World's Worst Traffic Jams
Cairo may well be the only city in the Middle East with a subway, but it also has camels, cows, carts, and 20 million people. “Signals are an effective way to fight traffic congestion, but you have to get people to obey them,” says Michael Manville, professor at the Institute of Transportation Studies at UCLA. Another problem? The lack of rain worsens pollution from the old cars, since the atmosphere is not cleansed by the water vapor.