There is 4 lanes, you can remove one or two and set train tracks which don’t have a lot of constraints compared to cars due to train wheel being steel and having better adherence.
People who still need car for whatever reason can use the remaining lanes and have less trafic since train are a lot more efficient than car at moving people.
If you are woried about the swap I’m sure care exaust and tires particles which are know to damage environement a lot. Trains are electric so at least polution will be localized near power plants and thoose can be eventualy replaced by renewables.
In case this is in good faith :
There is 4 lanes, you can remove one or two and set train tracks which don’t have a lot of constraints compared to cars due to train wheel being steel and having better adherence.
People who still need car for whatever reason can use the remaining lanes and have less trafic since train are a lot more efficient than car at moving people.
If you are woried about the swap I’m sure care exaust and tires particles which are know to damage environement a lot. Trains are electric so at least polution will be localized near power plants and thoose can be eventualy replaced by renewables.