This is not exactly true. Demand for traffic is not static and just sitting there, waiting to be fulfilled. Demand indeed can be induced by an offering. If you know that from point A to point B, commute times will be X, you think twice about moving to point A if you work at point B, or taking up a job at point B, if you are already living at point A. But if due to road construction and adding a new lane, traffic times will lower to X-t, suddenly living at A and working at B will become viable, people living in A will work at B, and traffic between A and B increases, and travel times will no longer be X-t, but increase, until they reach equilibrium again at X, which was the prior cutoff point.
The same happens to businesses. A business incorporated at A might think twice about offering services at B, if roundtrip times are X. But if an additional highway lowers the travel times to X-t, it becomes a business case, until the additional demand has eaten up the advantage, and we are back at X times.