There's lots of constructive arguments to be had about the relative benefits of investment in roads vs. rail vs. whatever, and tons of good criticism to level against subsidies and un-taxed externalities (for all those options). But arguments complaining about the "endless cycle" of building useful things that subsequently get used are silly. This lowers the quality of the conversation about public transit, making it more difficult to convince others of the relative merits.
If public transit or bike lanes would provide a better benefit for the same cost, then I would support them. But that's a separate and complicated discussion. Instead, this article seems designed to mislead people into thinking that expanding roads has literally no benefit, when obviously it does even if congestion remained the same (which it doesn't).
Maybe I'm too cynical...
Adding extra capacity can even make the problem worse because of what happens when increased capacity meets lower capacity. Human driver are terrible at going from two lanes down to two. You could say that this is bad design but in cities especially there are constraints that you can't really design around very easily without destroying massive parts of the city. This was done in the past to allow highways to penetrate right into cities but those highways just slowed to a crawl.
As for cost effectiveness bike lanes are a lot cheaper than extra road lanes and very much cheaper than elevated highways. Bus rapid transit is also extremely cheap. That's before you start looking at other cost benefits such as increased health for more exercise and less pollution.
That seems to argue in favor of the expansion. The 10% road increase may only lead to a 4% decrease in car density, but that could be enough to bring traffic out of standstill.