The driving in rural Tanzania is intense. Mountains without guard rails, extended trucks going around the curves, sometimes passing each other at the same time. Sometimes creeping, sometimes breakneck speeds. Our race against the setting sun, beautiful against trees and mountains, has been lost, and so we’re on a nighttime road. Already dangerous, it becomes even more chancy with blind curves made blinder. Sorry mom.

There are always people walking and riding bikes alongside the road, no shoulder or sidewalk, trusting that vehicles will avoid them, sometimes at the last moment. I fear for their safety, and for my own trust in the buses they recently emerged from, careening along, crossing road lines when they exist.

A language of signals becomes more and more apparent as we go along – present during the day, it is more visible at night. Sometimes high beams flicker, sometimes horns are tapped, sometimes a right or left turn signal is left on for what seems like no discernible reason. So we ask.

The high beams flicking to you oncoming are a “slow down, caution,” because of a speed trap or a tight curve or a wrecked truck. One slow pulse of high beam is a “hello, I see you. All is well.” As a following car, turn your high beams on to indicate to the vehicle in front of you that you want to pass. A turn signal to the outside for the car behind is “it’s safe to pass,” to the inside is “caution this side.” We think the outside turn signal is also for oncoming traffic, to help define the outside of the car for oncoming traffic. Horns are used as thanks and heads up.

Of course I wonder how this started, how it spread, why it’s so standard now. I wonder how it spreads. And I love how it has people in touch with each other, even from within their little enclosed world of vehicles.