The current population of Columbus is less than 1,000,000 for the city proper and about 1.8 million for the metro area.
2.2 million for the metro area projected to be 3.15 million by 2050. The way this stuff works, you better get the roads in now because once it's built out, no way will you be able to jam a freeway in there
The source I looked at actually said less than 1.8 million. I rounded up. At any rate, an increase of almost 50% by 2050 seems quite unlikely, but 2050 is still about 3 decades away, not 1. I agree that something needs to be done and the sooner the better, but there's no need to exaggerate or sensationalize the facts and figures, which this writer seems to have done. I drove through Delaware County 40 years ago and traffic was terrible then. I'm thinking this should have been addressed in the 1960's or earlier.
https://www.macrotrends.net/cities/22963/columbus/population