Paul Jacob has been writing and recording his Common Sense radio commentaries for years, first for U.S. Term Limits, then for Americans for Limited Government, and now for The Sam Adams Alliance. I mentioned a three-year-old Common Sense piece last week in a blog entry I wrote about term limits here in Missouri.

Now, the Show-Me Institute has turned up in Common Sense for the first time:

[A] suggestion by a think tank in Missouri might cause a few heads to shake. In disbelief.

The idea? Make the Poplar Street Bridge a part-time toll bridge.

Southern Illinois University economist R. W. Hafer, writing for the Show-Me Institute, argues that another bridge might not even ease congestion. Why? By making commuting easier it would effectively lower the cost of commuting. When costs go down, demand grows, in this case even taking people off of public transit to drive their cars.

Putting a price on bridge travel, on the other hand — especially if the prices rise when demand rises — would encourage commuters to economize, and thus make the trek over the Mississippi easier for all.

This Common Sense excerpt refers, of course, to an op-ed written last month by Show-Me Institute scholar R.W. Hafer. He takes price theory, which works so well for goods and services in the private sector, and applies it to roads and traffic patterns. It’s a good idea, too often overlooked by people who are used to using roads for free. But, as I pointed out last month in a piece about ticket-scalping, goods that are priced below market value still have a high cost — usually in terms of time spent waiting in line. In this case, it’s a high cost in terms of wading through rush hour traffic congestion. Ultimately, no goods are free. The important thing is not to make prices artificially lower, but determining the most efficient way to distribute real-world costs.

It’s against federal law to charge a toll on roads constructed with federal gax taxes, and the Missouri constitution currently disallows using state funds to build toll roads, so we can’t just slap a few toll booths on existing roads and bridges without somebody passing some legislation first. But getting legislation enacted isn’t our job — we simply conduct research and educate people about our findings, and the value of free-market mechanisms in public policy.

In other words, we traffic in good ideas. So does Paul Jacob.