TEMPORAL STABILITY OF TRIP GENERATION RELATIONS

Abstract

TRIP GENERATION MODELS BASED ON HOUSEHOLD DATA RATHER THAN ZONAL AGGREGATE DATA ARE EVALUAT4D. IT HAS BEEN SUGGESTED THAT ANALYSIS OF HOUSEHOLD TRAVEL CHARACTERISTICS SHOULD PRECEDE AGGREGATION SO THAT HOME-INTERVIEW DATA CAN BE USED MORE EFFICIENTLY. RELATIONS IDENTIFIED AT THE DECISION LEVEL OF TRAVEL SHOULD HAVE GREATER CAUSAL VALIDITY AND SHOULD BE MORE TEMPORALLY AND SPATIALLY STABLE. THE MAJOR OBJECTIVES OF THIS RESEARCH ARE TO EXAMINE THE FORM OF HOUSEHOLD TRAVEL RELATIONS, TO DETERMINE THE STABILITY OF THESE RELATIONS OVER TIME, AND TO EVALUATE THE ABILITY OF HOUSEHOLD MODELS TO ESTIMATE FUTURE TRAVEL. THE POTENTIALS FOR REDUCED SAMPLE SIZES AND GREATER APPLICABILITY OF DISAGGREGATE MODELS IN DIFFERENT URBAN AREAS ARE ALSO EXAMINED. HOUSEHOLD TRAVEL DATA WERE ABTAINED FROM HOME-INTERVIEW SURVEYS IN 1964 AND 1971. SINGLE-FAMILY HOUSEHOLDS INTERVIEWED IN THE 1971 SURVEY REPRESENTED THE IDENTICAL FAMILIES THAT WERE INTERVIEWED IN 1964. THIS UNIQUE SAMPLING DESIGN PERMITTED THE ANALYSIS OF THE EFFECTS THAT CHANGES IN THE HOUSEHOLDS' SOCIOECENOMIC CHARACTERISTICS DURING THE 7-YEAR PERIOD HAD ON TRIP PRODUCTION. THE RESULTS INDICATED THAT THE HOUSEHOLD MODELS BASED ON THE 1964 DATA COULD SUCCESSFULLY PREDICT HOUSEHOLD TRAVEL REPORTED BY THE SAME HOUSEHOLDS IN 1971. THE HOUSEHOLD MODELS FROM BOTH TIME PERIODS COULD BE EXPANDED TO ADEQUATELY ESTIMATE 1974 REPORTED ZONAL AREA TRAVEL. PARAMETERS OF THE DISAGRREGATE MODELS ALSO APPEAR MORE CONSISTENT AMONG GEOGRAPHICAL AREAS AND COULD BE DEVELOPED WITH CONSIDERABLY FEWER DATA THAN COMPARABLE ZONAL MODELS.