This really shouldn’t be necessary to post (certainly not to most readers of PT), but apparently it’s needed when those running for office in Vancouver don’t get that trying to reduce congestion by increasing the efficiency of the road network – whether through widening or counterflow lanes – isn’t going to work:
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The “fundamental rule” of traffic: building new roads just makes people drive more
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This article from Vox begins with a stunning revelation. Well, it would be if it wasn’t so consistent with the ‘fundamental rule.’
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Decades of traffic data across the United States shows that adding new road capacity doesn’t actually improve congestion. The latest example of this is the widening of Los Angeles’ I-405 freeway, which was completed in May after five years of construction and a cost of over $1 billion. “The data shows that traffic is moving slightly slower now on 405 than before the widening,” says Matthew Turner, a Brown University economist. …
He and University of Pennsylvania economist Gilles Duranton call this the “fundamental rule” of road congestion: adding road capacity just increases the total number of miles traveled by all vehicles. …
In an influential 2011 paper, they looked at the total capacity of highways in each metropolitan area in the US and compared it with the total number of vehicle miles traveled.
They found a one-to-one correlation: the more highway capacity a metro area had, the more miles its vehicles traveled on them. A 10 percent increase in capacity, for instance, meant a 10 percent increase in vehicle miles, on average. But that, on its own, wasn’t conclusive. “This could just be telling you that urban planners are smart, and are building roads in places that people want to use them,” Turner says.
So, to try to isolate the effect of building roads, the economists then compared changes in highway capacity between 1983 and 2003 to the changes in vehicle miles traveled. “Again, we saw a direct one-to-one correlation across all cities,” Turner says. This correlation also held up when the economists compared roads within cities: added road capacity consistently led to more driving. Still, even this wasn’t conclusive. It could, after all, simply be a function of planners making good decisions — perfectly anticipating unmet driving demand.
As a final step, then, the economists tried to isolate a few different sets of roads that were planned with no regard to current driving patterns — newly built roads that were part of the original 1947 interstate highway plan (which was based on 1940s population levels, not 80s and 90s), and those that followed 19th century railroad rights-of-way, or 18th and 19th century routes taken by explorers. “We saw exactly the same effect here too,” Turner says.This finding has since been replicated with Japanese and British data. It doesn’t seem to be an effect of optimized planning. Again and again, more roads lead to more driving — with no reduction in congestion.
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However, if your goal is reducing traffic congestion, this research shows that adding road capacity won’t do it. But there is a way: congestion pricing.
More here.
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Now that would be a discussion worth having in an election campaign. As far as I know, no party has put it on their platform.
“The “fundamental rule” of traffic: building new roads just makes people drive more”
Unless you toll or road-price accordingly. 😉 I’d support major improvements to roads, or even increasing capacity (?pattulo) if road pricing was in place.
Exactly. Toll roads until the (remaining) traffic moves at desired speeds. Car use is far FAR too cheap in most cities, incl. Vancouver. Which mayoral candidate is pushing this message ?
Where is the vision here ?
An economist put it to me: ‘increase the supply and decrease the cost. This unfortunately incentives demand to the point where supply is insufficient.’ If civil engineers were military strategists, they would still be digging the Maginot Line.
Hi Gord- Thinking of traffic here in Wuhan China with masses of new freeways… Is Christy cool on the transit ref because she needs to keep cars flowing to pay for the Port Mann and soon the Massey bridges? P
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Measuring “congestion” is a political game.
Politicians use it to appeal to voters because it has a “me” quality to it.
It will improve “my” wait , “I” won’t have to wait as long, etc. etc.
Me. Me. Me. Voters love that.
The problem is that with ever-changing variables and metrics – increasing population, shifting travel patterns for shopping and jobs, and of course the tried and true “demand will expand to fit capacity” (no one will let something sit unused).
The real measure shouldn’t be “reducing congestion” (making it better for “me, me, me”) – it should be:
“increased throughput”
(even if qualitatively its takes the same time or even a slower time)
– and which reflects the impact of the project across all users at a regional level.
Reblogged this on SalvoLomas and commented:
El trafico Inducido, ley fundamental del trafico
Notice that this rule apply also to Transit.
Louis Dausset, on Paris budget Committee was stating as soon as 1909:
“When we built the Metropolitan and encouraged the development of trams, we gave our citizens and visitors a taste for moving around…So underground transport does nothing to reduce surface movement in Paris; on the contrary, it multiply it”
see source in https://voony.wordpress.com/2011/12/12/impressionists-on-the-parisian-boulevards/
Why not live close to where you work even if it means relocating?
Why not work close to where you live so it doesn’t mean relocating?
Why do we have the idea that commuter congestion is an issue that government can solve with hectares of concrete or kilometers of steel rails?
Why can’t the “congestion problem” be solved with mixed land use planning so that we have the choice to live and work in the same area?
Many reasons .. such as:
because people change jobs,
because people have spouses,
because people have kids,
because folks have parents or families in certain parts of town and wish to be close,
because certain jobs exists only in certain areas,
because employers sometimes change locations,
because work is only one aspect of one’s life,
because some parts of town are nicer to live in than others,
because some folks prefer leafy suburbs over dense condo living .. ..
The counter flow argument only works if the number of cars remains constant.
When the counter flow is introduced, commuters switch from other modes of transit to driving. They continue to do this until the volume of drivers pushes the road network back to a new saturation point, whereby it is no longer faster to drive than use other modes of transit. The end result is that within a very short time the roads are clogged again.
The only “quick” way to reduce congestion is to build high capacity fixed link public transit, and this option is not a municipal jurisdiction, it is a provincial one. The province is still yet to elaborate there referendum on a transit strategy for the GVRD.
http://gitanoafricano.wordpress.com/2014/08/04/on-a-road-to-nowhere-regional-comprehensive-transit-stuck-in-traffic/
I disagree. The only effective way to reduce congestion is to price it .. and the price has to go up until the congestion stops. Starting at $5, then $10, then all the way to $100/crossing from 6-10 am on Lionsgate bridge, or any other choke point in the city, I bet congestion will disappear quickly. Far cheaper than building public transit alternative which takes millions or billions and takes years !
Congestion just means we pay with time, rather than money.
[Of course, alternatives will have to be eventually built, say a subway from W-Van or N-Van or a high capacity bus in lieu of the $100/car toll .. plus a parkade I guess as some folks still want to drive to the parkade .. then take the bus]
Reblogged this on GitanoAfricano.