L Miguel Martínez

Effects of the Modifiable Areal Unit Problem on the Delineation of Traffic Analysis Zones

Transportation analysis is typically thought of as one kind of spatial analysis. A major point of departure in understanding problems in transportation analysis is the recognition that spatial analysis has some limitations associated with the discretization of space. Among them, modifiable areal units and boundary problems are directly or indirectly related to transportation planning and analysis through the design of traffic analysis zones (TAZs). The modifiable boundary and the scale issues should all be given specific attention during the specification of a TAZ because of the effects these factors exert on statistical and mathematical properties of spatial patterns (ie the modifiable areal unit problem—MAUP). The results obtained from the study of spatial data are not independent of the scale, and the aggregation effects are implicit in the choice of zonal boundaries. The delineation of zonal boundaries of TAZs has a direct impact on the reality and accuracy of the results obtained from transportation forecasting models. In this paper the MAUP effects on the TAZ definition and the transportation demand models are measured and analyzed using different grids (in size and in origin location). This analysis was developed by building an application integrated in commercial GIS software and by using a case study (Lisbon Metropolitan Area) to test its implementabiity and performance. The results reveal the conflict between statistical and geographic precision, and their relationship with the loss of information in the traffic assignment step of the transportation planning models.

Configuration of Innovative Minibus Service in the Lisbon, Portugal, Municipality: Spatial–Temporal Assessment

The viability of implementing a new alternative intermediate transport mode in the Lisbon, Portugal, metropolitan area was examined. The intention of this new system was to combine the major strengths of both public transport and private vehicles to provide a competitive transport alternative for commuters from low and intermediate density areas, who do not create enough demand to sustain a high-quality public transport service. Conventional public transport systems can provide efficient space and energy consumption, whereas private vehicles have high levels of flexibility and are fast and always available. A comprehensive methodology is presented to encompass the generation of input data of the model on the basis of transport demand data involving spatial-temporal constraints, the possible location of the service stops, and the detailed characterization of the service operation. The global objective of the model is to design a self-sustainable system that would maximize the operators profit, not one that would satisfy all potential demand. The developed model uses supply parameters obtained through current bus operators in the region. However, the estimated values should be refined before service deployment. This assessment was performed, as an initial test bed for Lisbon and will be expanded to the whole metropolitan area. Results suggest that this service might be significantly profitable to the operator and a good alternative for single private car drivers. Implementation of this system may relieve some congestion during peak periods.

Impacts of Short-Term Land Use by High-Speed Rail on Large Metropolises: Case Study of Madrid, Spain

An accessibility-based approach was used to find the short-term impacts of high-speed rail (HSR) on metropolitan areas. The impacts of Spanish HSR on Madrid from 2006 to 2009 were studied by the integration of geographic information system technology and spatial discrete choice models. Besides the socioeconomic variables, both local and regional transport network development and accessibility growth were considered to isolate the impacts on the changes of land use types brought about by different sources of accessibility. The results from the model reveal that in large metropolitan cities such as Madrid, the impacts of HSR were shadowed by other external factors. With a focus on the land typologies that shifted the land use types during the years studied, the growth of regional accessibility by inauguration of new HSR lines was found to be an important incentive. This growth of regional accessibility may lead to the upgrade of land occupation. However, this finding does not imply that such an increase can be a sufficient factor to drive the change in land use patterns because in a comparison with the whole metropolitan region, the proportion of land cells that changed each year was relatively small.

Measuring Satisfaction with Transit and Car Trips with Use of One Logistic Regression Model

The aim of this research was to identify and quantify the elements that influenced the trip satisfaction of people traveling by public transport, private car, or both. The data used in this research came from a revealed preference survey designed for global use and conducted in 2014, with most responses coming from Lisbon, Portugal, and Thessaloniki, Greece. These data include sociodemographic characteristics, public transport preferences, and trip characteristics obtained from trip diaries. A generalized logistic regression model was developed to assess the average trip satisfaction for all transit alternatives and the private car. In this model, satisfaction was expressed as a probability of satisfaction in 100 Bernoulli trials, and a final satisfaction rating was created. The results indicate that individual trip-specific attributes, such as crowdedness and traffic, are more important than network characteristics and performance. Attributes fixed for a specific trip, such as access time and parking costs, or having small variability, such as waiting time for the subway, are found to be completely insignificant with relation to satisfaction. The results also suggest that attributes affecting service reliability and comfort are the ones users value higher with respect to satisfaction. A conclusion one might draw from the results is that the characteristics of a transit system or road network do not affect trip satisfaction. These elements could play a more important role in the mode choice process, but the attributes that may vary from trip to trip are the ones that seem to affect trip satisfaction.