ANALYSIS OF USER PREFERENCES FOR SYSTEM CHARACTERISTICS TO CAUSE A MODAL SHIFT

THIS STUDY IS AN INVESTIGATION OF THE USE OF SUBJECTIVE PREFERENCES TO COMPLEMENT BEHAVIORAL OBSERVATIONS AS A MEANS OF DETERMINING THE PROPENSITY, OR TENDENCY, OF AN INDIVIDUAL AUTOMOBILE DRIVER TO SHIFT TO A NEW MODE. A SO-CALLED PROPENSITY MODEL OF THE DISCRIMINATION-CLASSIFICATION TYPE IS FORMULATED FROM INDIVIDUAL PREFERENCES FOR THE PERFORMANCE CHARACTERISTICS REQUIRED TO ENCOURAGE A SHIFT TO A MULTIMODAL PARK-AND-RIDE TYPE OF TRANSPORTATION SYSTEM OR, CONVERSELY, A CHANGE IN DOWNTOWN PARKING COST TO EFFECT A SHIFT TO BUS TRANSIT. THE PROPENSITY MODEL INDICATES THAT A SUBSTANTIAL SHIFT COULD BE BROUGHT ABOUT BY RELATIVELY SMALL DECREASES IN OVERALL TRAVEL TIME, PROVIDED THAT WALK TIMES IN PARKING TERMINALS ARE ABOUT 2 MIN OR LESS AND TRANSIT LINE-HAUL FREQUENCY IS 4 1/2 MIN OR LESS. PARKING CHARGES WERE FOUND TO BE AN EFFECTIVE INSTRUMENT TO CREATE A SHIFT TO BUS TRANSIT. THE VALIDITY OF THE PREFERENCE-BASED MODEL IS TESTED BY ANALYZING THE DEGREE TO WHICH STATED PREFERENCES ARE INDEPENDENT OF EXISTING SERVICE LEVELS. THE TEST SHOWS THAT RESPONDENT PREFERENCES FOR TRAVEL TIME AND PARKING COSTS WERE NOT RADICALLY DIFFERENT FROM THOSE EXISTING, BUT THAT WALK TIMES AND TRANSIT FREQUENCY FOR A NEW MODE MUST BE RADICALLY DIFFERENT. IT IS CONCLUDED THAT SUBJECTIVE PREFERENCES ARE USEFUL TO STUDY TRAVEL MODE DIVERSION, BUT THAT BETTER SUBJECTIVE SURVEYS AND MEANS OF CONTROLLING AND MONITORING CHANGES IN MODAL SPLIT WITH CHANGES IN POLICY-RELATED VARIABLES ARE NEEDED.