Traffic calming and effective street cross-sections

[ijmorlan]

Adding a bunch of stop signs is hugely inefficient.  So much fuel is wasted in the deceleration/stop/acceleration cycle.  A better solution is to provide a design that allows a car to continue at a constant, lower speed.  Fuel consumption is minimized this way.

Excellent point. That is also a reason why I don’t like speed bumps much — they encourage slowing to almost nothing right at the speed bump, but then the natural tendency is to accelerate rapidly away from them.

I came up with a good rule for one-way streets however: any one-way street with no lane markings should only be one-way for motor vehicles. In other words, counterflow bicycle traffic should be allowed. Of course, if there are lane markings, an explicit counterflow bicycle lane can be provided, but we shouldn’t need to individually debate each specific one-way minor street.

[tomh009]

Adding a bunch of stop signs is hugely inefficient.  So much fuel is wasted in the deceleration/stop/acceleration cycle.  A better solution is to provide a design that allows a car to continue at a constant, lower speed.  Fuel consumption is minimized this way.

Which is why humps (as used in Doon, for example) are better than the traditional bumps.  You can maintain a comfortable 40 km/h over those in most cars (maybe not a Smart, though, given the super-short wheelbase), and avoid the acceleration/deceleration cycle.

[Canard]

LOL, I actually love speed humps in my smart. Problem is, I actually speed up to go over them, to catch some air!

[timc]

Not sure if this has been mentioned, but when I lived in England I saw that many residential streets (two-lane) had a one-lane chokepoint (no idea of the proper name) every so often. This was also a crossing point for pedestrians. Only one car could go through at a time. I'm certain this was a traffic calming measure designed to slow down the boy racers.

There are some places in Waterloo that are like this. Blythwood Road is similar. I'm not sure if it is quite one lane, or more like a lane-and-a-half, but it is where the school crossing is.

[clasher]

It's too bad more people don't drive with fuel economy in mind.

Glasgow street has some really annoying traffic calming on the hill coming off Fischer-Hallman with the bike lane turning into a paved boulevard that people use for their garbage cans. It's just suc a grab bag of islands and stuff but it doesn't really seem to make much difference whenever I pass through people are going well over 40

[Canard]

Becoming a hypermiler is what made me a safer and calmer driver. Always keeping that number in view (L/100 km, both instantaneous and average) I think should be a legal requirement for all cars going forward!

When you start thinking that way, your driving just becomes smoother and calmer automatically.

[ijmorlan]

It's too bad more people don't drive with fuel economy in mind.

Glasgow street has some really annoying traffic calming on the hill coming off Fischer-Hallman with the bike lane turning into a paved boulevard that people use for their garbage cans. It's just suc a grab bag of islands and stuff but it doesn't really seem to make much difference whenever I pass through people are going well over 40

Of course, part of the problem there is that the limit on Glasgow should be 60, because it is a major regional thoroughfare, not a local residential street. The fact that it is lined with houses is just a planning screw-up. It’s one of the original roads and should have been designated as primarily a traveling route, not local access, when the city expanded to include it.

And most people here know how much I support car culture.

[danbrotherston]

Glasgow is actually an interesting road for a number of reasons. First, it has several very different sections, the east of Belmont (which is uninteresting, it's a too wide 50 km/h road).

Between Belmont and Westmount, it is a very narrow two lane road with bike lanes. Here, no traffic calming, and yet, most drivers respect the 40km/h limit. The 40 km/h limit is at least in part due to the school, but the design of the road and the housing makes it appropriate (really all our residential streets should be designed and have a 40 limit). It's narrow, which makes the bike lanes uncomfortable, but traffic is usually pretty slow, which helps.

The section between Westmount and Fischer-Hallman is a whole different story. The limit here shouldn't be 40 (by our rules). There is no school, there aren't that many houses. The reason it is 40 km/h (in my opinion at least) is the same reason there is no sidewalk on the north side even though the road is rebuilt and there was supposed to be one. The people on that street have an unusually large amount of political influence. You can speculate as to why.

Given the 40 km/h limit the road is enormously wide. So obviously speeding was a huge issue. Residents complained (and of course are listened too), and traffic calming was installed. It is effective, speeds were reduced substantially, and around the traffic calming are now within the 40 limit.

However, the traffic calming is utterly life threatening for cyclists. Realistically, if drivers want to stay between the island and the bike lane, speeds should be around 20-30 km/h. That of course never happens, drivers simply swerve into the bike lane to maintain 40-45 km/h. Sometimes, even regardless of if there is a cyclist.

Not to mention the curbs installed for the "segregated bike lane" portion are not terribly smooth and pose a danger to cyclists going down the hill.

And of course, there is nearly continual bike lane parking on that road. When I used to bike it, rare was the morning that I didn't stop to call in a parked vehicle.

Of course, everyone complains about the traffic calming...even the residents, who wanted it.

[isUsername]

I just saw this GIF that happens to show the importance of a good streetscape design.

Cover the outside thirds of the GIF and then cover only the inside third of the GIF. You should notice that the image appears to slow down doing the first and speed up doing the second.



This reminds me of Queen St. S., where the speed limit is 50 km/h, but people tend to drive at or slightly slower than 50 km/h, thanks to the street lamps, trees, and other items close to the roadside that makes them think they're driving faster than they may normally think.

[jamincan]

Wow, that's a really great illustration of the effect. It intuitively makes sense that people will slow down in a tighter space, but I didn't realize that the sense of speed actually changed too.

[chutten]

I like curb extensions for traffic calming and pedestrian crossings. Drivers are less likely to kill pedestrians when they can see them, and divers are more likely to see them if they're visually separated from the "normal" curbside.

...what laws would be broken if, say, someone were to tear up curbs down one or both sides of a rather wide street and adjust the width to a more sensible value? Assuming the curbs were reinstated "to code". Similarly, what is the penalty for emplacing traffic control signs alongside a thoroughfare?

Asking for a friend.

[danbrotherston]

I like curb extensions for traffic calming and pedestrian crossings. Drivers are less likely to kill pedestrians when they can see them, and divers are more likely to see them if they're visually separated from the "normal" curbside.

...what laws would be broken if, say, someone were to tear up curbs down one or both sides of a rather wide street and adjust the width to a more sensible value? Assuming the curbs were reinstated "to code". Similarly, what is the penalty for emplacing traffic control signs alongside a thoroughfare?

Asking for a friend.

Curb extensions work, but must be integrated with bike infrastructure, otherwise you end up with insane things like this:  https://www.google.ca/maps/@43.4550765,-...!1e3?hl=en

Yes, that is in fact, a brand new curb in the middle of a brand new bike lane.......

As for what would happen, I would imagine you would be admonished, possibly fined, probably not jailed, and the city would probably not do anything unless some staff members felt it was dangerous.  So...it's really up to the prerogative of those involved.

[Viewfromthe42]

It's a very interesting trigonometry phenomenon. Our eyes only really engage with a certain angular width before we go from the active area, to a semi-awareness area, to peripheral vision, to nothingness. When you're driving, everything is "coming at you" at your driving speed, but your perception of it is very different depending on your proximity to those objects. If an object is 100m away from you and it gets 10m closer to you in 1s, it doesn't really seem like it's moving that fast since it's only shrunk the distance to you by 10% (going from 100m away to 90m away). Meanwhile, if an object is 11m from you and gets 10m closer to you in 1s, it feels like it's moving really fast since it's shrunk the distance between you by 91% (going from 11m away to 1m away; I don't want it to hit you ). For reference, 10m/s is 36km/h

If you draw a V-shape on a piece of paper and then two lines on either side of it, say 1cm from the bottom tip of the V and from each other (like so: | | V | |), you can see this effect. Extend the V until it intersects all four lines, each half of the V intersecting two lines. Note how the first line is intersected much closer to the tip of the V and the second line is intersected much farther from the tip of the V. Now imagine you are the tip of the V, the V itself is your active vision area (which is indeed an angular cone extending out from whatever you're focusing on), and the close lines represent a street line Queen, whereas the far lines represent a street like University Ave (especially near RIM Park).

The wider the street, the sooner objects "fall out of" your V, out of your area of active focus. In the wide street, it might fall out of your active view area when it's only reducing the distance between it and you by 10% in that instant. In the narrower street, because the object is so much closer to you before it falls out of your visual focus, it's potentially reducing the distance between it and you by much more than 10% in that instant, and so it feels much faster. (Technical note: this perception effect is primarily due to angular velocity. When a car is coming at you in the other lane and it is far away, it might only take up a few degrees of your vision span, and the degrees it occupies [let's say 0 being straight ahead] might change from 1 through 3 to degrees 5 through 10 very slowly [and they do expand]. When it gets close, it will wind up going from being centered on degree 30 to being centered on degree 45 very quickly, and shoots fastest through degree 90. Yes, I'm getting a bit confused myself, hence calling it a technical note)

So what would be interesting to do would be to find out how fast most drivers felt comfortable driving, how wide their view arc was, and make it such that objects felt like they were going at that fastest-comfortable speed right as they were falling out of the active visual area for drivers driving at the posted speed limit, by putting those street-side objects at the appropriate distance from the driving lane.

Another note would be that the lower a driver sits in their seat, the slower they will think they are going. The same angular V effect happens, because the dashboard rises into their field of view, and makes the roadway disappear farther in front of the car, making it seem like they are going slower than they are. So for short folks who do not adjust their seats to an appropriate height (certainly if I can't see your mouth over the steering wheel, you're far too low in your car), or for folks who intentionally like to sit low-slung in their seats, they are setting themselves up to drive faster and to feel more comfortable doing so.

[ijmorlan]

I just saw this GIF that happens to show the importance of a good streetscape design.

Cover the outside thirds of the GIF and then cover only the inside third of the GIF. You should notice that the image appears to slow down doing the first and speed up doing the second.



This reminds me of Queen St. S., where the speed limit is 50 km/h, but people tend to drive at or slightly slower than 50 km/h, thanks to the street lamps, trees, and other items close to the roadside that makes them think they're driving faster than they may normally think.

Absolutely amazing. My initial thought was something along the lines of, “that might be kind of cool, but it’s not going to be that amazing”. Then I tried it, and had to check that somebody hadn’t installed some sort of hand proximity sensor on my computer monitor. It really felt like covering the middle third sped up the action.

[ijmorlan]

Curb extensions work, but must be integrated with bike infrastructure, otherwise you end up with insane things like this:  https://www.google.ca/maps/@43.4550765,-...!1e3?hl=en

Yes, that is in fact, a brand new curb in the middle of a brand new bike lane.......

As for what would happen, I would imagine you would be admonished, possibly fined, probably not jailed, and the city would probably not do anything unless some staff members felt it was dangerous.  So...it's really up to the prerogative of those involved.

This is exactly the kind of thing that just confirms me in my belief that I know more than most planners.

Normally I respect expertise — I never think that I know more than the astronomer, or the people down the hall from me who know way more about system administration, or the concrete guy I hired to replace the path to the side door of my house — but clearly there is a severe problem when supposed professionals produce something like this. It’s almost like they’re trying to drag planning down to the level of computer programming.