When I was visiting my family in India, I used to walk around town and wonder how drivers could tell if they were on a one-way street. It was obvious for vehicles trying to enter the street from the wrong end, because there were 'no-entry' signs. But that wasn't enough. Vehicles coming in from the other side needed to be told that they were entering a one-way street too, just in case they suddenly wanted to turn around and go back. In the city I was visiting at the time, Delhi, the transportation department must have wisely decided to save money by relying on people's observational skil…
