> Overall, VKT in the US doubled from 1983 to 2003, from 7,700 VKT to 15,900 VKT for interstate highways. For major urban roads, a similar pattern occurred – VKT went up from 15,000 to 30,000. In the same time span, the number of lane kilometers of interstate highways remained basically constant, while on major urban roads, it went up from 3,800km to 6,500km.
I don’t know how someone can trot out this stat and then claim with a straight face that new lanes cause congestion. What this states is that car traffic doubled over a 20 year period, and it doubled whether lane capacity increased (cities) or not (interstates).
Basically, an extra lane temporarily reduces congestion. The main cost of congestion to road users is time. Since now it's faster to travel, you're more likely to do an extra car trip. You continue taking extra car trips, until the cost in time is the same as pre-road expansion.
The question then is are the extra car-trips valuable.
In fairness, I have not read the 37 page paper yet. Maybe the paper makes a more compelling case than the summary article.
The demand fills capacity is not a good rule of thumb either, from an economist's perspective. Shame on you. Many multi-lane highways are rather empty, why? Many roads are basically never used, why?
Lanes (transit corridors) are a river of money (funnels). When you have populations that are exchanging goods, jevon's paradox fills lanes to increase capital velocity that scales beyond the average value of infrastructure. Infrastructure cost is balanced against a perceived value, which is always skewed toward the larger (poorer) part of the population.
In this case, it's not a paradox at all that capital self-generates demand for this space. This also explains why some corridors are emptied as capital flees a locale.
The authors seem to suggest that demand for roads is infinite, as expanding roads merely increases the number of trips people choose to make, thus infinite expansion will result in infinite trips.
These analyses always appear to me as if they are without any understanding of how humans actually behave, resulting in nonsensical nonsense "laws".
Agree. They literally claim this with “increasing lane kilometers by 1% will increase VKT by 1.03%” but subtly acknowledge that this fundamentally doesn’t make sense with the hand-wavey “any feasible increase in roadways will have no impact on congestion”. Keyword feasible.
The real law doesn’t seem to be that congestion rises to meet capacity but that no one will ever fund enough road expansion to make peak congestion low.