More roads = more traffic. This is known as “Induced Demand”. Studies have shown that expanding road capacity often results in a proportional increase in traffic volume, negating the initial benefits.

Expanding road infrastructure encourages car usage, leading to higher greenhouse gas emissions and environmental degradation. That’s a bad environmental impact.

Investing in public transport yields many more advantages, says UN-Habitat:

> Efficiency: Public transport moves more people with less space and energy, cutting down on traffic and improving air quality.

> Social Inclusion: Public transport makes cities more accessible for everyone, promoting social equity and inclusivity.

The diagram below shows 3 schematics of a bottleneck on a highway into a city. The first shows the problem (cars entering a city), the second the typical solution (expanding the highway), the third a solution that shifts drivers to other modes. (Urban Cycling Institute)