hard to know the complete context, but certainly an example of the cyclist or pedestrian 'coming out of nowhere'.

Of course what's frustrating is this is how drivers describe 99% of collisions where they hit a VRU.

[tomh009]

Wow. Fortunately I have not seen anyone doing this in our area ...