rive-sud Autoroute 30 - Discussion générale

[Cataclaw]

I don't have a problem with what you are saying, my issue is that I would very much like to see the facts. I am very curious to see the outcome of the A-25 bridge and the new A-30 in a few years time.

Where did you get this information? I'd like to see before and after figures please.

 

Sure thing peekay. In all sincerity, I understand your skepticism. I was highly skeptic about induced demand at first too... it seems incredibly counter-intuitive at first. It's only when I took a course in transportation modelling, started looking at examples around the world and crunching some numbers myself that I realized how powerful this often misunderstood phenomenon is.

 

According to Concession A25, the A-25 bridge has exceeded its average projections and is now topping 40,000 vpd on some days, and it's rising. New transponders are flying off the shelves like hot cakes.

 

"Le dernier, explique-t-il à La Presse, a été enregistré la veille, 17 mai: 40 894 automobilistes ont passé le pont.

Source: http://www.lapresse.ca/actualites/regional/montreal/201205/23/01-4527793-pont-de-la25-un-anniversaire-un-record-un-recours.php

 

I don't understand your point. Where did all these people come from?

 

Before I get into this, let me define "trip". In transportation science, a "trip" is not grabbing your car keys and going to Quebec City for the weekend. A trip is more basic than that, and is simply defined as transportation from an origin to a destination.

If I leave my home and go to work, that's a trip. If I walk to the depanneur, that's a trip.

 

Changes to a network can affect traffic volume in a number of ways.

When a new link is created, several things happen:

 

1. People that would have previously foregone trips are now choosing to make those trips.

Example: It's saturday night, there is no nightlife in my area, I feel like grabbing a beer somewhere with some friends, but there's too much traffic congestion and I don't feel like negotiating all that, so I'll just stay home or go watch the game at a friend's place nearby. However, now that a fast and efficient road allows me to go to where the the bars and clubs are, I'll choose to go out instead of stay home. I'm generating a new trip that would have otherwise not been made, and I'm doing this solely on the premise that a deterrent (congestion) is now removed from my utility function.

 

Obviously, some people will still go out anyway, even if there is congestion, and some people will choose to stay home, no matter how efficient the roads are. But a certain percentage of users, who were "on the fence", will now start to make those trips.

 

2. Destinations will be change. Example: Suppose there's a local cinema I go to because it's close to me. There's a much nicer cinema with better selection but it's 30 minutes away. Adding a lane to the highway that takes me there allows the travel time to be reduced to 15 minutes. I'll now be tempted to go to that cinema instead of the local one. So I'll drive farther to go to the fancy cinema, but in doing so I'll contribute to the increase in volume along that highway.

 

3. Development will be spurred. New housing, offices and industries tends to pop up along highways, especially at exits and interchanges. Here is a classic example in the Montreal area: http://goo.gl/maps/0h0nb It doesn't take much to see how highways have shaped sprawl across the Montreal CMA. When new development appears along a highway, new trips will be generated. Buyers and developpers tend to make decisions based on induction and inference, and they rarely stop to consider future prospects for a transportation network.

 

Here's an example: Imagine two new lanes are added to a highway passing through a undevelopped stretch of land within an urban agglomeration. Let's even throw in a new exit or two for good measure. Developpers will be attracted to the land because it will provide their customers with quick and easy access to the highway network. Today, we know that performance increases along urban highways tend to last for 5 years maximum, on average. So for those 5 years following a highway widening, performance will be fast, and new houses will be built. Folks will buy up those houses and start living there. Development will occur for as long as performance of the road network is adequate. Here's the problem though. Let's say the highway widening added 20,000 vpd of capacity, and let's say 8,000 new residents move into the area over those 5 years. According to the 2008 Montreal OD Survey, on average those category of residents will use the highway on average several times per day, but let's be generous and assume only 2 trips will be made per person. That's 16,000 vpd of new usage -- from the new sprawl alone. Now when you consider the other factors I mentioned, plus toss in the other land uses, like commerical (say, a new Dix30-style mall) and industrial (some development lining the highway, as we so often see) our timid 16,000 vpd estimate easily ramps up to 40,000 vpd and beyond. What you end up with is even more congestion than you initially had, because people were "fooled" into thinking the new and improved highway would last like that forever. In reality, it's gone in 5 years or less.

 

In the early years, many deniers tried to pick apart research findings and look for mistakes. Even today, many deniers will often cite the UC Berkeley study from 1973-1990 which found that a 1% increase in capacity was met with a 0.9% increase in volume in under 5 years. They claim that the study didn't use enough data and therefore it's all wrong. Deniers often act like this is the only study we've ever done. The problem is, hundreds of new studies have been performed since then, with extremely reliable data using advanced techniques and the most cutting-edge computer software. With every passing year, the already-enormous mountain of evidence grows further still. To deny induced demand today, with everything that we've learned, is like denying that humans ever set foot on the moon.

 

I actually think it'll be less. I'm guessing 10% absolute maximum. Then again, I would love to see the before and after figures.

 

You're absolutely right in thinking it'll be 10% or less. Honestly, the figure will probably be somewhere around 1-4%. I threw around an extremely generous 10-20% hypothetical to show that even if we condeded such a large reduction, it still wouldn't matter.

 

And yes, you're correct in stating that many things can and will affect transportation models.

Classic road engineers, such as the ones we have at the MTQ, tend to look at very static models that don't take much into account. It's been like this for decades.

Urban transportation experts have been leading the revolution with integrated approaches that DO take into consideration all the factors you just listed, and many more.

The reason why most projections are poorly done and are way off the mark is because it takes an incredible amount of time and money to produce accurate figures.

You need to do precise traffic enumeration, you need rich disaggregate data (such as the data found in the Montreal OD Survey), you need good utility functions, you need all the socioeconomic data and trend forecasting info you can get your hands on, and that's just the tip of the iceberg. You have to create a statistically reliable model that correctly balances all these variables. It is a mountain of work, let me tell you. Traffic engineers operating on a meager budget can't and won't do all that.

Often their numbers are merely linear extrapolations, concocted in less than a day. I'm not joking.

 

In the end, even the most precise models crafted by teams of urban transportation experts over the course of 5 years with budgets of millions of dollars... won't be 100% accurate. You can never be 100% accurate. But I can guarantee you those models and projections are more accurate than the crap we get from the MTQ.

 

The moral of the story here is that everything we've learned over the last 60 years points to one conclusion: You can't build your way out of congestion, and even if you could, the side-effects would significantly outweigh any of the benefits. It's like trying to fight an ant infestation in your kitchen by leaving a bunch of food in your living room in the hopes of luring them away. In the end, you'll just end up with ants in your kitchen AND your living room. It's pointless.

 

The only viable solution is to densify, invest in transit, and reduce our automobile dependence. I'm not saying tear down all the highways (although some of them will need to go, eventually) all I'm saying is stop aggravating the problem by building new ones.

 

We need some cars and some amount of road infrastructure, but we're way passed just "some". We're in "way too much" territory.. The balance is tiltd 80-20 in the wrong direction, and we have a lot of work to do to try and bring it back to a sensible, sustainable equillibrium. The amazing thing is, we could stand to significantly bolster our economy too. On average, every dollar of transit spending more than doubles the economic output of a dollar spent on roads. Every dollar of transit spending generates more jobs too, because transit improvements are more labor-intensive (whereas road improvements are more material intensive.) This means more dollars in people's pockets, which means more spending and a stronger economy. Highways cost a lot to repair and maintain, and they generate sprawl which is highly inefficient and wasteful infrastructure-wise. The list goes on and on...

 

The evidence points to an undeniably resounding conclusion: our society is too auto-centric and auto-dependent, and we could stand to gain tremendously by moving towards a healthier transportation mix. Unfortunately, car culture is so ingrained in our brains that we get defensive whenever somebody takes up an inch away from cars. From the time we're infants, playing with toy cars, to the the time we're 16 and told that getting a car is a rite of passage, to all the cars we see on TV, in movies and song lyrics... we're just inundated with cars. It's easy to see why people get defensive and irrational. It's one hell of an uphill battle, let me tell you... but we'll get there. Change has already begun, and it will only accelerate.

Modifié 31 juillet 2012 par Cataclaw

[Né entre les rapides]

J'admets aisément que dans nombre de cas une augmentation de la capacité routière INDUIRA une augmentation de la demande (qui était jusque là inhibée par une manque de capacité). C'est particulièrement vrai quand la demande potentielle excède très largement l'offre--je pense souvent à l'expérience de Londres pendant de nombreuses années après la 2e guerre. Cependant, quand on considère le cas spécifique de l'A-25 (nouvelle portion--lien Montréal-Laval), je dois noter ceci:

1) J'ai toujours trouvé que les projections (débit de circulation au poste de péage) étaient TRÈS basses--comparez avec les débits actuels des ponts de l'A-15 et de l'A-13.--plus de deux/trois fois plus élevés.

2) En même temps, le réaménagement de l'intersection Pie IX-Henri-Bourassa entraînera une baisse de débit sur le pont--ce qui était un objectif recherché, et rendu possible par le nouveau pont de l'A-25. De la même manière, les pressions pour accroître le débit sur l'avenue Papineau s'atténueront.

3) Finalement, il s'impose d'analyser l'origine/destination des usagers, par ex. A-20 Jean-Lesage vers Boucherville/Ville de Québec, port de Mtl, parc industriel de Mtl- est, par opposition à des destinations au c-v de Mtl, lesquelles ne sont généralement pas souhaitables.

[Malek]

Cataclaw, ces 40000 "nouvelles" autos, ont enlevée de la pression ailleurs sur le réseau. Faut voir la vue d'ensemble.

 

Les chars ça se multiplie pas comme des mouches.

[Cataclaw]

Cataclaw, ces 40000 "nouvelles" autos, ont enlevée de la pression ailleurs sur le réseau. Faut voir la vue d'ensemble.

 

En fait, même pas. Selon le MTQ, le niveau de congestion n'a pas baissé sur les autres autoroutes menant à Laval.

Pour les 3 raisons que je viens d'expliquer, les 40 000 nouveaux déplacements sont en grande partie des ajouts.

[Malek]

En fait, même pas. Selon le MTQ, le niveau de congestion n'a pas baissé sur les autres autoroutes menant à Laval.

Pour les 3 raisons que je viens d'expliquer, les 40 000 nouveaux déplacements sont en grande partie des ajouts.

 

40000 déplacements out of thin air. Comme les 60000 déplacements au métros de Laval, out of thin air.

 

Tout ça c'est dans un tout, il n'y a pas eu 40000 résidents qui ont élus domicile à Laval et rive nord en si peu de temps, faut pas charier.

[Monsieur_MA]

Les chars ça se multiplie pas comme des mouches.

 

Ptete ben qu'oui. La génération spontanée s'appliquerait-elle aux voitures?

 

Une nouvelle route est construite et hop!

Quelques années plus tard elle est pleine.

Modifié 1 août 2012 par Monsieur_MA

[Cataclaw]

40000 déplacements out of thin air. Comme les 60000 déplacements au métros de Laval, out of thin air.

 

Tout ça c'est dans un tout, il n'y a pas eu 40000 résidents qui ont élus domicile à Laval et rive nord en si peu de temps, faut pas charier.

 

Ce ne sont pas 40000 résidents qui viennent de déménager à Laval soudainement.

Chaque vpd = 1 véhicle per day. Un déplacement qui s'est fait à travers le pont. Ce ne sont pas 40 000 nouveaux chars de vendus...

Va lire mon post un peu plus haut. J'ai tout expliqué ça en détail. Le 40 000 net à travers la somme des ponts Laval-Mtl ne vient pas de nouveaux résidents uniquement. C'est presque entièrement des gens qui font des déplacements qu'ils ne choisaient pas de faire avant, et des gens qui changent leurs destinations.

Modifié 1 août 2012 par Cataclaw

[Né entre les rapides]

Il me semble que les déplacements incluent les deux directions. J'en parle parce que j'ai vu bien des cas de congestion en direction de Montréal en après-midi, pas sur ce pont, mais L_H Lafontaine et Champlain.

 

Un autre point qui m'intrigue: s'il y a tant de véhicules supplémentaires qui se rendent à Montréal, oû donc stationnent-ils? Et cela veut-il dire qu'il y avait une capacité excédentaire de stationnement, ou encore que les résidents de l'Ile se sont tous mis aux TEC pour laisser la place libre aux gentils banlieusards? Ceci dit parce que je suis convaincu que si l'on veut sérieusement limiter la circulation automobile au c-v et les environs (par ex. Plateau), qu'on commence par limiter le stationnement (pour tout le monde), plutôt que d'accuser les banlieusards. Et pour ce qui est des destinations excentriques sur l'Ile proprement dite...devinez ce que j'en pense!

[Cataclaw]

Il me semble que les déplacements incluent les deux directions. J'en parle parce que j'ai vu bien des cas de congestion en direction de Montréal en après-midi, pas sur ce pont, mais L_H Lafontaine et Champlain.

 

Un autre point qui m'intrigue: s'il y a tant de véhicules supplémentaires qui se rendent à Montréal, oû donc stationnent-ils? Et cela veut-il dire qu'il y avait une capacité excédentaire de stationnement, ou encore que les résidents de l'Ile se sont tous mis aux TEC pour laisser la place libre aux gentils banlieusards? Ceci dit parce que je suis convaincu que si l'on veut sérieusement limiter la circulation automobile au c-v et les environs (par ex. Plateau), qu'on commence par limiter le stationnement (pour tout le monde), plutôt que d'accuser les banlieusards. Et pour ce qui est des destinations excentriques sur l'Ile proprement dite...devinez ce que j'en pense!

 

D'accord avec toi, Né entre les rapides. Il faut revoir la stratégie de stationnement.

 

En ce qui concerne les déplacements, les destinations ne sont pas tous le centre-ville. Je n'ai pas les chiffres, mais je suis certain qu'un grand nombre de déplacements passent par l'ile pour se rendre à Longueuil/la rive sud... surtout dans l'axe de la 25. C'est possible de partir de Laval, traverser Montréal et se rendre à Longueuil en 10 minutes. Il a certainement des destinations à Saint-Laurent, Anjou, etc.

[ToxiK]

D'accord avec toi, Né entre les rapides. Il faut revoir la stratégie de stationnement.

 

En ce qui concerne les déplacements, les destinations ne sont pas tous le centre-ville. Je n'ai pas les chiffres, mais je suis certain qu'un grand nombre de déplacements passent par l'ile pour se rendre à Longueuil/la rive sud... surtout dans l'axe de la 25. C'est possible de partir de Laval, traverser Montréal et se rendre à Longueuil en 10 minutes. Il a certainement des destinations à Saint-Laurent, Anjou, etc.

 

 

Il y a de très gros pôles d'emplois à Anjou et Saint-Laurent.