The real world isn't A/B tests. No government is going to spend millions on equipment and infrastructure on a congestion zone because some engineers are like "Let's just test this out. I have done zero research on what could possibly happen, but it would be fun to see what the results are."
When you write it out like that, it seems to make total sense! But then you read grant proposals that get funded - in things like the social sciences and humanities, and even conventional science and health - millions of dollars essentially just throwing darts to see what sticks.
