I suspect there are alternative hypotheses that could be strong or stronger. My first guess would be direction ~= f(ratio of parking_lot space to average_car_s

I suspect there are alternative hypotheses that could be strong or stronger. My first guess would be direction ~= f(ratio of parking_lot space to average_car_size). Whenever we drive in the USA, the parking lot space, even accounting for the larger automobile, seems massive compared to the spots we park in SE Asia. As well, I've seen in various countries specific prohibitions against head-in/back-in parking. It also feels like an index that while it 'fits' today is not going to change while the underlying productivity measures might be changing. IE: people park one way or another out of habit, not out of a link to their recent or leading productivity.