So why have two lanes over 1 lane? If you have two roads merging for a few miles then splitting, going to one lane will cause a bottleneck
Obviously there is a point where an extra lane is useful and a point where dropping a lane is useful.
Other questions you ask - when the road was built did traffic in nearby roads drop, did you get fewer cars rat-running through residential areas, is the increased traffic because of closure of rat runs making travel in the congested freeway more attractive despite the lack of capacity.
There’s other long term questions too, did the freeway allow people to live further from their destination, encourage longer or more frequent journeys, although the answer to that could be positive or negative depending on your viewpoint. Eventually you get to asking “is the motor car a good thing or a bad thing”.
Obviously there is a point where an extra lane is useful and a point where dropping a lane is useful.
Other questions you ask - when the road was built did traffic in nearby roads drop, did you get fewer cars rat-running through residential areas, is the increased traffic because of closure of rat runs making travel in the congested freeway more attractive despite the lack of capacity.
There’s other long term questions too, did the freeway allow people to live further from their destination, encourage longer or more frequent journeys, although the answer to that could be positive or negative depending on your viewpoint. Eventually you get to asking “is the motor car a good thing or a bad thing”.