Jimmy Armoogum

Continuous Mobility Surveys: The State of Practice

Abstract In this paper we challenge the prevailing practice of conducting one‐off cross‐sectional mobility surveys, making a case for change on the basis of usefulness and cost‐effectiveness. We believe that urban areas over say, one million inhabitants, should collect mobility data on a continuous basis as part of their efforts to guarantee sustainable development. This would allow them to gain a proper understanding of the pressing environmental and transport‐related issues of today’s world, as well as of the effects of economic growth and price (especially for fuel) volatility. In our scope we include panel data (i.e. information from a smaller sample of respondents who are interviewed at different points in time, hopefully during several years), as this type of information is unique in its ability to help understanding behavioural changes and the impact of time‐related effects, such as habit and inertia. We revise the state of affairs in different parts of the world, not limiting ourselves to urban data.

Immobility and mobility seen through trip-based versus time-use surveys

Abstract Nationwide Transport Surveys and Time‐Use Surveys both reflect the daily agendas and schedules of the reporting individuals and should therefore yield comparable indicators of travel behaviour; for instance: immobility rate (share of persons not leaving the home on any one day), daily travel time, and number of trips per day. These two surveys exist in three countries from the same time period: Belgium, France, Great Britain. The comparisons demonstrate that they tell parallel stories, but that the levels of the variables are significantly different with lower immobility rates and longer travel times reported in the Time‐Use Surveys. These surveys should therefore be integrated in the analysis of travel behaviour analysis as a crucial yardstick. In Europe, where Nationwide Travel Surveys are intermittent and not harmonized, the harmonised Time‐Use Surveys allow for crucial European‐wide comparisions across time and space.

Projection of the Daily Travel of an Ageing Population: The Paris and Montreal Case, 1975–2020

Abstract Ageing of the population, urban sprawl and car dependency will change travel patterns. The main objective of this paper is to give elements for a better understanding of the impact of changing demographics on the long‐term evolution of daily mobility using demographic‐based models to forecast, for the elderly population, car‐ownership, trip frequency, distance travelled, average trip distance. A second objective is to measure the impact of the long‐term tendencies observed on the appearance of new needs of travel demand such as a rapid increase of demand‐responsive transport. The paper compares two agglomerations, both in a strong ageing process, but in cultural contexts: a large European metropolis, Paris; and a medium sized North‐American city, Montreal. Many common conclusions derived from the two different cases studies reinforce the possibility of generalizing the conclusions to other situations.

Vers la saturation ? Une approche démographique de l'équipement des ménages en automobile dans trois régions urbaines

Bussiere (Yves), Armoogum (Jimmy), Madre (Jean-Loup). - i Hacia la saturacion ? Un anali- sis demografico del equipamiento automovilistico de los hogares en tres regiones ur- banas Partiendo de los limites de alcance dinamico de los modelos clasicos, que a menudo se basan en una estimacion transversal de los efectos de renta, los autores elaboran un analisis longitudinal basado en el seguimiento del comportamiento de generaciones sucesi- vas a lo largo de su ciclo de vida. El articulo ofrece una sintesis de las proyecciones a largo plazo de la motorizacion de los hogares en Ile-de-France (11 millones de habitantes), la region metropolitana de Montreal (3 millones) y la region urbana de Grenoble (0,5 millones). La historia de la motorizacion, mas antigua en America del Norte que en Europa, cla- rifica el concepto de saturacion (disminucion progresiva del crecimiento hacia las asimpto- tas determinadas por el modelo y no fijadas a priori). El segundo coche es en todos los casos la razon principal del crecimiento del parque automovil y la expansion urbana hace prever una explosion del numero de vehiculos en la periferia ; el crecimiento seria mucho mas moderado en las zonas densas.

Generating Internationally Comparable Figures on Long-Distance Travel for Europe

This paper discusses available household survey data on long-distance travel (LDT) and presents harmonized figures on LDT in Europe. First, there is a comparison of the results of different household travel surveys about LDT. The findings of this comparison have important implications for the methodology of surveying LDT: conventional mobility diary surveys are better than LDT surveys in capturing journeys up to 200 km. LDT surveys perform better in capturing travel only beyond 400 km. Second, the paper presents the first internationally comparable figures on LDT demand for Europe. These figures have been compiled by using different sources of information, avoiding the drawbacks of the different surveys. The results indicate that in northern and central Europe there is higher demand for LDT than in the south. Moreover, the results illustrate how policies and public-transport supply affect the modal split in LDT: in countries with a high-quality railroad supply, such as Switzerland, the railroad share is significantly higher than in other countries. Countries with a liberalized, interurban bus market, in contrast, have a significantly higher bus mode share.

Potential for Car Use Reduction Through a Simulation Approach: Paris and Lyon Case Studies

Abstract The aim of the present study is to evaluate the possible extent of modal shifts from car use to ‘alternative modes’ (public transport, cycling, walking) without any change in individual patterns of activity. Its approach is based on a transfer procedure that allows the simulation of the maximal potential market for transport modes other than the private car. The method is based on repeated iterations of a simulation model that assigns journeys to transport modes other than the automobile based on a number of improved public transport scenarios. Demand is channelled towards individual modes (walking, cycling), public transport, and a combination of individual and public modes, based on their relative time and distance performance. The modal transfer procedure is applied to several transport supply scenarios, which provide a picture of what is possible in the sphere of modal split. Each simulation entails a potential transfer of private vehicle‐km to each of the other modes. Even where different public transport scenarios are simulated, the transfer is evaluated for round trips in both the Paris and Lyon surveys. There is therefore no modification in the activity pattern of the people surveyed nor trips induced by improvements in transport supply. The aim is not to predict what would be the modal split in other circumstances, but the upper limit of the shifts. This paper presents our methodology and the principal results obtained through numerical simulations based on figures for the Paris and Lyon conurbations. This approach demonstrates that a policy focused on modal shifts has the potential to reduce car use, but that this potential is limited. Any aspiration to reduce car use further would mean changes in the patterns and loci of activity.

Calibration Strategies to Correct Nonresponse in a National Travel Survey

Nonresponse results in a reduced sample size, but a more important concern of researchers is the possible impact of nonresponse bias. Bias is introduced when those who do not respond to the survey are systematically different from those who do respond on key variables of interest. The response mechanism is defined as “ignorable” when it can be modeled with the available characteristics (e.g., from the sample base). For example, if the nonresponse mechanism depends on the level of income, the respondent sample must be reweighted according to the distribution of income to correct the nonresponse errors. For the French National Travel Survey 2007–2008, the sample was drawn directly from the census and the list of new residences built since then. Therefore, there is considerable information about respondents and nonrespondents. The response mechanism is modeled first, and then calibration strategies are discussed. The nonresponse biases are quantified by using auxiliary information in different calibration exercises.

Lessons from an Overview of National Transport Surveys, from Working Group 3 of COST 355: “Changing Behavior Toward a More Sustainable Transport System”

Abstract This chapter summarizes some of the results from the Working Group “National Travel Surveys” in COST Action 355. All 50 presentations could not be reviewed here; thus, we focus on three crucial topics: the periodicity of data collection, but also its longitudinal aspects (advantages of continuous surveying, repeated cross-sections vs. panel surveys, etc.), new technologies for improving the efficiency and accuracy of mobility surveys (computer-assisted telephone, Web-based, interviews, GPS, GSM, RDS, etc.), innovative approaches, exemplified by qualitative surveys combined with conventional quantitative ones, and by biographical approaches.

Measuring Uncertainty in Long-term Travel Demand Forecasting From Demographic Modelling: Case Study of the Paris and Montreal Metropolitan Areas

Uncertainty on traffic forecasts may have an impact on reimbursement scheduling for investment, as well as for scenarios for operating costs. Even the best projections are based on models and assumptions, thus raising the question of their accuracy. Indeed, long term investments are risky and it is important to cope with uncertainty. This paper deals with the uncertainty on a long term projection with an Age-Cohort approach. The authors used the jackknife technique to estimate confidence intervals and observe that the demographic approach outlines the structural determinants for long term trends of mobility.