An article about highway projects in the Pacific Northwest caught my attention.
But this shiny new document omits important considerations in predicting the future impacts of I-5 expansion on this long and constrained corridor, one that would have received little attention a decade ago. It is an omission that would not have been made, but its omission is very conspicuous. My thumb hurts now. This almost completely avoids the concept of induced demand, where additional road capacity encourages more journeys, as road users seek to take advantage of faster travel, and ultimately It negates many of the promised benefits of the addition, especially congestion relief. .
Opponents of a new, larger bridge connecting Vancouver, Washington, and Portland, Oregon, say it will increase the number of people using the bridge. Project supporters assume the number of cars crossing the bridge will not increase. That seems a little strange.
Consider the following analogy. Movie theaters are popular and often full. The management committee is considering adding more movie theaters. One group argues that expanding movie theaters could attract more customers. The other group argues that expanding theaters will not increase movie attendance. Which of these groups would you expect to support expansion, and which would you expect to oppose it? Can you see the problem?
Of course, there are many differences between movie theaters and bridges, so we promise to take a look at those differences. But the first thing I want people to think about is how strange it is that opponents of a freeway expansion project are the same people who believe it will induce more demand for that service. .
Supporters of bridge expansion are typically political leaders who want to respond to the wishes of their constituents. There are two types of voters: those who pay attention to the bridge expansion issue and those who do not. I suspect there is a strong correlation between voters who support bridge expansion and those who are already using the bridge, perhaps simply because they know more about the situation than other voters. are. When proponents of bridge expansion deny demand stimulation, they are implicitly suggesting that all the benefits go to existing users in terms of reduced traffic congestion. However, such an outcome seems highly unlikely since it would violate the law of demand. When something becomes cheaper (in terms of opportunity cost of time) due to an increase in supply, it leads to an increase in the quantity demanded. There will also be induced demand.
Opponents of bridge expansion also have an incentive to cater to the voters most interested in the issue. They may want to argue that bridge widening would be of no use because it would induce too much additional demand and traffic congestion would be as bad as before. But that argument also violates the law of demand. If traffic congestion is not alleviated, what will induce new drivers to start using the bridge? I’m not claiming that it prevents it, but I’ve seen others make that claim).
One essentially argues that the demand curve is perfectly vertical; the other implicitly argues that the demand curve is perfectly horizontal. In fact, the demand curve slopes downward.
So what’s the answer? Should the bridge be built?
Elsewhere in the article, the authors make clear that opposition to bridge expansion is related to environmental concerns. Ideally, Pigouvian tolls should reflect all kinds of transportation externalities, such as congestion, pollution, global warming, and suburban sprawl. Such tolls would make it easier to evaluate projects on a cost-benefit basis.
(But even then, other complications may arise, such as indirectly affecting the use of other roads that don’t have Pigovian tolls. So I don’t think Pigovian tolls on the bridge completely solve the problem.) I’m not suggesting that it will be solved, as it will make it easier to evaluate the pros and cons of a new bridge.
PS. In a previous post, I suggested that Vancouver, Washington, is an attractive place for libertarians. You can work in a state with no state income tax (except for capital gains) and shop in a state with no sales tax. The Pacific Northwest also tends to be quite liberal when it comes to social issues like drugs, abortion, and the right to die. So perhaps we should also consider whether this bridge will allow us to expand our little libertarian paradise in Southwest Washington.
This is a photo of Vancouver with beautiful Mount Adams in the background.
