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A Natural Experiment

A beautiful natural experiment has just been set in motion. The New York Times reports:

For decades, summer weekends on Cape Cod have been filled with sunblock, sand and backups that last for miles.

The source of those tie-ups, the Sagamore Rotary — a complicated
traffic circle that drivers had to navigate to pass over the Sagamore
Bridge and onto Cape Cod — became history on Friday when the four-lane
road that goes right to the bridge opened to traffic from all
directions. Gov. Mitt Romney
commissioned the new road, called a flyover, in 2003, and said he would
“resign in shame” if it was not complete by the end of his term; he is
not running for re-election this year.

The Times’s headline summarizes the optimism nicely:

New Link Makes Road to Cape Cod Clear Sailing

Well, maybe in October. But economics suggests that the Rotary (which I have navigated many times) is not the source of the traffic problem on Cape Cod. The source of the traffic problem is that the beaches of Cape Cod and the roads to visit those beaches have a monetary price of zero or close to zero. At a price of zero, in July and August, there is excess demand to travel to Cape Cod and enjoy those beaches. The result is congestion that cannot be solved by a traffic engineeer.

Reducing the congestion caused by the Rotary will simply enocourage more people to visit the beaches. Congestion will rise and that congestion will again ration the limited supply of beach access and space on the road. Congestion will soon return to the level that existed when there was a Rotary.

My prediction is that some time in July or August you will see articles in the Times and the Boston Globe expressing surprise that the removal of the Rotary did not seem to have the anticipated effect.

You can read more about the economics of congestion and Cape Cod here.


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