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.
. 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.
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?
T E S L A by Thomas Juel on 500px
Yesterday I posted a video about the career of Elon Musk. And it reminded me of something that’s been on my mind as I think about transportation, cities, and the future.
Elon’s story for why he founded SolarCity, Tesla, and SpaceX is incredibly compelling. He chose problems and industries that he felt would move humanity forward. He felt that we needed sustainable forms of energy production (SolarCity), sustainable forms of transport (Tesla), and a way for humans to occupy other planets (SpaceX). That’s incredible ambition.
Today though, I just want to focus on the transportation piece.
Electric and driverless vehicles, I believe, are a step in the right direction. I honestly believe that at some point in the not too distant future we’re going to look back at that time when people used to drive their own cars and wonder how we ever allowed that to happen.
But fundamentally, I think there still remains a question of how best to plan our cities.
There’s lots of talk today about peak car and the death of the automobile. Certainly within planning and urbanist circles, there’s an almost universal belief that planning (most of) our cities around the car, as opposed to people, was a huge mistake. Multimodal solutions with a public transit backbone are now the way forward.
But will that always be the case as the notion of the “car” evolves?
Intuitively, driverless vehicles feels like a massive opportunity to leverage data and better optimize our private transport assets. We know that the utilization rate for most private cars is incredibly low and so there’s lots of room to improve how we use and share private vehicles and how we move people around cities.
But how big is that opportunity? Does a city filled with driverless electric vehicles and with networks like Uber mean that public transportation now becomes less important? And if so, how much less important?
I can’t help but feel like private and public transport are on a collision course right now. I suppose that isn’t anything new. But this time around I wonder if private transport won’t figure out a way to achieve similar efficiencies to large scale public transport.
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?
T E S L A by Thomas Juel on 500px
Yesterday I posted a video about the career of Elon Musk. And it reminded me of something that’s been on my mind as I think about transportation, cities, and the future.
Elon’s story for why he founded SolarCity, Tesla, and SpaceX is incredibly compelling. He chose problems and industries that he felt would move humanity forward. He felt that we needed sustainable forms of energy production (SolarCity), sustainable forms of transport (Tesla), and a way for humans to occupy other planets (SpaceX). That’s incredible ambition.
Today though, I just want to focus on the transportation piece.
Electric and driverless vehicles, I believe, are a step in the right direction. I honestly believe that at some point in the not too distant future we’re going to look back at that time when people used to drive their own cars and wonder how we ever allowed that to happen.
But fundamentally, I think there still remains a question of how best to plan our cities.
There’s lots of talk today about peak car and the death of the automobile. Certainly within planning and urbanist circles, there’s an almost universal belief that planning (most of) our cities around the car, as opposed to people, was a huge mistake. Multimodal solutions with a public transit backbone are now the way forward.
But will that always be the case as the notion of the “car” evolves?
Intuitively, driverless vehicles feels like a massive opportunity to leverage data and better optimize our private transport assets. We know that the utilization rate for most private cars is incredibly low and so there’s lots of room to improve how we use and share private vehicles and how we move people around cities.
But how big is that opportunity? Does a city filled with driverless electric vehicles and with networks like Uber mean that public transportation now becomes less important? And if so, how much less important?
I can’t help but feel like private and public transport are on a collision course right now. I suppose that isn’t anything new. But this time around I wonder if private transport won’t figure out a way to achieve similar efficiencies to large scale public transport.
