Work related travel

Work related travel probably has a huge carbon footrprint, but there seems to be very little discussion of this topic from a kind of overview perspective. It particularly affects global cities and the areas and communities in, around and between them.

For cities or other areas is it possible to find out:
 * What is the carbon footprint of work - related air travel?
 * What is the carbon footprint of work - related car travel?

For example it would be interesting to see what percentages of London and South East England's carbon footprints are a result of patterns.

Related topics

 * Reduced dependence on cars
 * Reduced dependence on flying