Recent developments In soclotechnkal factors that Influence the Interaction of air travel demand and telecommunication systems, Including technical Innovations, have renewed Interest In this subject. Airlines have expressed concern that they will lose a significant portion of their future business travel growth to the electronic media. To Improve the scientific basis for developing estimates of replaced travel and associated Impacts such as Infrastructure u. tlllzatlon, a research project was carried out on thls topic. In this paper are presented highlights of findings on the determinants of travel substitution and stimulation phenomena. A systematic Investigation of factors and thel. r Interrelationships Is reported. The factors treated Include socioeconomic variables, communication needs, technical capability and cost or telecommunications and trausportatlon, In tltutlonal and policy variables, human factors, and transportatlon-telecommunlcatlons trade-offs In representative spatial and service contexts. Analyses and compiled behavioral Information lead to a better understanding of travel Impacts. Complexities and uncertainties are highlighted. An attempt ls made to provide Insights into the determinants and their lnterrelatlonshJps that could form an Improved basis for projectlng the effects of rapidly evolving telecommunlcatlons on air travel demand and related factors.

The cost and technology of telecommunication systems are improving rapidly while the air transportation sector is experiencing congestion-related difficulties, at a number of locations, in maintaining a level of service that is attractive to business travelers. It is hardly surprising that there is considerable interesc in iransportation and telecommunications. Air transportacion interests have expressed their concern that teleconferencing, more than any other single factor, will adversely affect the growth of business travel, which is the most lucrative segment of their market. Other interests are also desirous of knowing more about this complex subject. Telecommunications firms, agencies, and institutions would like to gain an insight into the extent of substitution for market estimation purposes. Government agencies would like to know the impacts on transportation carriers, services and facilities, and energy conswnption. In the following sections are presented highlights of the findings of a research study on transportation and telecommunications in which substitution and stimulation were examined (1).