Infrastructure changes happen anyway. Roads get widened, reorganized, and maintained all the time. It's just a question of what the available space should get allocated to.
The Netherlands didn't change their infrastructure overnight. They changed the infrastructure standards instead, and whenever a road needs to be redone, they upgrade it to the new standards. This took ~30-50 years, but had amazing results.
Of course it can be done faster if you want, and then it will be more expensive as well. But if you want to do it cheaply, you can absolutely get a very high ROI this way.
