Many city buses have signs to the effect of “Don’t disturb the driver.” Kenya took the opposite approach. They posted signs in minivans encouraging passengers to “heckle and chide” the drivers when they witnessed unsafe driving. It worked. Accidents went down, although as the authors note, there could be several explanations in addition to voluble backseat drivers.
Turn-by-turntables: How drivers got from point A to point B in the early 1900s
Long before GPS, drivers still wanted tech that could simplify the navigation process.