How to make sustainable transportation a reality

Sustainable development is an extremely prevalent concept. It is part of almost all political programmes, companies agree to this goal, and a wealth of scientific studies deal with it. Why then, in spite of all this, is it so difficult to make progress towards this goal?
One reason lies in the difficulty in quantifying the goal of sustainable development. It is a process characterised by constant learning, searching and designing, and therefore by a certain degree of openness and uncertainty.
So how can one define measures toward a goal that is impossible to quantify? The aim of this book is to present ways for the transport sector to resolve the contradiction between the process nature of sustainable development on the one hand, and the demand for a precisely measurable goal on the other. This is done using a development corridor. Progress towards sustainable transportation development can be guaranteed by remaining within the corridor's boundaries. It represents a space for "constant learning, searching and designing".