Analysing Demand for Suburban Trips: A Mixed RP/SP Model with Latent Variables and Interaction Effects

We analyse mode choice behaviour for suburban trips in the Grand Canary island using mixed revealed preference (RP)/stated preference (SP) information. The SP choice experiment allowed for interactions among the main policy variables: travel cost, travel time and frequency, and also to test the influence of latent variables such as comfort. It also led to discuss additional requirements on the size and sign of the estimated model parameters, to assess model quality when interactions are present. The RP survey produced data on actual trip behaviour and was used to adapt the SP choice experiment. During the specification searches we detected the presence of income effect and were able to derive willingness-to-pay measures, such as the subjective value of time, which varied among individuals. We also studied the systematic heterogeneity in individual tastes through the specification of models allowing for interactions between level-of-service and socio-economic variables. We concluded examining the sensitivity of travellers’ behaviour to various policy scenarios. In particular, it seems that contrary to political opinion, in a crowded island policies penalising the use of the private car seem to have a far greater impact in terms of bus patronage than policies implying direct improvements to the public transport service.     

Choice of parking: Stated preference approach

Over recent years, parking policy has become a key element of transport policy in many countries. Parking policy measures can affect many different dimensions of travel behaviour but are likely to be most significant in terms of travellers' choice of parking type and location. This dimension of travel choice has, to date, received comparatively little attention, yet is of vital importance if we are to properly understand and predict the effects of parking policy measures.This paper presents two studies addressing this issue carried out in the United Kingdom and Germany. Both studies used a stated preference approach in order to collect disaggregate data on travellers responses to changes in parking attributes and used these data to build simple logit models of parking type choice. The studies were designed in order to allow comparable choice models to be estimated from the two datasets. The results obtained strongly indicate the need to separately identify the costs associated with different components of the parking activity (e.g., general in-vehicle time, parking search time, egress time) and also point to the existence of significant differences in the relative valuation of these components across different journey purposes. Where possible, the results of the choice modelling exercises are also compared with existing revealed and stated preference results and are found to be generally in line with prior expectations.     

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城市公共交通乘客出行成本的量化研究,对于科学合理地评价公共交通系统的社会效益意义重大,而出行时间价值是进行乘客出行成本估计的一个重要环节. 本文以北京市市区居民SP调查数据为依托,通过分析公共交通出行时间价值的影响因素,选取Logit模型为基础模型,引入“出行者收入”作为模型新增变量,并针对工作商务、社会娱乐两种出行目的在不同换乘情况下出行时间价值模型进行参数标定,建立了基于SP调查数据的改进型时间价值求解模型,并计算得到北京市公共交通出行者在不同出行目的和有无换乘情况下的换乘时间价值、候车时间价值以及运行时间价值. 研究发现,工作商务出行目的出行时间价值普遍高于社会娱乐的出行时间价值,出行者在不同出行目的和有无换乘情况下的候车时间价值,大于换乘时间价值以及运行时间价值,并且有换乘情况下的候车时间价值大于无换乘情况下的候车时间价值.     

道路交通统计生命价值测算模型及其验证

基于参数服从SB分布的混合Logit 模型进行道路交通统计生命价值的测算研究. 首先，结合意愿选择法和正交实验法设计出行路径选择调查问卷；然后，基于死亡风险系数服从对数正态分布和SB分布的混合Logit 模型，构建统计生命价值测算模型；接着以大连市私家车出行者为调查对象获得调查数据，并利用Monte Carlo 仿真方法进行模型参数标定；最后，对模型进行比较分析，并获得统计生命价值的测算值. 研究结果表明：死亡风险参数服从限制域为(0.0, 0.5)SB分布的混合Logit 模型，精确性更高且更合理；道路交通统计生命价值测算值为 105.76万元，这一结果可以作为道路交通安全项目经济评价的参考数据.     

A practical assessment of stated preferences methods

Stated preferences data in the form of rankings, ratings and choices were collected in Santiago and discrete choice models estimated with them. The models were compared in terms of accuracy v/s the cost of obtaining the information and models. All methods produced reasonable but different models and fairly close subjective values of time. In terms of production costs the ranking method was a clear looser although the experimental design was slightly biased against it. Finally, the use of computerised interviews is highly recommended particularly for dealing with low income people.     

A stated preference examination of time of travel choice for a recreational trip

A stated preference experiment was performed in Calgary in Canada to examine how people are influenced in the selection of a departure time for a hypothetical trip to see a movie. A total of 635 complete observations were obtained. In each observation the respondent was presented with a set of possible departure time scenarios and asked to indicate the order of preference for these scenarios. Each scenario was described by specifying the automobile travel time, the expected arrival time relative to the movie start time, the parking cost, the probability of being at least ten minutes late for the movie and the length of time the movie had been running. This forced the respondent to trade off between conditions regarding these attributes. Age, gender and frequency of movie attendance were also recorded. The observations thus obtained were used to estimate the parameter values for a range of alternative utility functions in logit models representing this choice behaviour. The results indicate that all of the attributes included have significant effects on departure time choice in the situation being considered. They also indicate that travellers are prepared to arrive roughly two minutes early for each minute of travel time saved; that the money value of driving time for trips to recreational activities is about half that for trips to work; that one additional percent in the probability of arriving late is equivalent to roughly 0.20 Canadian dollars or 1.93 minutes drive time; and that there is a preference for a non-zero expected early arrival time regardless of the associated probability of arriving late. Some of these results are novel and others are consistent with findings for work trips in work done by others, which is seen to add credence to the approach being used here.     

Improved Urban Inhabitant Travel Demand Model and Its Application

Transport planners often need to forecast the influence of the transport policies on travel demand, e.g., construction of a new transport alternative, changing public transit fares, or imposing road pricing schemes. Stated preference (SP) surveys are frequently adopted by transport planners for the analysis of the impact of transport policies on travel demand. However, evidence suggests that preferences derived from SP surveys are contingent on context, which indicates that trip makers may show asymmetric preferences for different levels of services. The objective of this article is to propose an alternative conceptual framework for travel demand analysis. It is expected that travel behavior may be heterogeneous across trip makers; response (or parameter of) to the level of service is defined as a function of the attributes of the trip makers. It is also aimed to propose some urban transportation policies based on a new type of discrete choice model. In an empirical demonstration, the panel data obtained from commuters in Lanzhou, China, are used, and support is obtained for several predictions on why behavioral intentions are, or are not, implemented.     

A study of carpooling behaviour using a stated preference web survey in selected cities of India

This paper analyses how people perceive the idea of carpooling and evaluate preferences while making a decision to join a carpool. Analysing data from a web-based stated preference survey in India reveals that cognitive attitudes play a significant role in evaluating the perceived advantages and disadvantages of carpooling whereas intentions to carpool are associated with perceived negative evaluations. A factor analysis identifies two latent attitudinal factors: a ‘time–convenience’ factor that discourages carpooling and a ‘private–public cost’ factor that encourages carpooling. The study analyses the influential attributes – extra travel time, walking time to reach meeting point, waiting time at pickup point and cost savings – as explanatory variables for the utility of carpooling. Cost savings prove to be the most significant attribute when combined with other attributes, followed by extra travel time. The study provides the implications to policy-makers of designing promotional tools to improve the propensity of carpooling among single occupant vehicle drivers.