Formal problems of transportation impact research

Abstract

FORMAL PROBLEMS IMPACT OF TRANSPORTATION RESEARCH Christian Werner University of California, I. Irvine Introduction The subject of this paper is the e m p i r i c a l , inductive approach as a method of determining quantitatively the influence which a transportation s y s - tem e x e r c i s e s on its environment. P r o b l e m s r e f e r r i n g s t r i c t l y to methods of st at i s t i cal analysis have been omitted; they are sufficiently c o v e r e d in t ex t - books on this subject. F u r t h e r m o r e , a specific form of impact, namely, the feedback on the t r a n s p o r t a t i o n s y s t e m , has not been dealt with. Since some of the m o r e important r e s e a r c h p r o b l e m s have not been t r e a t e d p r o p e r l y or not at all in the impact l i t e r a t u r e , this paper contains t r i v i a l statements in places. Its r e s u l t s are e s s e n t i a l l y crude and p r e l i m i n a r y , but they do provide some f o r m a l organization and suggest improvements of the s c a r c e body of inductive impact r e s e a r c h methods so far available. Transportation impact r e s e a r c h is commonly considered as the study of the effect which transportation phenomena e x e r c i s e on other things. Hence, the raw m a t e r i a l of such a study consists of the description of transportation features and p r o c e s s e s as well as the environment with which they interact. The final goal is the description and explanation of these interactions. Both transportation and environmental phenomena can best be described with the concept of the property space to which the dimensions of space and time are added. Thus, the input information of a transportation impact study can be organized according to the dimensions of space, time and the various p r o p e r - ties (variables). The second step will then be concerned with the determination of interrelationships between transportation and environmental v a r i a b l e s in space and time. If, in addition, the impact study is to develop predictive power, the final section has to be concerned with the extrapolation of the variables and their interrelationships over the dimensions of time, space, and property scales. II. The Variables Since r e a l world phenomena usually display a large degree of complexity, the t e r m variable should be used only for their one-dimensional p r o p e r t i e s . T h e r e is no t h e o r e t i c a l way to d e t e r m i n e always in advance, which t r a n s p o r t a - tion v a r i a b l e s e x e r c i s e influence on their environment, and which en v i r o n m en - tal v a r i a b l e s will be affected. The selection of v a r i a b l e s will t h e r e f o r e be 1The support of the Department of Transportation, F e d e r a l Railroad Administration (Contract Nr. 7-35524), Washington, D. C., is gratefully acknowledged.