At least now the 4 hours you spend in traffic every day can be useful — catch up on some sleep, check your email, train your car's AI by playing "I spy"...

That's at the heart of the problem. Once traffic time is lower 'cost', then people will likely immediately start spending that savings. A one hour acceptable commute becomes shifts to 4 hrs being acceptable, and you get maybe 4x more traffic into the same commerce centers.