The other day I saw a pedestrian signal with a countdown timer (and raced across the road because there were only a few seconds left). But overall they're a good idea, right?
We find that although countdown signals reduce the number of pedestrians struck by automobiles, they increase the number of collisions between automobiles. We also find that countdown signals caused more collisions overall.
I'm usually a 'transparency is good' kind of person, but this is an interesting conclusion:
The findings imply welfare gains can be attained by revealing the information to pedestrians and hiding it from drivers. We conclude that policies which increase asymmetries in information can improve welfare.
I shall hereafter refer to that as the 'keep the missus guessing' principle.