David Levinson 1 Life-Cycle, Money, Space, and the Allocation of Time by David Levinson, University of California, Berkeley Levinson, David (1999) Title: Space, Money, Life-cycle, and the Allocation of Time. Transportation 26: Space, Money, Life-cycle, and the Allocation of Time
David Levinson 2 Outline Introduction Data Travel Duration Correlations Activity Duration Choice Model Conclusions
David Levinson 3 Introduction Travel and Activity are Two Sides of the Same Coin Time in Travel = f (Time at Activity) Time at Activity = f (Life-Cycle, Money, Space, Temporal Factors, Constraints) Activities Considered (Home, Work, Shop, Other) Daily Activity Budget (24 hrs)
David Levinson 4 Data 1990/91 Nationwide Personal Transportation Survey Survey Inverted to Get Activity Diary Households, individuals, Trips Individuals whose total activities did not add to 1440 minutes, excluded This study looks only at adults (18-65)
David Levinson 5 Travel Duration Travel Duration = f( Activity Duration & Frequency) TDi = ß0 + ß1 * ADi + ß2 * AFi Transport Planning Models Only Consider Activity Frequency, not Duration ADi positive & significant in 6 of 9 activity categories, negative & significant for 1 of 9 (home) [ Staying Home is Substitute for Travel ]
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7 Correlations: Activity Complements or Substitutes Non-Travel Activities are Substitutes Travel is Complementary to Like Activity & Travel to Home; Substitutes for Other Activities.
David Levinson 8 Activity Duration Space (density, metro area, region) Money (income, work-status, gender) Life-Cycle (age, gender, household size, # adults, age of oldest child)
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David Levinson 23 LifeCycle & Time at Home
David Levinson 24 LifeCycle & Time at Work
David Levinson 25 LifeCycle & Time at Shop
David Levinson 26 LifeCycle & Time at Other
David Levinson 27 LifeCycle & Time at Travel
David Levinson 28 Choice Model Logit model to predict share of time between 4 activities (incl. travel to act.) for individuals who undertook all four Greatest part of explanatory power is in Activity Specific Constant. 2nd most sig = activity frequency
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David Levinson 30 Conclusions Activity Duration a key factor explaining travel duration Activities are substitutes Travel is complement only to like activity & return trip Activity Duration is fairly constant between groups, with large individual variations which are not easily predicted