TRANSPORTATION AGENCIES EXPERIENCES WITH DECISION-SUPPORT SYSTEMS FORAIRPORT GROUND ACCESS PLANNING

This article reports on a field investigation into the ways that trans portation agencies use quantitative and qualitative information for ma king strategic decisions regarding airport ground access. The study an alyzes the value of this information for planning airport ground acces s improvements at seven major international airport sites. The major f inding of the research is that quantitative modeling for strategic dec ision support is very difficult, costly and time consuming. Modelers a re confident that the models are accurate and reliable but executives generally lack confidence in the results. Transportation officials bel ieve that the information supplied is flawed by a number of defects th at minimize its value for strategic decision makers. The information d efects described in this article provide an analysis of the structural difficulty of using quantitative modeling for transportation problems of strategic importance. To date, qualitative information is not freq uently used, but some transportation agencies are considering its appl ication to designing transportation services. Although this study is l imited to airport ground access, the authors feel that this evidence, in conjunction with the evidence from other studies in the transportat ion area, dictates a need for wariness in the development of decision support systems for transportation planners. Developers of decision su pport systems for transportation planners must be aware of modeling co sts and defects and consider how to improve the timeliness, relevance and credibility of information quantitative models provide transportat ion executives. Fundamentally it is important to recognize that decisi on makers tend, either singularly or in concert with other individuals or groups, to be the champions of a long-term vision for the communit y. When modeling produces inconsistent or wide ranging results that co ntradict their position, decision makers may not only discard modeling activities, but lose confidence in the models altogether. As a conseq uence, transportation planners are faced with the challenge of how to improve quantitative modeling. The most reliable and effective means f or improvement is incorporation of qualitative techniques which provid e greater understanding of customer perceptions and human behavior.