This commentary was published in the Boston Globe on November 6, 2006

THE SAGAMORE ROTARY is gone, and the rejoicing is near universal. Killing a bottleneck that delayed traffic to and from the beaches of Cape Cod certainly seems worthwhile, even if the execution required $33 million. The engineers have triumphed. Nothing could be more straightforward: When you see a bottleneck, open it up. Visions of convertibles dance through our heads — top down, Truro here I come!

Alas, I cannot join the cheering chorus, even though I have spent hours sitting in traffic on Route 6 trying to get home.

Getting rid of the rotary won’t eliminate the traffic problem any more than skipping dinner every night will make you skinny. You have to ask the economist’s favorite question: And then what? If you skip dinner, you’re probably going to end up eating more at breakfast and lunch. As for the rotary, getting rid of it encourages a lot more people to go to the Cape who didn’t go before.

Yogi Berra once said of a restaurant, “Nobody goes there anymore; it’s too crowded.” Same with the Cape. It’s the traffic that deters even more people from going there on any given Sunday. Get rid of the traffic, and more people suddenly find it attractive.

Think of my dad. He hates traffic. Growing up in Lexington, we never went to the Cape on a summer Sunday. My dad didn’t want to sit in traffic getting there or coming home. We went to Revere. Piece of cake. Not as nice as the Cape. But when you considered the hassle, the ease of Revere outweighed the elegance of the Cape for my dad.

Getting rid of that rotary makes Cape Cod more attractive to my dad and thousands like him. As those folks make the trek to the suddenly more convenient Cape Cod, the roads into and out of the Cape — and on the Cape as well — are going to get more crowded. They have to get more crowded. Until they do, someone else will go to the Cape who previously went to Revere or Gloucester or the Jersey Shore because getting to the Cape was too inconvenient relative to its rewards.

Getting rid of the rotary can’t solve the traffic problem because it doesn’t change the underlying cause of the congestion: the relative scarcity of sand and surf next to magnificent dunes.

A lot of wonderful scarce things are expensive. Think box seats at Fenway on a perfect night in June, Van Gogh’s paintings, or a condo overlooking Central Park.

But sitting on the beach at Cape Cod is wonderful and scarce and relatively cheap — cheap measured by the out-of-pocket costs of a day trip. So more people want to enjoy the Cape than there is room for them on the Cape’s roads and beaches. Removing a rotary makes that problem worse, not better. It removes one of the costs of enjoying those beaches. So other costs emerge in response, though no one wants it that way.

Next July or August, there will be a new bottleneck. I’m not sure where it will be, but I’m confident it will be there. The only question is how bad it will be.

It’s a Catch-22. One possibility is that the new bottleneck will be just as bad as the Sagamore Rotary. In that case, the project accomplishes nothing. The second possibility is that it won’t be quite as bad. But that means more people on the Cape. That’s nice for the newcomers. But it also means more congestion on Route 6 when it rains and thousands of people are trying to find something to do with the kids. It means more traffic on the side streets. It means parking will be even worse in Provincetown. It means less space at the beach on a cloudless Sunday in July.

All that for the bargain price of $33 million.

I’ll see you next summer. We won’t be alone.