Today on Architect This City, we have a guest post by Darren Davis, who is a transport planner in Auckland, New Zealand. He’s a regular commenter on this blog, and I know he’s been following the Gardiner East debate quite closely – as many urbanists around the world are. I appreciate him offering and taking the time to write this piece. Thank you.
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The decision this month on whether to demolish the Gardiner East Expressway and replace it with a surface boulevard or to rebuild it with a similar elevated structure will be a watershed moment for Toronto, akin to the decision not to have freeways in the urban core of Vancouver in the late 1970s.
There are numerous good reasons why removing the Gardiner East elevated structure is the right move for Toronto, covered previously by The Globe and Mail and in the Council for Canadian Urbanism’s
Today on Architect This City, we have a guest post by Darren Davis, who is a transport planner in Auckland, New Zealand. He’s a regular commenter on this blog, and I know he’s been following the Gardiner East debate quite closely – as many urbanists around the world are. I appreciate him offering and taking the time to write this piece. Thank you.
——————————–
The decision this month on whether to demolish the Gardiner East Expressway and replace it with a surface boulevard or to rebuild it with a similar elevated structure will be a watershed moment for Toronto, akin to the decision not to have freeways in the urban core of Vancouver in the late 1970s.
There are numerous good reasons why removing the Gardiner East elevated structure is the right move for Toronto, covered previously by The Globe and Mail and in the Council for Canadian Urbanism’s
open letter to Toronto City Council
. If you aren’t aware of these, I strongly recommend reading them.
Also of note are two things:
Just 3% of Downtown commuters drive on the Gardiner Expressway East, a tiny fraction of the 68% who arrive Downtown on public transit.
The “remove” option does not reduce traffic capacity over the “hybrid” option but could reduce travel speeds in uncongested conditions (read on for why I don’t think that this will happen in real life).
However, one element of this debate that has not got much airtime is the transportation modelling that claims an additional two to three minutes travel time with the “remove” option over the “hybrid” option which retains the elevated expressway in a slightly modified form.
Toronto Mayor John Tory has stated that "I didn’t get elected to make traffic worse. And let’s be clear, removing that piece of the Gardiner will almost certainly make traffic worse.” But is it in fact true that demolishing the Gardiner Expressway East will make traffic worse as the transportation modelling claims?
The key thing to understand is that transportation modelling, which tries to predict future travel times, is the product of a bunch of assumptions which may not in fact be borne out in real life.
For example, the effect of induced traffic, where additional traffic capacity leads to additional traffic being attracted to the route, is reasonably well known but generally not factored into transportation modelling. Induced traffic happens because increased travel speeds attracts traffic that would have otherwise avoided the route at congested times; attracts people to drive where they previously used other modes and encourages trips that would not otherwise have taken place. The effect of induced traffic is to quickly nullify the benefits of adding traffic capacity.
However, what is less well known is that the reverse happens where there is either a reduction in traffic capacity (not the case in Toronto as the “remove” option retains the same traffic capacity) or speed.
This is because in this situation, four things happen:
Some travel re-routes. The “remove” option with a widened Lakeshore Boulevard as part of the street grid simply gives more ability for traffic to re-route away from congestion over an elevated expressway structure where drivers are literally trapped until they reach their exit.
Some travel re-times. Some people will retime trips to avoid congested travel times, such as starting and/or finishing work at less congested times.
Some travel changes mode. Some people will be encouraged to change mode by the perceived worsening in traffic conditions.
Some travel is avoided entirely. Some people will choose not to travel at all in the peak of the peak. For example, this could take the form of working from home or shopping on the internet instead of by car.
Transportation models only take into account the first item but not the others. The modelling is also sensitive to traffic growth assumptions and assumed mode split and trip distribution. Often transportation models assume continued growth in car travel even though per capita kilometres travelled peaked about a decade ago.
While this may all sound well and good theory, does this actually happen in practice?
In Auckland city centre, we have extensive experience with the reallocation of road space away from general traffic. Many busy key city centre approach routes have had general vehicle lanes reduced to make way for bus lanes (which generally carry around 65-70% of the people moving capacity of the street).
This has involved up to a 50% reduction in private vehicle capacity (whereas in Toronto, the “remove” option retains the same traffic capacity but may slow throughput). Auckland has done two of these in the past twelve months – both involved converting a general traffic lane to a bus lane.
Don’t get me wrong: There is sometimes pain at implementation with about a three week period of congestion as car drivers adapt to the new reality - and most likely negative media coverage will accompany this. But after about a month, equilibrium will be restored and life will continue much as it did prior to the change.
Part of this is that there will be various “optimisations” during this introductory period where signal timings are adjusted and other tweaks made – the sort of tweaks that can only be fine-tuned in a real world situation. But a bigger part of this is that the four factors above - re–routing, re-timing, mode change and avoided travel - come into play.
I cannot overemphasise enough that life will return to normal surprisingly soon if the Gardiner East Expressway is demolished and replaced by a widened Lakeshore Boulevard.
My advice
When people talk about two to three minutes of extra travel time, take the foregoing into account and take those claims with the very big grains of salt that they deserve. If Toronto makes the right choice and chooses the “remove” option, my bet is that the biggest surprise of all will be how little difference it makes to peak travel times for the 3% of Downtown commuters who used to use the Gardiner Expressway East.
Disclaimer
The author of the above post is an employee of Auckland Transport, however, the views, or opinions expressed in this post are personal to the author and do not necessarily represent the views of Auckland Transport, its management or employees. Auckland Transport is not responsible for, and disclaims any and all liability for the content of the article.
Yesterday I ran a quick 3-4 question survey on ATC called homes for families. The objective was to get a sense of people’s preferences for apartment vs. ground-related housing (house or townhouse) when it comes time to raise a family.
The results are public so anybody can take a look at the data. At the time of writing this post there were already 70 responses. That’s not a huge data set, but the data is more or less what I expected to see.
Here’s what I found (if the data set was larger, I would have made charts):
The vast majority of respondents were from Toronto. No surprise there. That reflects the readership of this blog, which itself can be quite Toronto-centric at times. (I’ve been trying to branch out more, I swear.) That said, I was thrilled to also see respondents from cities like Seattle, Denver, Chicago, Porto, and Sydney.
Of the people who specified that they have kids, 11% live in an apartment. 17% live in a townhouse. And 72% live in a house. If you add houses and townhouses together, you get 89% of people with kids living in some kind of ground-related dwelling.
Of the people who specified that they don’t have kids, 61% live in an apartment. 6% live in a townhouse. And 33% live in a house. This is the kind of split that I generally expected to see for Toronto.
For the people who specified that they don’t have kids, they were then asked where they plan to move if/when they do have kids. 13% plan to move to another apartment. 8% plan to move to a townhouse. 33% plan to move to a house. 23% don’t plan to move (i.e. they are planning to stay put). And 23% don’t plan to have a family.
Interestingly enough, 100% of the people who said that they were not planning to move, were already living in a ground-related housing unit (a house in almost all of the cases). So in reality – and if you exclude the people who don’t plan to have kids – about 83% of respondents expect to raise their kids in a house or townhouse.
Again, this isn’t a big sample size, but the trend appears more or less flat. 89% of respondents who already have kids are already living in a ground-related unit. And when people were asked to project where they would like to be living once they have kids, 83% said they want a house or townhouse.
Do you think these numbers accurately reflect consumer preferences in your city?
. If you aren’t aware of these, I strongly recommend reading them.
Also of note are two things:
Just 3% of Downtown commuters drive on the Gardiner Expressway East, a tiny fraction of the 68% who arrive Downtown on public transit.
The “remove” option does not reduce traffic capacity over the “hybrid” option but could reduce travel speeds in uncongested conditions (read on for why I don’t think that this will happen in real life).
However, one element of this debate that has not got much airtime is the transportation modelling that claims an additional two to three minutes travel time with the “remove” option over the “hybrid” option which retains the elevated expressway in a slightly modified form.
Toronto Mayor John Tory has stated that "I didn’t get elected to make traffic worse. And let’s be clear, removing that piece of the Gardiner will almost certainly make traffic worse.” But is it in fact true that demolishing the Gardiner Expressway East will make traffic worse as the transportation modelling claims?
The key thing to understand is that transportation modelling, which tries to predict future travel times, is the product of a bunch of assumptions which may not in fact be borne out in real life.
For example, the effect of induced traffic, where additional traffic capacity leads to additional traffic being attracted to the route, is reasonably well known but generally not factored into transportation modelling. Induced traffic happens because increased travel speeds attracts traffic that would have otherwise avoided the route at congested times; attracts people to drive where they previously used other modes and encourages trips that would not otherwise have taken place. The effect of induced traffic is to quickly nullify the benefits of adding traffic capacity.
However, what is less well known is that the reverse happens where there is either a reduction in traffic capacity (not the case in Toronto as the “remove” option retains the same traffic capacity) or speed.
This is because in this situation, four things happen:
Some travel re-routes. The “remove” option with a widened Lakeshore Boulevard as part of the street grid simply gives more ability for traffic to re-route away from congestion over an elevated expressway structure where drivers are literally trapped until they reach their exit.
Some travel re-times. Some people will retime trips to avoid congested travel times, such as starting and/or finishing work at less congested times.
Some travel changes mode. Some people will be encouraged to change mode by the perceived worsening in traffic conditions.
Some travel is avoided entirely. Some people will choose not to travel at all in the peak of the peak. For example, this could take the form of working from home or shopping on the internet instead of by car.
Transportation models only take into account the first item but not the others. The modelling is also sensitive to traffic growth assumptions and assumed mode split and trip distribution. Often transportation models assume continued growth in car travel even though per capita kilometres travelled peaked about a decade ago.
While this may all sound well and good theory, does this actually happen in practice?
In Auckland city centre, we have extensive experience with the reallocation of road space away from general traffic. Many busy key city centre approach routes have had general vehicle lanes reduced to make way for bus lanes (which generally carry around 65-70% of the people moving capacity of the street).
This has involved up to a 50% reduction in private vehicle capacity (whereas in Toronto, the “remove” option retains the same traffic capacity but may slow throughput). Auckland has done two of these in the past twelve months – both involved converting a general traffic lane to a bus lane.
Don’t get me wrong: There is sometimes pain at implementation with about a three week period of congestion as car drivers adapt to the new reality - and most likely negative media coverage will accompany this. But after about a month, equilibrium will be restored and life will continue much as it did prior to the change.
Part of this is that there will be various “optimisations” during this introductory period where signal timings are adjusted and other tweaks made – the sort of tweaks that can only be fine-tuned in a real world situation. But a bigger part of this is that the four factors above - re–routing, re-timing, mode change and avoided travel - come into play.
I cannot overemphasise enough that life will return to normal surprisingly soon if the Gardiner East Expressway is demolished and replaced by a widened Lakeshore Boulevard.
My advice
When people talk about two to three minutes of extra travel time, take the foregoing into account and take those claims with the very big grains of salt that they deserve. If Toronto makes the right choice and chooses the “remove” option, my bet is that the biggest surprise of all will be how little difference it makes to peak travel times for the 3% of Downtown commuters who used to use the Gardiner Expressway East.
Disclaimer
The author of the above post is an employee of Auckland Transport, however, the views, or opinions expressed in this post are personal to the author and do not necessarily represent the views of Auckland Transport, its management or employees. Auckland Transport is not responsible for, and disclaims any and all liability for the content of the article.
Yesterday I ran a quick 3-4 question survey on ATC called homes for families. The objective was to get a sense of people’s preferences for apartment vs. ground-related housing (house or townhouse) when it comes time to raise a family.
The results are public so anybody can take a look at the data. At the time of writing this post there were already 70 responses. That’s not a huge data set, but the data is more or less what I expected to see.
Here’s what I found (if the data set was larger, I would have made charts):
The vast majority of respondents were from Toronto. No surprise there. That reflects the readership of this blog, which itself can be quite Toronto-centric at times. (I’ve been trying to branch out more, I swear.) That said, I was thrilled to also see respondents from cities like Seattle, Denver, Chicago, Porto, and Sydney.
Of the people who specified that they have kids, 11% live in an apartment. 17% live in a townhouse. And 72% live in a house. If you add houses and townhouses together, you get 89% of people with kids living in some kind of ground-related dwelling.
Of the people who specified that they don’t have kids, 61% live in an apartment. 6% live in a townhouse. And 33% live in a house. This is the kind of split that I generally expected to see for Toronto.
For the people who specified that they don’t have kids, they were then asked where they plan to move if/when they do have kids. 13% plan to move to another apartment. 8% plan to move to a townhouse. 33% plan to move to a house. 23% don’t plan to move (i.e. they are planning to stay put). And 23% don’t plan to have a family.
Interestingly enough, 100% of the people who said that they were not planning to move, were already living in a ground-related housing unit (a house in almost all of the cases). So in reality – and if you exclude the people who don’t plan to have kids – about 83% of respondents expect to raise their kids in a house or townhouse.
Again, this isn’t a big sample size, but the trend appears more or less flat. 89% of respondents who already have kids are already living in a ground-related unit. And when people were asked to project where they would like to be living once they have kids, 83% said they want a house or townhouse.
Do you think these numbers accurately reflect consumer preferences in your city?
Back in 2011, the The Pembina Institute published a report called, Building transit where we need it. And in it they quite clearly outlined the population densities that are needed to make various types of transit investment cost effective.
For subway they specify a minimum population density of 115 people per hectare and for light rail (LRT) they specify a minimum population density of 70 people per hectare.
And the reason for this is because there’s a strong correlation between population density (i.e. land use) and transit ridership. The two go hand in hand and should not be decoupled. If population densities are too low (as they are, for example, along the Sheppard subway line here in Toronto), people don’t take transit. They drive.
Here’s a chart from the report showing the current and projected population densities for Toronto’s existing and proposed routes (keep in mind this is from 2011).
So what does this chart tell us?
Subways don’t make a lot of sense in many parts of the city. LRT will do just fine.
The Sheppard subway line is an under-utilized asset. Even by 2031 we’ll barely be reaching the requisite population densities.
The Bloor-Danforth corridor could use more intensification.
Unfortunately, transit decisions are often made based on politics instead of data. And that results in subways in places that don’t make a lot of sense. That’s unfortunate because it means less riders, less revenue, and more subsidies.
The other challenge with running subways through low density neighborhoods is that it then creates tension when the city and developers go to intensify those neighborhoods through transit-oriented development. (See #DensityCreep.)
But if we’re going to be fiscally irresponsible about where we deploy our transit capital, the least we could do is upzone the surrounding areas and impose minimum population densities.
In fact, here’s what I think we should do: Land use should be bundled with the transit decision.
Instead of asking where the subway station should go, we should be asking where the subway station should go and all the density needed to bring the area up to a certain minimum population density. And if that second criteria for whatever reason can’t be met, then we don’t build the line.
I wonder if we framed the question in this way if it would change where subway lines get approved. What do you think?
Back in 2011, the The Pembina Institute published a report called, Building transit where we need it. And in it they quite clearly outlined the population densities that are needed to make various types of transit investment cost effective.
For subway they specify a minimum population density of 115 people per hectare and for light rail (LRT) they specify a minimum population density of 70 people per hectare.
And the reason for this is because there’s a strong correlation between population density (i.e. land use) and transit ridership. The two go hand in hand and should not be decoupled. If population densities are too low (as they are, for example, along the Sheppard subway line here in Toronto), people don’t take transit. They drive.
Here’s a chart from the report showing the current and projected population densities for Toronto’s existing and proposed routes (keep in mind this is from 2011).
So what does this chart tell us?
Subways don’t make a lot of sense in many parts of the city. LRT will do just fine.
The Sheppard subway line is an under-utilized asset. Even by 2031 we’ll barely be reaching the requisite population densities.
The Bloor-Danforth corridor could use more intensification.
Unfortunately, transit decisions are often made based on politics instead of data. And that results in subways in places that don’t make a lot of sense. That’s unfortunate because it means less riders, less revenue, and more subsidies.
The other challenge with running subways through low density neighborhoods is that it then creates tension when the city and developers go to intensify those neighborhoods through transit-oriented development. (See #DensityCreep.)
But if we’re going to be fiscally irresponsible about where we deploy our transit capital, the least we could do is upzone the surrounding areas and impose minimum population densities.
In fact, here’s what I think we should do: Land use should be bundled with the transit decision.
Instead of asking where the subway station should go, we should be asking where the subway station should go and all the density needed to bring the area up to a certain minimum population density. And if that second criteria for whatever reason can’t be met, then we don’t build the line.
I wonder if we framed the question in this way if it would change where subway lines get approved. What do you think?
