It can be dangerous to mix stable systems.

The passenger in the car comes from a social system where red means stop and green means go. For the passenger, all professional taxi drivers (and drivers) follow that system. Because everyone follows the norms of the system, the system is safe.

For the taxi cab driver, red = yield and green = caution. To the driver, all professional taxi drivers follow that system. Because everyone follows the norms of the system, the system is safe.

If the passenger forced the taxi cab driver to follow the more western system, both passenger and drive could be injured.

What I love most about travel is the opportunity to crack cultural codes — now I know to not freak out in a Cairo cab.

HT Tyler Cowen for sharing the X-post.