Transit service quality analysis using cluster analysis and decision trees: a step forward to personalized marketing in public transportation

A transit service quality study based on cluster analysis was performed to extract detailed customer profiles sharing similar appraisals concerning the service. This approach made it possible to detect specific requirements and needs regarding the quality of service and to personalize the marketing strategy. Data from various customer satisfaction surveys conducted by the Transport Consortium of Granada (Spain) were analyzed to distinguish these groups; a decision tree methodology was used to identify the most important service quality attributes influencing passengers’ overall evaluations. Cluster analysis identified four groups of passengers. Comparisons using decision trees among the overall sample of all users and the different groups of passengers identified by cluster analysis led to the discovery of differences in the key attributes encompassed by perceived quality.     

地铁曲线段不规则磨耗引起的钢轨波磨监测

在小半径曲线的内轨侧出现钢轨短波波磨加剧的现象,是世界上许多铁路网都面临的一个问题。由于地铁线路小半径曲线大量存在,受其影响尤为突出。本文为一实例研究,属于一个研发预测曲线地段钢轨波磨的数值工具课题的一部分。在斯德哥尔摩地铁中一处半径为120m的曲线段上,通过重复测试轨道的粗糙度及列车通过时引起的噪声,监测波磨的发展状况。在一年的打磨过程中,发生了剧烈的短波波磨,最大峰-峰值约为0.15mm。测试数据谱分析显示,在4～14cm波长范围内,粗糙度幅值较大,峰值约在5和8cm处。波磨为单一的纵向形式（波峰与轨道方向垂直）,幅值在100m长的被测轨道段上呈现不规则变化。粗糙度增长速率随时间增加,直至钢轨打磨后的300天,此后仅有少量的附加粗糙度出现。由于平均车速约为30km/h,因此由波磨造成的滚动噪声主要处于200Hz以下的低频段。打磨后的139～300天,4～14cm波长范围内粗糙度级增加10.1dB,与之相应的60～200Hz频段内的滚动噪声级增加4.9dB。在干燥天气条件下,列车通过时引起人体不适的噪声主要是车轮啸鸣噪声而非滚动噪声。     

Simulation of vertical dynamic vehicle–track interaction using a two-dimensional slab track model

The vertical dynamic interaction between a railway vehicle and a slab track is simulated in the time domain using an extended state-space vector approach in combination with a complex-valued modal superposition technique for the linear, time-invariant and two-dimensional track model. Wheel–rail contact forces, bending moments in the concrete panel and load distributions on the supporting foundation are evaluated. Two generic slab track models including one or two layers of concrete slabs are presented. The upper layer containing the discrete slab panels is described by decoupled beams of finite length, while the lower layer is a continuous beam. Both the rail and concrete layers are modelled using Rayleigh–Timoshenko beam theory. Rail receptances for the two slab track models are compared with the receptance of a traditional ballasted track. The described procedure is demonstrated by two application examples involving: (i) the periodic response due to the rail seat passing frequency as influenced by the vehicle speed and a foundation stiffness gradient and (ii) the transient response due to a local rail irregularity (dipped welded joint).     

Gendered immobility: influence of social roles and local context on mobility decisions in Pakistan

This paper examines the instances of one-day immobility in Pakistan and reports its socio-demographic determinants using the nationally representative dataset of the 2007 Pakistan Time Use Survey. Of 37,830 time diary respondents, nearly 30% did not report travel during the diary day. Homemakers and those out of the workforce were more likely to be immobile than employed or student respondents. Immobility rates were very high among women (55%) as compared to men (4%). Among women, those between 20 and 34 years of age, married, with children, having better education, dependent on other household members and those living in higher income households were more likely to be immobile. The excessive gender nature of immobility seems to be triggered by a gender-based sociocultural environment, which restricts female mobility due to family honor concerns. Other than this, those living in the provinces of Sindh and Khyber Pakhtunkhwa or in urban areas were more likely to be immobile than those living in Punjab and Sindh provinces or in rural areas. The significant geographic effect at broader spatial scale is caused by the demographic structure as well as due to differences in the social and cultural context of these areas. Finally, questions regarding the measurement of immobility and the potential implications of increased female immobility are discussed.     

The use of a hazard-based duration model for imputation of missing personal income data

This paper suggests using a proportional hazard model to predict personal income, for the purpose of imputing missing income data in household travel surveys. The model has a hazard function that comprises two multiplicative components: (1) a non-parametric baseline hazard function that is dependent only on the income level and (2) a function that is dependent only on the other personal attributes of the survey respondents (excluding income). To estimate and validate the model, data is drawn from a travel characteristics survey conducted in Hong Kong in year 2001. The model is found to have a much higher accuracy when compared with a conventional ordered probit model based on the assumption that the logarithm of income is normally distributed.

Adaptation planning for climate-resilient urban infrastructures

This paper analyzes the interdependency across two critical infrastructures of transportation and motor fueling supply chains, and investigates how vulnerability to climatic extremes in a fueling infrastructure hampers the resilience of a transportation system. The proposed model features both a bi-stage mathematical program and an extension to an ‘α-reliable mean-excess’ regret model. The former aspect allows decision makers to optimize the pre-disaster asset prepositioning against the maximum post-disaster system resilience. The latter aspect of the proposed model devalues the impact of ‘low-probability, high-cost’ sub-scenarios upon model results. The model reveals the reliance of post-disaster urban mobility on the interdependent critical infrastructure of motor fueling supply chains. The results also suggest how investment in the fueling infrastructure’s vulnerable elements protects urban mobility while the transportation network is stressed or under attack.     

Understanding the modifiable areal unit problem and identifying appropriate spatial unit in jobs–housing balance and employment self-containment using big data

Transportation - Jobs–housing balance (JHB) and employment self-containment (ESC) have been used to examine the jobs–housing relationship. However, the effect of the modifiable areal...     

Gender inequality in mobility and mode choice in Pakistan

Using the nationally representative dataset of the 2007 Pakistan Time-Use Survey, this paper examines gender differences in daily trip rate, mode choice, travel duration, and purpose of travel, which are previously unreported because of limited data availability. Wide gender mobility gaps are observed in the country, where women are less likely to travel, are half as mobile as men and may rely heavily on walking. The particular social and cultural context of the country, that renders women as private, secluded and family honor, seems influential in shaping their mobility and choice of activities. Demographic factors such as age, household income, and marital status significantly decrease female mobility levels. Hence, these findings call for a gender-based culturally responsive transportation policy in the country.