Estimating potential increases in travel with autonomous vehicles for the non-driving,elderly and people with travel-restrictive medical conditions

Automated vehicles represent a technology that promises to increase mobility for many groups, including the senior population (those over age 65) but also for non-drivers and people with medical conditions. This paper estimates bounds on the potential increases in travel in a fully automated vehicle environment due to an increase in mobility from the non-driving and senior populations and people with travel-restrictive medical conditions. In addition, these bounding estimates indicate which of these demographics could have the greatest increases in annual vehicle miles traveled (VMT) and highlight those age groups and genders within these populations that could contribute the most to the VMT increases. The data source is the 2009 National Household Transportation Survey (NHTS), which provides information on travel characteristics of the U.S. population. The changes to light-duty VMT are estimated by creating and examining three possible travel demand wedges. In demand wedge one, non-drivers are assumed to travel as much as the drivers within each age group and gender. Demand wedge two assumes that the driving elderly (those over age 65) without medical conditions will travel as much as a younger population within each gender. Demand wedge three makes the assumption that working age adult drivers (19–64) with medical conditions will travel as much as working age adults without medical conditions within each gender, while the driving elderly with medical any travel-restrictive conditions will travel as much as a younger demographic within each gender in a fully automated vehicle environment. The combination of the results from all three demand wedges represents an upper bound of 295 billion miles or a 14% increase in annual light-duty VMT for the US population 19 and older. Since traveling has other costs besides driving effort, these estimates serve to bound the potential increase from these populations to inform the scope of the challenges, rather than forecast specific VMT scenarios.     

Elderly travel frequencies and transport mode choices in Greater Rotterdam,the Netherlands

Demographic ageing is a key societal challenge in Europe as well as in many other western and non-western societies. A crucial dimension concerns elderly daily mobility patterns. While still partaking fewer and shorter trips than younger generations, today’s elderly have been found increasingly (auto)mobile. Although the elderly benefit from the independence, freedom of movement, and social inclusion, concerns may rise regarding the environmental and accessibility impacts of this induced mobility. The present study adds to the expanding literature on elderly mobility, an integrated analysis of the effects of socio-demographic, health, trip, spatial and weather attributes on elderly mobility. Utilizing travel diary data for Greater Rotterdam, The Netherlands, trip frequencies and transport mode choices of the elderly are analysed by means of zero-inflated negative binomial models as well as multinomial logit regression models, and contrasted to the non-elderly subpopulation to explore (dis)similarities. While the results show common determinants, the models also highlight important differences in the magnitude of the estimated coefficients and factors only influencing transport patterns for the elderly. Embedded in the context of an aging population, the empirical findings assist policy-makers and planners in several respects: For transportation plans and programs it is critical to recognize mobility needs of the elderly. As the seniors are becoming increasingly automobile, the results call for strategies to encourage older people to use more physically active and environmentally friendly transport modes such as public transport, walking and cycling.     

Mobility behavior of the elderly: an attitude-based segmentation approach for a heterogeneous target group

The western population is ageing. Based on the assumption that the elderly are a quite heterogeneous population group with an increasing impact on the transport system, mobility types of the elderly were identified. By means of 1,500 standardized telephone interviews, mobility behavior and possible determinantes including infrastructural, sociodemographic and attitudinal variables, were assessed. The most important factors, identified by five regression analyses, served as type-constituent variables in a series of cluster analyses. The final cluster solution resulted in four segments of the elderly named Captive Car Users, Affluent Mobiles, Self-Determined Mobiles, and Captive Public Transport Users. The groups showed distinct mobility patterns as well as significant differences in infrastructural, sociodemographic and attitudinal variables. The study provides a more comprehensive understanding of the diverse lifestyles, attitudes, travel behavior and needs of the elderly. Furthermore, it identifies starting points for the reduction of car use.     

Leisure mobility styles in Swiss conurbations: construction and empirical analysis

Leisure travel is the most difficult travel purpose to analyse due to the lack of fixed spatial and temporal referents and the consequent flexibility in patterns. This paper addresses lifestyles, social influence, and the travellers’ social networks, issues that have proved valuable for travel behaviour research in confronting the complexity of leisure travel. An approach for constructing leisure mobility styles, based on orientations towards leisure and mobility, will be presented first and then the hypotheses that transport behaviour can be better explained through analysis of leisure mobility styles will be tested. Multivariate analysis reveals that the leisure mobility style group makes a significant contribution towards clarifying variance for the activities ‘Visiting friends and relatives’, ‘Travel participation’, ‘Mode choice’, and ‘Travel distance for leisure’. The use of leisure mobility styles is most useful for developing practical intervention pointers where the in-group homogeneity of lifestyle should be addressed in greater detail.     

Spatial structure and mobility

The aim of this paper is to contribute to a clearer understanding of the extent to which the spatial structure and planning of the residential environment can explain mobility, in general, and the choice of mode of transport, in particular, and what spatial planning and traffic management aspects play a significant role in this. The research showed that certain aspects of the planned environment do indeed have a clear impact on mobility. These effects are particularly apparent in trips made for shopping and social or recreational purposes. It is mainly personal characteristics that largely or almost entirely determine commuter traffic. An integral approach to the planning of residential areas is required to achieve any great changes in mobility. Only then may we expect spatial planning to have any significant impact on car use.     

A comparative analysis of transportation-based accessibility to mental health services

The demand for mental health services has been growing stronger over the last couple of decades. This indicates the need to study and assess the access to these mental health services especially with a focus on the vulnerable populations having the greatest need. As such, this paper presents a Geographical Information Systems (GIS)-based analysis in order to study and evaluate the accessibility of mental health facilities using the information on the spatial distributions of population and facilities, and regional traffic characteristics. For this purpose, different age group segments are utilized including the total population as well as those aged between 18 and 21, 22 and 49, 50 and 64, and those aged over 65 and 85. Focusing on the State of Florida, spatially detailed accessibility metrics are calculated with regard to healthcare facilities using travel times between population block groups and these critical mental health facilities. These estimates are used to calculate the weighted county accessibility scores for each county. Findings clearly delineate those counties that lack access to mental facilities, especially those in Northwest Florida, a demographically diverse and substantially rural region. This type of analysis can help planners and policy makers develop better strategies in order to provide adequate mental health care options needed in targeted locations.     

A comprehensive study of life course,cohort, and period effects on changes in travel mode use

This paper studies changes in people’s travel mode use from one year to the next. It is informed by three distinct discourses: travel behaviour change, the mobility biographies approach, and cohort analysis. The data used is the German Mobility Panel (GMP) 1994–2008 in which households and their members are asked three times in three subsequent years to report the trips they made over a week. The changes reported are regressed to key events over the life course, cohort effects and period effects, while various sociodemographic and spatial attributes are controlled. Due to the non-independent nature of panel observations, a cluster-robust regression approach is used. The findings suggest that behind the aggregate stability in travel mode use over time there is much change ‘under the surface’, induced by life course changes, individual and household sociodemographic, and spatial context. The changes found induced by life course related key events favour the notion of mobility biographies. However, taken over all key events seem to be relatively loosely associated with mode use changes. Nonetheless, various significant effects of baseline variables suggest that mode use may change even in the absence of a key event.     

Large-scale transit market segmentation with spatial-behavioural features

Transit market segmentation enables transit providers to comprehend the commonalities and heterogeneities among different groups of passengers, so that they can cater for individual transit riders’ mobility needs. The problem has recently been attracting a great interest with the proliferation of automated data collection systems such as Smart Card Automated Fare Collection (AFC), which allow researchers to observe individual travel behaviours over a long time period. However, there is a need for an integrated market segmentation method that incorporating both spatial and behavioural features of individual transit passengers. This algorithm also needs to be efficient for large-scale implementation. This paper proposes a new algorithm named Spatial Affinity Propagation (SAP) based on the classical Affinity Propagation algorithm (AP) to enable large-scale spatial transit market segmentation with spatial-behavioural features. SAP segments transit passengers using spatial geodetic coordinates, where passengers from the same segment are located within immediate walking distance; and using behavioural features mined from AFC data. The comparison with AP and popular algorithms in literature shows that SAP provides nearly as good clustering performance as AP while being 52% more efficient in computation time. This efficient framework would enable transit operators to leverage the availability of AFC data to understand the commonalities and heterogeneities among different groups of passengers.     

Sustainability assessment of inland transportation in China: A triple bottom line-based network DEA approach

The transport sector accounts for nearly one third of the world’s total energy use, while inland transport alone is responsible for half of the global petroleum consumption. The expansion of motorization in newly industrialized economies necessitates setting realistic targets. To support decision-makers in better assessment of transport sustainability performance, we introduce a systematic triple bottom line-based approach to evaluate inland transport, considering social, economic, and environmental dimensions of sustainability. The proposed network data envelopment analysis (DEA) measure organizes the three components of the system into a parallel structure, allocates shared input across subsystems, and incorporates undesirable output. The empirical application determines the efficiency of regional inland transportation systems in China from 2006 to 2015. The results indicate a rise in overall transport efficiency between China’s 11th and 12th five-year development plan periods and link the economic growth with a decrease in environmental transport efficiency in the Central and Western zones and with a decline in social efficiency in the Eastern zone. Since 2012, the social sustainability remains the weakest component of inland transport, which requires special attention by policy-makers to support vulnerable groups of transport users. This study provides further insight into the investigated measures and proposes recommendations for the improvement of inland transport in China.     

Walking short distances. The socioeconomic drivers for the use of proximity in everyday mobility in Barcelona

Many studies have found that cities, with residents that are co-located with jobs and services in compact and diverse urban environments, generate positive outputs for a number of areas of social policy, with issues ranging from environmental to social and including public health. This evidence supports promoting rich and thriving neighbourhoods in order to encourage short distance mobility. In this context, we use a wide travel survey (EMQ06), undertaken in Spain, to measure short-distance travelling within Barcelona and to assess how distinct social groups make use of the local scale for their everyday mobility. The effects of socioeconomics and access to transport are discussed, prior to applying a Chi-squared Automatic Interaction Detection (CHAID) method, in order to explore heterogeneity among the different social groups, in terms of local travelling. We found that nearly a quarter of all daily mobility in Barcelona is performed with a local trip, and that short trips are more frequently undertaken for personal purposes. Also, age, gender and access to private transport appear as significant factors. Overall, our results suggest that a proximity scale is being used by those groups with greater time–space constraints, such as working women or low income people without access to private vehicles, opening important implications on transport policy regarding the design of proximity-prone environments.     

Relationship between well-being and daily time use of elderly: evidence from the disabilities and use of time survey

According to US Census Bureau, the number of individuals in the age group above 65 years is expected to increase by more than 100% from the year 2000 to 2030. It is anticipated that increasing elderly population will put unforeseen demands on the transportation infrastructure due to the atypical mobility and travel needs of the elderly. Consequently, transportation professionals have attempted to understand the travel behavior of the elderly including the trip frequency, trip distance and mode choice decisions. Majority of the research on elderly travel behavior have focused on the mobility outcomes with limited research into understanding the tradeoffs made by this population segment in terms of their in-home and out-of-home activity engagement choices. The goal of the current research is to contribute to this line of inquiry by simultaneously exploring the daily activity engagement choices of the elderly Americans including their in-home and out-of-home activity participation (what activities to pursue) and time alloocation (duration of each activity) decisions while accounting for the temporal constraints. Further, the study attempts to explore the relationship between physical and subjective well-being and daily activity engagement decisions of the elderly; where subjective well-being is derived from reported needs satisfaction with life and different domains of it. To this end, data from the Disabilities and Use of Time survey of Panel Study of Income Dynamics was used to estimate a panel version of MDCEV model. In addition to person- and household-level demographic variables, activity participation and time use choices of elderly were found to vary across different levels of reported physical and subjective well-being measures. The model estimation results were plausible and provide interesting insights into the activity engagement choices of the elderly with implications for transportation policy development. Among other socio-demographic variables, living arrangements (living with family versus in elderly homes) were found to have significant influence on how people participate into different in-home versus out-of-home activities. For example, elderly living in the elderly home were found to participate more into out-of-home activities compared to people living with families. Elderly with disabilities were found to compensate lower participation into out-of-home activities with more participation into in-home activities. Considerable heterogeneity was observed in time engagement behavior of the elderly across reported levels of satisfaction with finance, job and cognitive needs. For example, elderly expressing high satisfaction with job was found to spend less time in in-home social activities. Elderly reporting higher satisfaction with finance were found to spend more time into OH social and shopping activities.     

Spatial differentiation,transport demands and transport model design in Kuwait

Foreign consultants still provide much of the analytical expertise for transport planning studies conducted in the Gulf States and other rapidly developing countries. Most of the systems analysis techniques used are adaptations of those developed for western urban areas. The populations of the Gulf States are unique in that they contain very large populations of foreign workers who have very different social and economic characteristics from the national populations. This paper describes these differences and shows how they have influenced the spatial evolution of the Kuwait metropolitan area and the associated transport demands. The paper also describes the analytical tools that are most appropriate for capturing the transport behaviour of residents of the Kuwait metropolitan area.     

Introducing multitasking to the study of travel and ICT: Examining its extent and assessing its potential importance

Personal travel is undertaken principally as a means of access. The Internet now provides an additional form of access, enabling many activities to be reached without recourse to physical mobility by the individual undertaking the activity. However, the social and transport effects of this ‘virtual mobility’ are uncertain. Here, it is argued that the incidence and properties of multitasking are a necessary part of the assessment of such impacts. Participation in activities and, thus, change in activity participation will not be fully measured without consideration of multitasking. This paper presents a review, empirical evidence and discussion to support this hypothesis. Emergent from an examination of the literature and examined by new empirical evidence are three observations: (1) failure to consider multitasking leads to the underreporting of key activities; (2) misrepresentation of activity participation tends to be more pronounced for certain groups; (3) lack of awareness of multitasking could lead to flawed measurement and misrepresentation of behaviour change. Further to these observations, study findings suggest that multitasking behaviour varies according to whether the primary activity is being undertaken online or offline. Thus, the consideration of multitasking is likely to have important implications for the study of travel, Internet use and interactions between the two.     

The mobility and accessibility expectations of seniors in an aging population

Populations of post-industrial nations are aging. With a growing number of people living well into their 80s and maintaining active lives, the transportation system will have to start focussing more closely on understanding their mobility and accessibility needs, so as to ensure that specific requirements of this large segment are not being ignored through the promotion of traditional ‘solutions’ and historical assumptions. This paper takes a close look at the evidence on the mobility needs and travel patterns of individuals over 64, distinguishing between the “young” elderly (aged 65–75 years) and the “old” elderly (over 75 years). This distinction is particularly useful in recognising the threshold of health change that impacts in a non-marginal way on mobility needs. This distinction also focuses transport planning and policy on a commitment to understanding the different needs of these sub-groups of the population, identifying services and facilities that better cater for these groups. We review the evidence, in particular, on the mobility characteristics of the over 75 years age group, including how they secure support through migration and settlement patterns. We use the empirical evidence from a number of western nations to identify the role of conventional and specialised public transport as an alternative to the automobile in meeting mobility and accessibility needs.     

Understanding urban mobility patterns with a probabilistic tensor factorization framework

The rapid developments of ubiquitous mobile computing provide planners and researchers with new opportunities to understand and build smart cities by mining the massive spatial-temporal mobility data. However, given the increasing complexity and volume of the emerging mobility datasets, it also becomes challenging to build novel analytical framework that is capable of understanding the structural properties and critical features. In this paper, we introduce an analytical framework to deal with high-dimensional human mobility data. To this end, we formulate mobility data in a probabilistic setting and consider each record a multivariate observation sampled from an underlying distribution. In order to characterize this distribution, we use a multi-way probabilistic factorization model based on the concept of tensor decomposition and probabilistic latent semantic analysis (PLSA). The model provides us with a flexible approach to understand multi-way mobility involving higher-order interactions—which are difficult to characterize with conventional approaches—using simple latent structures. The model can be efficiently estimated using the expectation maximization (EM) algorithm. As a numerical example, this model is applied on a four-way dataset recording 14 million public transport journeys extracted from smart card transactions in Singapore. This framework can shed light on the modeling of urban structure by understanding mobility flows in both spatial and temporal dimensions.     

Investigating Links between Social Capital and Public Transport

Abstract

Social capital (SC) describes the advantage individuals and communities can gain from social participation, mutual assistance and trust. The provision of travel options for those who are socially disadvantaged is a major rationale for providing public transport. While there has been recent work on how transport can address social exclusion, SC has been overlooked. This article describes the theoretical basis of SC and suggests ways in which the concept might relate to public transport planning, research and practice. Disadvantaged groups can lack SC, mobility and accessibility. Public transport can provide mobility for this group and, in doing so, provide a greater opportunity to create social networks, trust and reciprocity. Although these concepts are abstract, plausible links are identified between the concepts of enhanced positive social interaction associated with the ‘livable city’ concept and those engendered in SC theory. Public transport by definition involves travelling with others and hence provides opportunities for social interaction while travelling. While a series of possible links between SC and public transport are theorized, it is unlikely these are necessarily strong since other mobility options are available and a range of land‐use and non‐transport alternatives can address social needs. Aspects of the SC concept are already covered by the social mobility and accessibility literature, although it does offer a wider insight into the potential advantages of improving access and mobility for disadvantaged communities. The concept of SC is complex and suffers from a ‘fuzzy’ definition. There is a lack of quantitative primary research associated with measuring SC. Measuring the influence of improved mobility options on SC in disadvantaged communities would be a worthwhile research area. Despite the challenges associated with researching SC, the links between SC and travel present an opportunity to understand how public transport acts to address social disadvantage through the provision of mobility to disadvantaged communities.     

Lifestyles and transportation needs of the elderly in Los Angeles

This study examined the trip-making behavior of persons over 65 years of age residing in Los Angeles County. To date, the major shortcoming of most research concerned with the transportation needs of the elderly is that the aged have been treated as a homogeneous group without recognizing the various lifestyles of the senior population. The two most easily distinguishable groups of elderly persons within the county are those residing in the inner-city and those around the urban fringe. Although many elderly are still found in gray ghettos there is currently a trend toward a more suburban generation of retirees. Four areas were selected within the county that reflected these two living patterns of the elderly. A comparative analysis of trip patterns and socio-economic data was completed. It was found that the suburban elderly are characterized as (1) having higher incomes, (2) residing predominantly in single-family units and (3) being reliant upon automobile transportation. As is typical of a large proportion of those over 65 years of age, many of the suburban elderly cannot drive. Studies of the transportation needs of this group indicate that without transit alternatives they may well become society's most transit-deprived segment. On the other hand, while the inner-city elderly may have a wider range of transportation options, they also have a distinct economic disadvantage which preludes their accessibility to opportunities. An analysis of modal choices, trip purposes and the frequency of travel exhibited many similarities and some significant differences in the travel behavior as well as problems of these two groups.In addition to investigating travel patterns a survey of taxi-cab use on weekends and weekdays was undertaken. Elderly persons represent a substantial proportion of taxi-cab patrons. Their use of taxis is further indicative of the change that occurs in mobility patterns upon reaching retirement. This mode of transportation is presently the only type of demand-responsive service available to the senior population in some parts of the county.This report was produced as part of a program of Research and Training in Urban Transportation sponsored by the Urban Mass Transportation Administration of the U.S. Department of Transportation. The results and views expressed are the independent products of university research and are not necessarily concurred in by the Urban Mass Transportation Administration of the Department of Transportation.     

A method to evaluate equitable accessibility: combining ethical theories and accessibility-based approaches

In this paper, we present the case that traditional transport appraisal methods do not sufficiently capture the social dimensions of mobility and accessibility. However, understanding this is highly relevant for policymakers to understand the impacts of their transport decisions. These dimensions include the distribution of mobility and accessibility levels over particular areas or for specific population groups, as well as how this may affect various social outcomes, including their levels of participation, social inclusion and community cohesion. In response, we propose a method to assess the socially relevant accessibility impacts (SRAIs) of policies in some of these key dimensions. The method combines the use of underlying ethics principles, more specifically the theories of egalitarianism and sufficientarianism, in combination with accessibility-based analysis and the Lorenz curve and Gini index. We then demonstrate the method in a case study example. Our suggestion is that policymakers can use these ethical perspectives to determine the equity of their policies decisions and to set minimum standards for local transport delivery. This will help them to become more confident in the development and adoption of new decision frameworks that promote accessibility over mobility and which also disaggregate the costs and benefits of transport policies over particular areas or for specific under-served population groups.