Friday, 5 February 2016

Greenfield Development Cross Sections

I was wanting to write about this for a while. The city produced a series of suggestions for what new areas of the city might have in terms of what roads might look like. I decided to go over them to see if they make sense, and how they could be improved.

The link to the actual document is here:

They contradict a number of things contained in Sustainable Safety. Roads must only have one purpose to the greatest possible degree. Given that we have almost literally a blank slate, except for some farms, pipelines and other utility lines and what we have already developed, maybe a railway or two, we can design pretty much as we would if we were to go to a random point in the province and start building a city. So having a street oriented collector road and especially street oriented arterial road means that it will absolutely go against Monofunctionality. A road is a through road, for high speed traffic at a high flow rate, focuses near absolutely on flow, an access road, focused absolutely on giving access to homes and properties at a low speed and low flow rate, or a distributor for medium speeds, medium flow but exchange at intersections.

Secondly, while the local access roads in new areas of the city do normally appear to be for residents only and quite uninviting to drive along if you don't need to be there, and with a speed limit of 30 km/h (and design speed of 30), it will do that just fine, but collector roads mix the wrong kinds of traffic together. It has on street parking, which slows down traffic, and they are big heavy objects with 0 speed not well separated from the main part of the roadway. But it doesn't provide a bicycling path. Given that bike lanes should be our last choice, and because we can start with a blank slate, we can almost certainly eliminate the need for bike lanes. And note that just being on a bike route or not isn't sufficient for determining whether or not it should have a dedicated bicycling space, it has to accommodate for the fact that mixing 50 km/h traffic, often several thousand vehicles per day, and the city likes to put bus routes on these collectors, and if you're from London or Utrecht, you know very well what happens if you mix bus and bicycle, is dangerous.

And the fact that we lack design suggestions for building dedicated bus only roads, busways for short, in ordinary neighbourhoods also means that we have less of an opportunity to separate the bus flows from the rest of traffic, meaning that we mix big and small vehicles, and we lack an opportunity to give buses priority and direct routes where collector roads are normally curvy and not that direct.

Arterial roads also have their flaws. Why are so many 4 lane divided arterial roads built? Many of them function like distributor roads, but they are still 4 lane roads. If they were distributors, they should be 50 km/h zones. If they were through roads, they should be 70 km/h roads. But they are 60 zones, and their design makes them a mystery. And while they are direct lines leading from one part of a district to another, and from district to district, they also have destinations directly off of them. Most shopping areas in newer developments, I would even suggest that all of them probably are, directly accessed by the arterial. This creates car dependency, and by making the most convenient way to access them is by a car on an artery, this is what you end up getting. Especially given that alternate accesses are often of poor quality, if even present, narrow sidewalks coming off of obscure local access roads. If an arterial is supposed to be a through road, it should have a speed limit of 70 km/h and have between 2 and 3 lanes per direction, a divide between the 2 directions, and rarely interacting with side roads. If they were distributor roads, then they should be single lane roads with a speed limit of 50 km/h, and it may or may not have a divide between the two directions.

It also seems like it offers quite a few options for the kind of development that would be adjacent. Commercial for example is different than residential. But in new developments, why would you need a commerce street or these car oriented commercial centres like this one:,-113.5162574,722m/data=!3m1!1e3?hl=en when you could have a pedestrianized shopping centre for each district, like this one: instead?

A few other nitpicks include the sidewalk width, Dutch modern practice advises a 2 metre wide standard sidewalk, 1.8 metres minimum, and sometimes 2.5 metres or more. What we might call a shared use path in the Netherlands is really just a bike path that happens to not have a sidewalk due to the near total lack of pedestrians. And those should be 3 metres wide at a bare minimum. 3.5-4 metres should the be the standard width. The buffer between sidewalk and road is pretty good, in fact if you added curb extensions, the 2.5 metre boulevard space and the width of the car parking lane would be 5 metres or one car length of space. But because we don't want car parking, that would need to change.

The width of the car lanes is astoundingly wide. 4 metres on a number of diagrams? Despite a legal maximum of 2.6 metres for even the largest vehicles? Why? 3 metres is already plenty. The Dutch don't even use 4 metres for their motorway (and through road) lanes designed for 130 km/h! The curbside lane on arterial roads is 4.45 metres! How much speeding are we expecting here? It actually takes conscious effort to go 60 on the 60 km/h arterials, if I don't the speeds will over time drift towards 70. Even 3.2 is a bit much for a collector road.

Another odd aspect of the cycle track/arterial design is why is the cycle track so close to the moving traffic? Why is such a large boulevard between cyclists and pedestrians when it would be much more useful between the cycle track and roadway.

Let's come up with some new standard cross sections.

Through road, 70 km/h. 4 lanes. No busway. Non bus stop:

Through road, 70 km/h. 4 lanes. No busway. Bus stop: (the bus bay is in an indented bay with a median separating the bus bay from the roadway to limit the possibility of collisions with the main flow of traffic).

Through road, 70 km/h, 4 lanes, busway, non bus stop:

Through road, 70 km/h, 4 lanes, busway, bus stop:

Distributor road, 50 km/h, 2 lanes, No busway, non bus stop:,

Distributor road, 50 km.h, 2 lanes, No busway, bus stop:

Distributor road, 50 kmh, 2 lanes, busway, non bus stop:,

A local access road (one way road):

And finally, a pedestrianized shopping centre:

These new cross sections provide an alternative to what the city proposes, and designs that fairly provide for all road users on easy to use and easy to understand, efficient and especially, safe routes. Why won't the city and province and other places around the world accept that cycling, walking and transit is becoming more popular and that the AASTO guidelines are out of date and need a major revision?

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