What is responsible for the response lag of a significant change in discretionary time use: the built environment, family and social obligations, temporal constraints, or a psychological delay factor?

The use of Weibull form is appropriate, as it allows for either an increasing or decreasing hazard rate function with respect to time.

For a continuous integration\( \int\nolimits_{- \infty }^{\infty } {g\left( s \right)ds} , \) the value of integration is infinitive when g(s) is constant for \( s \in \left( { - \infty ,\infty } \right). \) Since human’s life is usually less than 100 years, it is reasonable to assume the density function of starting time of home location change is constant when \( s \in \left[ { - 100,100} \right] \) and zero when \( s \in \left( { - \infty , - 100} \right) \cup \left( {100,\infty } \right). \) Please note that here “−100” means 100 years prior to study period.

The trip purposes used in the two surveys were slightly different. For wave 1 to 7, the following trip purposes were recorded: work, shopping, school, visiting, free-time, personal, appointments, and home. Among them, visiting, free-time, and personal were classified as discretionary. For wave 8 to 10, the following trip purposes were recorded: home, commute to work, other work-related travel, commute to school, taking child to/from school, lesson, etc., visiting friends or family, errands/picking up/dropping of others, doctor appointments/other medical-related, delivery, shopping, dining/coffee, etc., recreation/exercise/lessons/personal business, volunteering, going to another travel mode, other appointment or meeting, meet/pick up/drop off carpoolers, linked commute trip to/from work, commute from work, commute from college, commute from school, and other. Among them, visiting friends or family, dining/coffee, etc., recreation/exercise/lessons/personal business, and volunteering are classified as discretionary. The time allocation to discretionary activities and associated trips is calculated as the sum of both recorded days in each wave.

A common observation period does not mean that every subject must first participate in the survey in the same year.

Group 1 individuals are the only group on whom we do not need to strictly impose the 5-year study period. This is because as long as a significant change in the time allocation is observed within 5 years, we can calculate the response lag. For example, a person participates from waves 1 to 3. In wave 2, we observe a home location change and in wave 3 we observe a significant change in time allocation as compared to wave 2. Then, the response lag can be calculated as 1 year, even though the person’s total participation in the survey is less than 5 years.

Discretionary facilities include: indoor recreational opportunities (e.g., bars, movie theaters, libraries, museums), indoor sports opportunities (e.g., bowling, swimming pools, health clubs), outdoor recreational opportunities (e.g., zoo, parks, resorts), outdoor sports opportunities (e.g., golf), and religious related opportunities (e.g., churches, temples).

Kockelman and Zhang used land area.

For wave 1 to 7, mandatory activities include those activities whose trip purposes are work or school; for wave 8 to 10, mandatory activities include those activities whose trip purposes are: commute to work, other work-related travel, commute to school, and commute to college are defined as mandatory activities. For maintenance activities, it includes shopping or appointment for wave 1 to 7 and taking child to/from school, lesson, etc., errands/picking up/dropping off others, doctor appointment/other medical-related, delivery, shopping, other appointment/meeting, and meet/pick up/drop off carpoolers for wave 8 to 10.