To help explain why toll lanes might not be the great solution to traffic congestion many believe them to be, Timothy Lee goes to an unexpected place to draw parallels: your local supermarket.

Supermarkets are a good analogy, suggests Lee, because they operate in a free market, are ruthlessly efficient, intensely competitive, and employ ‘lanes’ (checkout queues)… but they don’t use congestion pricing. The reasons why they don’t, he says, can also be applied to traffic congestion:

First, we have strong and sophisticated social norms, cultivated since we were young children, for waiting in lines. This bit of self-organization is cheap oakley sunglasses extremely important for the smooth functioning of civil society. We see waiting your turn as an obligation we have to one another, and therefore not as an obligation that a supermarket or transportation agency can waive in exchange for a cash payment. I suspect customers would see people using a tolled checkout lane as breaking an implicit social contract.

More importantly, customers would be suspicious that the supermarket was deliberately under-staffing the free lanes to gin up demand for the express ones. […] In the low-margin grocery business, it would be a pretty effective way for a manager to pump up his short-term profits, while the long-term harm to the store’s reputation would be hard […] to quantify.

This latter concern seems particularly relevant to the case of toll roads. The revenue-maximizing pricing schedule is not the same as the congestion-minimizing schedule. An effective congestion-pricing scheme might generate relatively little revenue if people shift their driving to off-peak times (which is the whole point). The operator of a monopolistic toll road will face a constant temptation to boost revenues by limiting throughput on free lanes and jacking up the off-peak toll rates. The widespread voter perception that cheap oakley sunglasses they’ve “already paid for” many tolled roads through other taxes isn’t exactly right as a matter of fiscal policy, but I think it’s based on a sound intuition: there’s no reason to think the political process will set tolls in a way that’s either fair or economically efficient.