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From page 302... ... H-1 Integrated Choice and Latent Variable Models A p p e n d i x H Contents H-2 Model Formulation H-10 Summary of Latent Variables H-11 Chicago Models H-26 Charlotte Models H-38 Summary of Model Results Underlying attitudes and perceptions are potentially a key driver in explaining respondents' choices in real-world scenarios as well as in hypothetical settings. The survey work captured respondents' answers to a number of attitudinal questions. Read the entire page →
From page 303... ... H-2 Characteristics of premium Transit Services that Affect Choice of Mode for forecasting purposes. In the ICLV model, the estimation produces parameters for the distribution of the latent variables, and these can then be directly used in model application. Read the entire page →
From page 304... ... integrated Choice and Latent Variable Models H-3 one of the S latent variables is used for a given indicator k, where, typically, a given latent variable is used for more than one indicator. Assume that latent variable ns is used to explain the value for indicator k. Read the entire page →
From page 305... ... H-4 Characteristics of premium Transit Services that Affect Choice of Mode Independently of the specific functional form used for LInk, it is thus established that this probability is a function of n, rewritten as Lnk( n) , and the probability of the observed values for the entire set of K indicators is given as follows: where possible additional layers of integration need to be added if random heterogeneity not linked to the latent variables is to be introduced in the model. Read the entire page →
From page 306... ... integrated Choice and Latent Variable Models H-5 2: Willingness to Walk This latent variable is used to explain the value of a single indicator, namely the stated willingness to walk. This is a continuous variable, and a continuous specification was thus used, where, after subtracting the sample mean from the indicator for each person, only two parameters are estimated, namely a parameter capturing the impact of the latent variable on the indicator, and a parameter capturing the standard deviation of the indicator. Read the entire page →
From page 307... ... H-6 Characteristics of premium Transit Services that Affect Choice of Mode - the number of vehicles in the respondent's household; - the log of household income; - whether a respondent has reduced mobility; and - whether a respondent's household has more drivers than vehicles. In the choice model, this latent variable was interacted with the constants for bus and train. Read the entire page →
From page 308... ... integrated Choice and Latent Variable Models H-7 - respondent's agreement with the statement, If it would save time, I would change my form of travel. Each of these has five levels, and an ordered logit specification was used, with four thresholds each. Read the entire page →
From page 309... ... H-8 Characteristics of premium Transit Services that Affect Choice of Mode Each of these has five levels, and an ordered logit specification was used, with four thresholds each. Three sociodemographic characteristic were used in the deterministic component of this latent variable, namely: - whether a respondent is female; - the number of vehicles a respondent's household owns; and - whether children are present in the household. Read the entire page →
From page 310... ... integrated Choice and Latent Variable Models H-9 Model Exploration for Awareness and Consideration An additional model investigation was carried out as part of this analysis, making use of latent variable models, in which were jointly modeled not just the choices and responses to attitudinal questions, as in the above, but also the responses to the awareness and consideration questions. To this extent, the likelihood of the observed value for awareness for bus for respondent n was modeled as: making it a function of the latent uninformedness attitude ( 1) Read the entire page →
From page 311... ... H-10 Characteristics of premium Transit Services that Affect Choice of Mode Very preliminary work was also conducted to explore the potential for modeling choice set generation in the present context. Specifically, the latent level of consideration of any unchosen RP alternative, say bus, could be written as: noting that the latent consideration is itself a function of other latent variables from the overall model (and a constant) Read the entire page →
From page 312... ... integrated Choice and Latent Variable Models H-11 TABLE H-1. Description of latent variables. Read the entire page →
From page 313... ... H-12 Characteristics of premium Transit Services that Affect Choice of Mode between the RP and SP scales are substantially larger than was the case in the simple MNL models. Additionally, both segments show higher scale for SP than for RP, where this was only the case for the commuter segment in the simple MNL model. Read the entire page →
From page 314... ... integrated Choice and Latent Variable Models H-13 A number of changes to significance levels also are noted, with fluctuations for most parameters, but where few of these involve a change from significance to non-significance (or vice versa) , with some exceptions, as follows: The fixed mean parameters for both alternative specific constants are no longer statistically significant, most likely as these effects are now captured in the variation in these constants in interaction with the latent variables. Read the entire page →
From page 315... ... TABLE H-3. Base utility parameters for ICLV model in Chicago. Read the entire page →
From page 316... ... TABLE H-3. (Continued) Read the entire page →
From page 317... ... H-16 Characteristics of premium Transit Services that Affect Choice of Mode Value of Time Measures As a next step, the estimates from the two models are used to compute value of time measures for the two segments and the three different modes of travel (TABLE H-4) Read the entire page →
From page 318... ... integrated Choice and Latent Variable Models H-17 TABLE H-5. Equivalent IVTT (in minutes) Read the entire page →
From page 319... ... H-18 Characteristics of premium Transit Services that Affect Choice of Mode and non-commuters. However, no impact of this latent variable is observed for non-commuters for either mode, or for train in the commuter segment. Read the entire page →
From page 320... ... integrated Choice and Latent Variable Models H-19 TABLE H-7. 2: Willingness to walk. Read the entire page →
From page 321... ... H-20 Characteristics of premium Transit Services that Affect Choice of Mode TABLE H-8. 3: Pro-transit attitude. Read the entire page →
From page 322... ... integrated Choice and Latent Variable Models H-21 The fourth latent variable (pro-car attitude) is interacted with six indicators in an ordered logit specification, meaning that increases in the indicators (i.e., stronger agreement with the attitudinal statements) Read the entire page →
From page 323... ... H-22 Characteristics of premium Transit Services that Affect Choice of Mode TABLE H-9. 4:Pro-car attitude. Read the entire page →
From page 324... ... integrated Choice and Latent Variable Models H-23 TABLE H-10. 5:Productivity attitude. Read the entire page →
From page 325... ... H-24 Characteristics of premium Transit Services that Affect Choice of Mode TABLE H-12. 7: Privacy and comfort attitude. Read the entire page →
From page 326... ... integrated Choice and Latent Variable Models H-25 majority of respondents who indicated that they were aware of the mode also indicating that they had considered it. Read the entire page →
From page 327... ... H-26 Characteristics of premium Transit Services that Affect Choice of Mode abandoning this exploratory research -- for example, in the Charlotte non-commuter segment, every respondent who had stated to be aware of train had also stated to have considered it. Furthermore, it should be remembered that the awareness component could only be included when the mode was actually available, where this for example applies to only 38% of Chicago commuters for bus, and 41% for train, leading to small sample sizes. Read the entire page →
From page 328... ... integrated Choice and Latent Variable Models H-27 other distinction arises in the deterministic treatment of the stated level of transit information and the stated willingness to walk in the earlier models. A closer study of the ICLV results for the non-commuter segment, which is to follow, shows a lack of impact of the latent variables in the choice model part of the overall structure. Read the entire page →
From page 329... ... H-28 Characteristics of premium Transit Services that Affect Choice of Mode questions. This thus leads to only 465 individual contributions to the log-likelihood function. Read the entire page →
From page 330... ... TABLE H-15. Base utility parameters for ICLV model in Charlotte. Read the entire page →
From page 331... ... Commuters Non-commuters Auto Bus Train Auto Bus Train Individual Demographics Full-time student 0.1531 1.72 0.1531 1.72 Full-time employed -0.7927 -0.39 0.1918 1.79 Homemaker -0.3588 -2.00 Retired Female -0.7057 -0.47 -0.0289 -0.53 Longtime resident (5+yrs) -0.0928 -1.13 -0.1057 -1.50 Has mobility problem 0.7207 1.74 Age less than 35 years -0.0926 -1.52 -0.0926 -1.52 Age between 35 and 55 years Age more than 55 years -2.3307 -0.65 0.0168 0.28 0.0168 0.28 Household Demographics Number of vehicles in household Family income(in income) Read the entire page →
From page 332... ... Integrated Choice and Latent Variable Models H-31 TABLE H-16. Value of time ($/hour) Read the entire page →
From page 333... ... H-32 Characteristics of premium Transit Services that Affect Choice of Mode Commute Non-Commute Explanatory Variables Auto Bus Train Auto Bus Train Individual Demographics Full-time student - (14.13) Read the entire page →
From page 334... ... integrated Choice and Latent Variable Models H-33 TABLE H-18. 1: Level of lack of transit information -- Charlotte. Read the entire page →
From page 335... ... H-34 Characteristics of premium Transit Services that Affect Choice of Mode Turning to the pro-transit latent attitude (TABLE H-20) , a more positive attitude by fulltime students is noted in the commuter segment, with negative impacts on the latent attitude (i.e., less pro-transit) Read the entire page →
From page 336... ... integrated Choice and Latent Variable Models H-35 TABLE H-20. 3: Pro-transit attitude -- Charlotte. Read the entire page →
From page 337... ... H-36 Characteristics of premium Transit Services that Affect Choice of Mode TABLE H-21. 4: Pro-car attitude -- Charlotte. Read the entire page →
From page 338... ... integrated Choice and Latent Variable Models H-37 TABLE H-22. 5: Productivity attitude -- Charlotte. Read the entire page →
From page 339... ... H-38 Characteristics of premium Transit Services that Affect Choice of Mode TABLE H-24. 7: Privacy and comfort attitude -- Charlotte. Read the entire page →
From page 340... ... integrated Choice and Latent Variable Models H-39 The key findings relate to the role of the latent variables in the models, as shown in TABLE H-25. In this brief summary, we present the results in simplified table form, where +++/ -- represent positive/negative effects that are significant at the 99% level of confidence, using ++/ -- for the 95% level, and +/- for the 90% level. Read the entire page →
From page 341... ... H-40 Characteristics of premium Transit Services that Affect Choice of Mode TABLE H-25. Summary of latent variable findings. Read the entire page →
From page 342... ... integrated Choice and Latent Variable Models H-41 TABLE H-25. (Continued) Read the entire page →
From page 343... ... H-42 Characteristics of premium Transit Services that Affect Choice of Mode TABLE H-25. (Continued) Read the entire page →

From page 302...

... H-1 Integrated Choice and Latent Variable Models A p p e n d i x H Contents H-2 Model Formulation H-10 Summary of Latent Variables H-11 Chicago Models H-26 Charlotte Models H-38 Summary of Model Results Underlying attitudes and perceptions are potentially a key driver in explaining respondents' choices in real-world scenarios as well as in hypothetical settings. The survey work captured respondents' answers to a number of attitudinal questions.