[FeepingCreature]

That's not a reason to not improve infrastructure anymore than "the more chocolate we produce the more people want to buy chocolate" is a reason not to make chocolate. It just shows you're ludicrously underserving demand.

[supertrope]

Efficiency matters. If allocating 100 million currency units to widening a highway from 5 lanes to 6 lanes improves people/hour capacity and quality of life less than other solutions, the other solutions should be chosen. In addition to diminishing returns on the way we’ve always done it, there’s a hard limit of about 2000 cars/hour/lane.

Chocolate is not free at the point of use but roads usually are. Without price signals or other limits people over-consume resulting in a shortage and people paying in time.

[lotsofpulp]

Hence an easy solution to traffic is increase the cost of driving. Which Seattle already has dynamic tolls which change in price:

https://www.wsdot.wa.gov/Tolling/TollRates.htm

[FeepingCreature]

The fact that it induces demand makes it more efficient, not less.