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Pages 59-70

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From page 59...
... 59 The NCRRP 03-02 amplified work plan called for the creation of two discrete choice models for the analysis of intercity travel. First, the data from the stated choice exercises were used to create a mode share model based on transportation level-of-service factors such as times, costs, and other traditional inputs such as demographics and party size.
From page 60...
... 60 Intercity Passenger Rail in the Context of Dynamic Travel Markets 5.1 A Mode Choice Model with No Attitudes or Preferences 5.1.1 Model Design Stated preference (SP) and stated choice exercises incorporate a type of tradeoff analysis tool also used in choice-based conjoint analyses, but the latter method is more commonly used in market research, whereas the former is more common in the transportation literature.
From page 61...
... Merging Economic Modeling Theory with Analysis of Attitudes and Preferences 61 Figure 43. Example of a travel scenario from the stated choice exercise presented to a respondent from Washington, DC.
From page 62...
... 62 Intercity Passenger Rail in the Context of Dynamic Travel Markets sophisticated models, including the ICLV models that are summarized in Section 5.2 and presented in full detail in NCRRP Web-Only Document 2, Technical Appendix: ICLV and Hybrid Model Development. 5.2 Integrated Choice and Latent Variable Modeling 5.2.1 Background: Activities in the Development of the ICLV Model As described previously, the research team undertook an ambitious survey effort designed to estimate ICLV models (also known as hybrid models)
From page 63...
... Merging Economic Modeling Theory with Analysis of Attitudes and Preferences 63 The gap between discrete choice models including only level-of-service variables and behavioral theory has encouraged different developments that attempt to enrich behavioral realism by explicitly modeling one or more components of the respondents' decision-making process (e.g., accounting for attitudes and perceptions)
From page 64...
... 64 Intercity Passenger Rail in the Context of Dynamic Travel Markets as the per-person cost; for car, the research team recognized that the driver often pays a larger share and thus multiplied the total cost by a factor to deal with party size. For car, access time and egress time were set to zero.
From page 65...
... Merging Economic Modeling Theory with Analysis of Attitudes and Preferences 65 Each of these latent attitudes is defined to have a deterministic and a random component, with latent attitude l for person n being: , ,zl n l n l nα = γ + ξ where the estimates of gl capture the impact of a range of sociodemographic characteristics of person n (zn) on the latent attitude, and where xl is a standard Normal variate (mean of 0, standard deviation of 1)
From page 66...
... 66 Intercity Passenger Rail in the Context of Dynamic Travel Markets • The mode-specific constants, which include a deterministic component as well as a random part • An impact on the modal constants by the latent attitudes, which again include a deterministic and random component. Other Elements of Model Composition Two observations are offered to help understand the composition of the model: • Firstly, the sociodemographic terms included in the modal constants explained above relate to person as well as trip characteristics, while those sociodemographic terms mentioned earlier for the latent attitudes related only to person characteristics.
From page 67...
... Merging Economic Modeling Theory with Analysis of Attitudes and Preferences 67 high mean, but is not surprising due to the fact these are intercity travelers in two major US corridors making discretionary or business trips) and the mean and standard deviation of the distribution resulting from the ratio between the negative log-uniform distributions for the time and cost coefficients are reported.
From page 68...
... 68 Intercity Passenger Rail in the Context of Dynamic Travel Markets Numerous shifts in the modal constants are also observed, as follows: • Age has impacts for bus and air, where – On vacation trips, the likelihood of traveling by bus is higher for respondents under 35 and – The likelihood of traveling by air decreases for VFR purposes in the two highest age groups but increases in the highest age group for other purposes. • Having more vehicles than licenses in a household increases the probability of traveling by car for work trips.
From page 69...
... Merging Economic Modeling Theory with Analysis of Attitudes and Preferences 69 or air (for all purposes other than work) , while, for work trips, they are more likely to choose rail.
From page 70...
... 70 Intercity Passenger Rail in the Context of Dynamic Travel Markets e-mail or text message updates about my bus or train trip" and "Being able to freely perform tasks, including using a laptop, tablet, or smartphone is important to me." This thus identifies this latent attitude as a pro-ICT attitude. The demographic parameters show that, for VFR trips, these respondents are more likely to be female, highly educated, or employed and are more likely to be younger (for both VFR and "other" purposes)

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