The construction of streets throughout the twentieth century was largely based on the premise that more infrastructure eases traffic. Evidence shows, however, that instead of reducing congestion, building more roads actually increases traffic. Reducing drive times makes driving more convenient; consequently, coupled with the status-symbol appeal of private vehicles, people tend to make more trips by car. A recent study by researchers at the University of Barcelona analyzed data from 545 European cities between 1985 and 2005, confirming that two decades of efforts to expand road capacity led to an increase—rather than a decrease—in vehicle traffic, failing to alleviate congestion.
In contrast to traffic generation, “traffic evaporation” is a phenomenon where traffic disappears when road space is reallocated from private vehicles to more sustainable modes of transport, such as walking, cycling, and public transit. Although traffic evaporation has been studied and well-documented for over 20 years, most decision-makers and opinion leaders still believe that reducing traffic lanes worsens traffic.
