Building more highway lanes will cause more people to drive (induced demand), so building more lanes won't fix traffic.
Is this really fallacious? I'm asking because while I don't know the topic personally, I have some friends who are really into city planning. They've said that this is something which is pretty much unambiguously accepted in the literature, now that we've had the time to observe lots and lots of failed attempts to fix traffic by building more road capacity.
A quick Googling seemed to support this, bringing up e.g. this article which mentions that:
In this paper from the Victoria Transport Policy Institute, author Todd Litman looks at multiple studies showing a range of induced demand effects. Over the long term (three years or more), induced traffic fills all or nearly all of the new capacity. Litman also modeled the costs and benefits for a $25 million line-widening project on a hypothetical 10-kilometer stretch of highway over time. The initial benefits from congestion relief fade within a decade.
This post is a container for my short-form writing. See this post for meta-level discussion about shortform as an upcoming site feature.