Dynamic travel demand models incorporating un observed heterogeneity and First-order serial correlation 【Article】

Very little work using repeated cross-sectional data has been undertaken in transport research. This is especiallytrue for travel data gathered at multiple points in time, especially data that is gathered every 5-10 years such asUrban Area Travel Survey Data and Road Traffic Census Data in Japan. Accordingly, travel demand modelingbased on these types of data is not yet fully developed. This paper deals with methods for developing models whichinclude time series factors for predicting travel demand using three time-points travel data gathered in Hiroshima.As a result, it was shown that model parameters based on cross-sectional data were not stable over time by usingCovariance Analysis or T-Statistic. The existence of first-order serial correlation in residuals was confirmed byusing Generalized Durbin-Watson Statistics, while unobserved heterogeneity was checked by using Breusch-PaganStatistics. Fixed-effects models using these two factors were developed and it was shown that their predicting accu-racy was improved in comparison to traditional cross-sectional models

Mode Choice Models Based on Stated Preference Panel Data Including Refreshed Samples

This paper deals with mode choice models based on panel data including refreshed samples at each wave. Four stated preference data sets concerning mode choice were used for this study, which were collected during 1987 to 93 in Hiroshima. It was first statistically confirmed that sample distribution with respect to socio-demographic characteristics for these data sets, represents the distribution in the population by examining the share of male respondents as a case study. Generalized Durbin-Watson test was used to check the null hypothesis on temporal independence for aggregate mode choice models of logit type. This test indicated that serial correlation for disturbance terms of the models constructed at each time point is significantly large. Therefore, models introducing the serial correlation were developed using Seemingly Unrelated Regression procedure. This could improved the statistical significance of estimated parameters, even though they did not provide higher correlation coefficients

The Effect of Sociodemographic Characteristics on Individual Daily Travel Behaviour

This study examiens the hypothesis that daily travel-activity behaviour is influenced by the household role, life cycle and other attributes of individuals and households using conventional origin-destination data sets. Daily travel-activity behaviour is described by ten categorical factors including trip rate, number of trip chain, number of sojourn, daily travel time, trip patterns and five different activity hours. The explanatory variables used in this study are life cycle, age, role, household size and car ownership. A specific representation in time and space of travel-activity relationship and a statistical analysis based on the log-linear model are employed to test the hypothetical relationship. The former qualitative analysis demonstrates that life cycle is a key determinant in deciding wife's travel behaviour, while husband and children are not influenced by life cycle in their daily travel behaviour. The latter statistical analysis confirms above empirical evidence and derives a further fact that daily travel-activity behaviour of wife in the household is significantly influenced by her role and age as well. This result indicates that interdependences of all household members in their daily travel-activity behaviour reported from European and American countries cannot be seen in Japan

The Characteristics of Mode Choice Models based on Stated Preference Data : A Study of the New Transit System in Hiroshima

Ordered stated preference data including the degree of individuals' preference were interviewed and some characteristics of mode choice models based on those data were investigated to estimate the mode choice behaviour after the introduction of the New Transit System in Hiroshima. First, we compared the reliability of models based on the stated preference data (SP models) with the conventional models on the revealed preference data (RP models). Although SP models were less accurate than RP models to estimate their actual behavior, the difference of both models were not statistically significant. Secondly, in an attempt to examine the bias caused by the fatigue and inertia for three times repetitive questions, the MNL models developed by data sets from the first to the last question were successively specified. This led to a fact that the repetitive answered bias was not significant, which means that the repetitive questions were important to save our efforts to collect the data associated with stated preference. Finally, we introduced the ordered logit models which were able to incorporate the informations related to all ordered data sets. The signs of parameters of ordered logit models were logically adequate and the model efficiency of these models was shown as good as that of conventional MNL models

Effectiveness of Stated Preference Survey Using Portable Computers

The significance of stated preference data obtained using portable computers was empirically supported by comparing this with the data from a conventional paper-based questionnaire survey. The internal validity of mode choice models based on Mulitinomial and Rank logit types was tested for these two different data sets which were obtained in Hiroshima, 1988 and 1989. As a result, the computerized interview data represented a higher level of fit in model specification than the manually completed data, indicating the effectiveness of the former survey method

Dynamic Analysis of Stated Preference for Travel Modes Using Panel Data <研究ノート>

Dynamic analysis of stated preference, for the New Transit System of Light Rail type which was opened in 1994 in Hiroshima, was carried out using the panel data collected for work and school trips at two points in time; 1987 and 90. It was first empirically demonstrated that the stated preference for the NTS is greatly affected by actual travel modes consisting of car and bus, and that the temporal changes of stated preference which were caused by the change of actual travel mode, do not support the Markovian assumptions which indicate the individual's responses to a change of travel environment over the three years. The importance of state dependence was also demonstrated by building dynamic SP mode choice models of Multinomial Logit type

CORRECTING ATTRITION BIAS IN STATED PREFERENCE MODE CHOICE MODELS <研究ノート>

This paper aims at examining the extent of attrition biases specifically included in Stated Preference data and also demonstrates the effectiveness of a correcting method which exclude them in model building. SP panel data for the New Light Rail Transit System in Hiroshima, measured at two different points in time, was used for this purpose. As a result, the effect of attrition bias on mode choice model parameters based on SP data was empirically clarified. Attrition models which determine whether the respondents of the first wave participate in the second survey or not were developed using first wave data. In addition, a mode choice model was constructed based on the stayers (i.e. participants in the first wave who participated in the second wave) at the second wave. The attrition bias of this model was corrected by sequential steps on the assumption that the error in the mode choice model correlates with that of the attrition model. It was found that this type of correcting could effectively cancel out the biased share of each travel mode

Evaluation of community roads by surrounding residents in Hiroshima

本研究は1983年以降広島市で建設された5個所のコミュニティ道路の事後評価をアンケート調査を通じて行い、今後の拡充のための必要な情報を入手しようとするものである。その結果、既存のコミュニティ道路の評価はそれぞれの地区で異なるが、全体として周辺住民に好意的に受け入れられていることがわかった。しかし、新しく自分の家の周辺にコミュニティ道路を設けることに対しては、既存のコミュニティ道路ほど賛同が得られないことがわかった。その理由はそれぞれの地区の事情によるものと考えられる。この度新しく建設されたコミュニティ道路に隣接する小学校の生徒に対しても同様なアンケート調査を行うと、小学生も大人と同様にコミュニティ道路を高く評価していることがわかった。この道路の事前事後の車の速度を比較すると、速度低減の効果も大きいことも実証された。This paper aims to evaluate community roads which have been completed since 1983 in Hiroshima and to obtain necessary information for the purpose of developing more community roads. As a result, all of them are favored by the majority of surrounding residents even though the extent of evaluation is different by each road, but further development of the roads in front of their houses is less favored than that of existing roads. The reason seems to be depending on the special situation of each residential area. We can find similar evaluations for the road by school children in an elementary school adjoining their new community road who were specially participated in our survey. It is also confirmed that community road is effective in reducing traffic speed based on a pre and post traffic survey