All things environmental

Musings about the environment and all it touches, from education to city planning

One-way arterials: why not Broadway? or Commercial?

with 2 comments


One-way arterials can handle more traffic, that’s well known (because cars don’t need to wait to turn left, lights can be synchronized, etc; see here and here). But large one-way streets don’t have a good reputation, as opposed to narrow residential streets, because the faster traffic they promote is hostile to pedestrians (faster speeds mean more noise and water splash, and accidents are worse). Vancouver turned Hornby street from one-way to both ways for this very reason.

A nice parklet on wide one-way St-Denis in Montreal

A nice parklet on wide one-way St-Denis in Montreal

But it seems that no-one ever looks at the corollary: if a one street has more capacity, then a narrower one-way street can have the same capacity as a two-way street. The same ability to move traffic at reasonable speed, while accommodating other uses: a reserved transit corridor, for instance, or wider sidewalks, or segregated bike paths.

Let’s take the Broadway-12th avenue pair, for instance. For most of its length, Broadway is six lanes wide, while 12th is four lanes wide. (This remains true when 12th turns into 10th at MacDonald; only when 12th becomes Grandview does the width increases.)

Imagine this: Broadway is now one-way west, while 12th is one way east. But six lanes going west is a bit of overkill; during the peak of morning rush hour, Broadway has three lanes west, while 12th has two. Add to that the extra throughput of one-way arterials; in effect, it should be possible to reduce Broadway to four lanes west without affecting the carrying capacity of the pair. The eastward returning traffic has ample width on 12th.

That leaves two extra lanes! This could be used for a number of things; one of my favourite is a reserved bus corridor. Since the street is one way, the lights could be programmed to minimize bus waits, and the increased bus capacity would negate the need for a costly subway. Yes, more buses would be needed, but at a fraction of the cost; or a reserved streetcar or LRT corridor could be created.

De Maisonneuve cycling path, Montreal (hey, it looks like Dunsmuir in Vancouver!)

De Maisonneuve cycling path, Montreal (hey, it looks like Dunsmuir in Vancouver!)

That’s one lane – what about the other? Take your pick: sidewalks wide enough to accommodate cafes; segregated bike paths; taxi stands; maybe all of the above. Currently, I find it frustrating to try to shop on Broadway while using the 10th avenue bike path; I always overshoot my destination, and never get to see what new stores have opened – and new stores depend on browsing traffic. Why not a Broadway bike path? German cities has extra-wide sidewalks on commercial streets precisely because bike commuters are also shoppers.

Montreal has such a combination: Ste-Catherine, the shopping artery, is one-way east, while the next street over, De Maisonneuve, is one-way west. But De Maisonneuve also now has a nice segregated bike path, with little negative effect on the carrying capacity of the street pair.

Or imagine, if you will, the Commercial Drive – Victoria Drive pair, between 18th and Powell. The streets meet near 18th, and the intersection is perfect to separate the traffic into a one-way northbound Victoria and one-way southbound Commercial. Commercial is wider, but is a shopping street; again, this would set the stage for wider sidewalks and bike paths. Yes, the Number 20 bus would need to be re-routed north via Victoria; but the streets are near, and there are shops on Victoria that would benefit. Streets for Everyone has done great work (check them out!) on remaking Commercial into a walkable, cyclable street, but which retains the two-way proposal; this is an alternative idea.

There are many pairs of streets like this throughout the city; these are just two of the possibilities. The switch is actually relatively cheap to make; signalisation is affected, little else. Compare that to the very expensive widening of street corners required to create left turn bays, no longer needed.

So we need to rethink one-way arterials. Instead of creating environments hostile to pedestrians and cyclists, wisely designed, they can actually improve walkability and enable bike lanes without sacrificing the carrying capacity of motorized traffic – which, as we know, seems sacrosanct in Vancouver.

Another view for Commercial (but with lowered car traffic capacity)

Another design for Commercial (with two-way traffic, which lowers carrying capacity)


2 Responses

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  1. Traffic expands and contracts to fill the space available. As long as you are not adding lanes of general purpose traffic, then the situation will resolve itself to something like the status quo. In fact lots of space on Broadway is given over to parking – except at peak periods and even then enforcement is spotty at best. But much of the parking – seen as essential by the businesses – could be accommodated elsewhere.

    But 12th is much more a residential street than Broadway. I am as uncomfortable with the idea of making the traffic through there faster as much as I am the idea of surface rapid transit on 16th.

    I also wonder if you intend that transit be diverted to 12th as well – which greatly reduces its convenience as a service to businesses along Broadway.

    At the present time it is hard enough to persuade people that we do not need to add arterial capacity to the road network. We have actually done a pretty good job of absorbing more people in Vancouver without adding much more than the odd turn lane here and there.

    I think the really interesting work is to be done on how to make Broadway a better multi-purpose urban street rather than a better performing arterial road. Wider sidewalks and more opportunities to promote loitering come first: then more transit priority. Amazing that the 99 B-Line moves so many people with so little in the way of on street priority measures.

    Stephen Rees

    November 17, 2014 at 6:05 pm

    • Thanks for the well thought out comment Stephen – much enjoyed. I can’t claim to have put a lot of thought in this idea of one way arterials – and, yes, I hear you, transit eastbound on 12th is questionable – ditto for northbound on Victoria. The post was really prompted by a wish to get a discussion going – I find it quite frustrating that people cannot imagine anything other than the status quo. I also think (but it’s only a hunch, I don’t have the numbers) that if one-ways have indeed higher flow capacity, then part of the street can be reserved for other activities (bus or bike lane, light rail, take your pick) without someone objecting that this will create unbearable inconvenience for the motorists. It’s a win-winn situation – maybe. I may be too optimistic on that count. But bottom line, Broadway frustrates me: It has space to accommodate multi-modal uses, but it doesn’t. And having a reserved lane for buses (and bikes, gawd) at rush hour only, on the right-hand side, barely improves transit flow. I would love to see a true reserved corridor. (Hey, I’d be happy with Broadway cut down to four lanes for motorists, two for transit both east-west…and if motorists squack too much, then one-way for traffic may be an option.) For that matter, wider sidewalks, with – gasp – outdoor seating, European style!

      But thanks for your input. I can’t agre more: we do’t need added arterial capacity for traffic, it’s a self-defeating option. And yes, the 99 does an amazing job, considering; I’d love to see what it could convey with true reserved corridors.


      November 17, 2014 at 8:32 pm

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