We live in a world at the point of significant change: Around half of us recognise that we need to travel less, just at the same time as the other half want to travel more. There is little doubt that, without a major technology shift, those in the developed world who are used to high levels of personal mobility cannot all continue to behave in the same way as they have done in the past. While in the fast-growing emerging economies, with burgeoning middle classes, many see the desire for individual car ownership as a credible and realistic aim. We are at a tipping point between the two seemingly opposing drivers of sustainability and aspiration. Our primary challenge is in balancing these two.