If you built a new highway or expand the capacity of an existing highway, you have only a short time before the new or expanded highway is just as congested as before. It's called "modal split," and it's the nightmare of highway engineers.
Once you hit a tipping point, you get more bang for the buck by expanding transit, not trying to keep up with the highways. Rail-based transit has its uses in certain corridors of high density where it functions as a trunk feeder, permitting people to finish their trip by bus at a transit center node or by car at a park-and-ride node.
The Puget Sound region has been moving in that direction since Boeing started hiring again in 1984 and with the arrival of the software industry. If you read the article closely, you'll see that they're suggesting patches to existing highways rather than the broad brush of building new freeways, SR-167 and SR-509 excepted.
I believe that Transit proponents are their own worst enemies.
Most of them seem blind to the fact that much of the population knows global warming is a hoax, and thus any argument that utilizes global warming as a reason to support transit is at best a waste of time and at worst is a convincing argument to oppose the transit proposal.
The percentage of utilization numbers that seem to be entirely wish based appears to me to approach unity. The difficulties of convincing people to use transit instead of driving is always underestimated. High-speed rail is the worst, very few of those that drive between the destinations are going to take the train instead of driving just because it is a train. High speed rail will take it’s passengers from the short haul aircraft.