What do we mean by sustainable transport? How do we know if our region is on a sustainable path? What do we need to measure, and how do we know if we're better or worse off next year? How can we use better knowledge to improve our ability to act to improve transport and reduce emissions? This stream of two sessions will explore some of the key tools of measuring the transport-emissions-sustainability link. We have invited speakers from around the world who are on the leading edge of this black art of measurement, speakers from the U.S., Mexico, India, China, and elsewhere.