Katy Freeway, outside of Houston, has come to symbolize the epitome of American auto culture. After a nearly $ 3 billion expansion project completed in 2008, the highway spans 26 lanes at its widest point (although there is some dispute whether you should count the peripheral roads on the façade).
But it also came to symbolize something else: a transport phenomenon called induced demand – the idea that building more infrastructure will only encourage more demand. In this case, the offer is for highways, and the demand is increasing for drivers. Meaning: If you build more tracks, more drivers will fill them.
The concept of induced demand has existed since the 1960s – almost since the beginning of the federal road system – and has been proven by several studies since then. But it has not yet stopped the tide of large and expensive road infrastructure projects as a curative for congestion.
Transport is currently the leading cause of greenhouse gas emissions in the United States, and this is largely driven by the use of single-person cars. Most US cities revolve around the car, and because of that, it is difficult to reform another system geared to public transportation or walking. But there are some policies that can get more people off the road in the short and long term.
In this video, we explain what happens after the expansion of a highway and where new drivers come from to fill new lanes.
You can find this video and all Vox videos on YouTube.