The great Tim Carney, the Washington Examiner’s muckraking Mozart, lays into Virginia Governor and alleged conservative Bob McDonnell for supporting a new raft of tax increases and infrastructure improvements:

The transportation bill McDonnell supports would hike sales taxes to 6 percent in Northern Virginia (up from 5 percent), rejigger the gas tax and index it to inflation and increase taxes on home sales. This tax revenue, along with more money from the general fund, will provide what the Fairfax Chamber of Commerce calls a “sustainable fund” for transportation, with the hope of alleviating traffic congestion.

But even if the plan fleeces ordinary people, they stand to spend less time in traffic. Right?

If you think all this new pavement will mean less congestion, consider these other supporters of McDonnell’s plan. The Virginia Automobile Dealers Association signed on, presumably expecting more people to buy cars if there are more lanes. The Home Builders Association and the Virginia Association of Realtors back the bill, too, foreseeing more homes in Loudoun and Fauquier counties. So you get more lanes, but also more commuters and more drivers. The result could be the same amount of congestion.

Carney’s suspicion is well-grounded in economic theory. The time we expect to spend in traffic is the price we are willing to pay for the convenience of using the roads at a given point each day. Increased capacity may simply mean more time spent on the road as more people use it. The previous equilibrium may be reached again.

As someone formally trained in economics, it is my vocational duty to disclose an even more dismal possibility: Braess’ paradox. If capacity is added to a network, such as a road system, the actions of the self-interested individuals using it may, under certain circumstances, actually increase transit times. As with any such economic theory, there is a ceteris paribus assumption: All else is assumed to remain equal. No construction of additional housing or increase in the user base. And both can be expected thanks to this plan.

To be clear, the mathematics behind this theory are far over my head, and estimating the risk in this case without specific information is virtually impossible. But real-world cases of this phenomenon have been observed. Virginians must steel themselves against the prosaic insult of injury compounded upon injury.