where TVADD is the total value added in a particular year in HKD, and VADDmj is the value added in a particular year due to the transportation mode mj. Eq. (3) shows that a lower value of ENVEFF
(or ENVEFFmj ) represents the transport mode to be more environmentally
friendly.
In addition to the environmental performance, the economic
performance in terms of productivity per tonne-km of cargo due to
the logistics services needs to be determined and is given in Eq. (4).