Yusak O. Susilo

The promises of big data and small data for travel behavior (aka human mobility) analysis

The last decade has witnessed very active development in two broad, but separate fields, both involving understanding and modeling of how individuals move in time and space (hereafter called “travel behavior analysis” or “human mobility analysis”). One field comprises transportation researchers who have been working in the field for decades and the other involves new comers from a wide range of disciplines, but primarily computer scientists and physicists. Researchers in these two fields work with different datasets, apply different methodologies, and answer different but overlapping questions. It is our view that there is much, hidden synergy between the two fields that needs to be brought out. It is thus the purpose of this paper to introduce datasets, concepts, knowledge and methods used in these two fields, and most importantly raise cross-discipline ideas for conversations and collaborations between the two. It is our hope that this paper will stimulate many future cross-cutting studies that involve researchers from both fields.

Pedestrians' behaviour in cross walks: The effects of fear of falling and age

Pedestrians are exposed to risks when crossing roads in urban areas. The crossing behaviour of pedestrians was studied as a factor contributing to their exposure to risks on the road and to their involvement in road accidents. This work explores two specific aspects of crossing behaviour: crossing speed and head pitches-the proportion of time pedestrians point their heads down (rather than towards the traffic) when crossing a road. The last one is used as an indicator of the (lack of) attention to cross-traffic. We also explored the possible effect of fear of falling (FOF) among pedestrians, as it might be associated with slow walking, less attention to cross traffic, and more attention to the pavement and their footsteps. This paper reports on a field study that combined an observatory technique with short survey. 203 pedestrians in two sites (signalised and unsignalised crosswalks) were video recorded while crossing the road. The FOF of pedestrians and other measures of pedestrian behaviour at crosswalks were revealed by means of questionnaire. Age and gender had the most significant effects on crossing speed, and FOF had a significant effect on the proportion of downward head pitches during crossing.

Comparison of Vehicle-Ownership Models

Empirical studies on household car ownership have used two types of discrete choice modeling structures: ordered and unordered. In ordered response structures, such as the ordered logit and ordered probit models, the choice of the number of household vehicles arises from a unidimensional latent variable that reflects the propensity of a household to own vehicles. Unordered response structures are based on the random utility maximization principle, which assumes a household associates a utility value across different car ownership levels and chooses the one with the maximum utility. The most common unordered response models are the multinomial logit and probit models, but only the multinomial logit has been used in practical applications because of its simple structure and low computational requirements. Consensus among researchers on unordered or ordered structures is still lacking. Empirical studies have reported various models, including the multinomial logit, ordered logit, and ordered probit. An open question remains: Which model would better reflect households’ car ownership choices? This paper compares multinomial logit, ordered logit, and ordered probit car ownership models through a number of formal evaluation measures and empirical analysis of three data sets: the 2001 National Household Travel Survey for the Baltimore [Maryland] Metropolitan Area, the 2005 Dutch National Travel Survey, and the 2000 Osaka [Japan] Metropolitan Person Trip Data. Results show the multinomial logit model should be selected for modeling the level of household car ownership.

Comparing Rail Passengers’ Travel Time Use in Great Britain Between 2004 and 2010

ABSTRACT This paper provides a unique insight into aspects of stability and change regarding the travel time use of rail passengers in Great Britain between 2004 and 2010. Empirical evidence is presented on how rail passengers spend their time, how worthwhile they consider their time use to be, the extent of advance planning of their time use and how equipped for time use they are in terms of the items they have to hand when they travel. The results reveal a consistent dominance of reading for leisure, window gazing/people watching and working/studying as favoured travel time activities. Over the six-year period, the availability and use of mobile technologies has increased. Listening to music in particular has doubled in its incidence suggesting an increasing capacity for travellers to personalise the public space of the railway carriage. Most notably the analysis reveals a substantial increase in the proportion of travellers overall making very worthwhile use of their time.

How Far Is Too Far? Travel Time Ratios for Activity Participation in the Netherlands

It is widely believed that providing activity locations close to residential locations reduces the travel time of residents. However, it has not been clear how close to one another activity locations and residential locations should be. The Dutch National Travel Survey and a travel time ratio index were used to measure acceptable travel times in relation to duration times of various activities. The results show that the value of an individual travel time ratio depends on the type of activity, individual commitments, available travel mode, and activity locations. Each activity has a unique tradeoff relationship between activity duration and travel time. Each activity also has its own turnover point–-a point at which increased activity duration will lead to less instead of more travel time. The analysis also shows that the travel time ratio value is influenced not only by an individuals activity commitments, resources, and constraints but also by the trade-off within households.

Recurrence of Daily Travel Patterns: Stochastic Process Approach to Multiday Travel Behavior

Multiday travel behavior was examined as a stochastic process, and new empirical findings are offered on the variation of travel patterns from day to day. The analysis was based on data from a 6-week travel diary survey conducted in Germany. A small number of travel pattern classes were identified, and transitions in the patterns over a course of weeks were analyzed with Markov chain models. Transitions from a pattern to itself are frequent, particularly for nonworkers, and indicate that some patterns tend to be pursued for a large number of consecutive days. The study also reveals that individuals are heterogeneous in terms of multiday travel behavior; pattern-to-pattern transition probabilities vary substantially across individuals. Some of the observable heterogeneity is demonstrated in terms of the association between attributes of the individual and the recurrence of daily travel patterns.

The grey escape: investigating older people's use of the free bus pass

Since 2008 most older people in England have benefited from unlimited area-wide free travel by bus after the morning peak period. The official policy rhetoric supporting implementation of the measure drew significantly on the need to reduce social exclusion amongst older people. However, despite a substantial increase in the number of concessionary journeys in England and the associated cost liabilities for local authorities and possibly also operators, there is currently only limited understanding of the wide ranging effects on bus use of providing a free pass, and in particular to whom benefits from the policy accrue. In part, this circumstance results from a methodological focus by evaluation studies hitherto that has emphasised aggregate-level data, often at the expense of the very rich contextual information about how the individual benefits from using a pass. This article presents insights into the perceptions, motivations and decisions relating to use of free bus passes, highlighting the existence of both tangible and intangible benefits which arise. It offers a fresh insight into previously undefined uses and benefits derived from possessing and using a concessionary bus pass. This article concludes by noting possible policy implications of the research in the context of the UKs ageing population and for other international contexts where the transport intervention of free bus travel is being considered.

Rail passengers’ time use and utility assessment: 2010 findings from Great Britain with multivariate analysis

This paper uses data from Great Britains National Passenger Survey 2010 to examine the travel time use of rail passengers and their indicative assessment of the utility of that time use. The paper explores the impacts of individuals’ sociodemographic characteristics, the activities undertaken, and the perceived difficulties that may be faced by the travelers on their assessment of travel time use utility. The study showed that only 13% of travelers considered their travel time to be wasted time. However, this result varied by journey purpose, traveling class (first or standard class), gender, and journey length. The study showed that the positive or negative appreciation by passengers of their journey time was a result not only of various combinations of onboard activity engagements, but also of the smoothness of the overall journey experience. The ability to work or study on the train most significantly increased individual appreciation of time use. However, a delay on an individuals train journey also had a major influence on the reduction of his or her perceived value of the travel time spent. Information and communication technology devices that enable travelers to watch film or video, play games, or check e-mails were more appreciated than those devices that provide access to music, podcasts, or social networking sites. The paper joins others in questioning the assumptions made in economic appraisals that travel time is unproductive. The paper concludes with a call for more substantive and targeted data collection efforts within travel behavior research devoted to further unraveling the phenomenon of the positive utility of travel.

Behavioural decisions of travel-time ratios for work, maintenance and leisure activities in the Netherlands

Abstract Using the 2005 Dutch National Travel Survey data-set this paper investigates the influences of socio-demographics, journey patterns and built environment factors on the ratio of travel time and activity duration that an individual spends when engaging in work, daily shopping, non-daily shopping and sport/recreation activities. The results show that socio-demographics and other variables have unique influence on each type of activity. The travel-time ratios (TTRs) of some activities are more varied across the population whilst some have more ‘acceptable’ ratios. The interaction between activity duration and travel time is also unique for each socio-demographic group. For example, given the same amount of travel time, males will spend significantly less time on shopping than females; whilst for sports and recreational activities males will spend more time on than their female counterpart. By understanding individuals’ different TTR values for different activities, the TTR can be an important guide when providing activity locations which in turn can help in creating sustainable urban transport conditions.

Individual Carbon Dioxide Emissions and Potential for Reduction in the Netherlands and the United Kingdom

Using National Travel Survey (NTS) data from the Netherlands and the United Kingdom, this paper examines how passenger transport emissions are divided across society and how similar this distribution is across these two countries. By looking across a series of data over time, the paper examines the relationships between socioeconomic characteristics and individual greenhouse gas emissions, the stability of these relationships over time, and the extent to which these relationships are similar in these two countries. Suitable policy measures for different socioeconomic groups are then examined. The general effectiveness and acceptability of these measures are then discussed by drawing on pan-European (Euro-barometer) survey results. Analyses of the NTS data reveal that about 10% of the Dutch population is responsible for almost half of all travel-related carbon dioxide (CO2) emissions in the Netherlands. Similarly, in the United Kingdom, about 20% of the population is responsible for 60% of the passenger–transportation-related CO2 emissions. Analysis of pan-European opinion surveys shows that there is a clear awareness among the majority of the population that the type of car and the way in which it is used have important impacts on the environment. Despite this awareness, however, only a minority seem prepared to take action to reduce the environmental consequences of their travel behavior. The study supports the argument that the willingness to change behavior is a complex mixture of individual and social interests. A major challenge is how to encourage changes in behavior to reduce transport emissions with the right policies at the right time in the right place.