From Hyperloop to smart roads, technology is changing the way we travel.
In many ways, the motor vehicle has shaped modern society and the urban areas in which more than half of us live. But as global incomes rise, cars and trucks are choking these cities with deadly pollution and productivity-sapping traffic jams.
Today, transport accounts for a fifth of global energy demand and a quarter of energy-related CO2 emissions. That means transport is a major contributor to air pollution.