Thanks for the link, Rosemary. From The Atlantic.

Economists and ecologists sometimes speak of the “tragedy of the
commons”–the way rational individual actions can collectively reduce
the common good when resources are limited. How this applies to traffic
safety may not be obvious. It’s easy to understand that although it
pays the selfish herdsman to add one more sheep to common grazing land,
the result may be overgrazing, and less for everyone. But what is the
limited resource, the commons, in the case of driving? It’s attention.
Attending to a sign competes with attending to the road. The more you
look for signs, for police, and at your speedometer, the less attentive
you will be to traffic conditions. The limits on attention are much
more severe than most people imagine. And it takes only a momentary
lapse, at the wrong time, to cause a serious accident.