Few studies have analyzed the mobility impacts of TOD using a longitudinal research approach, and even fewer incorporated origin–destination (OD) information in the analysis. In this paper, we examine the impacts of a metro system with TOD features on the share of car and bus trips using Metro do Porto as a case study. The application of an autoregressive beta regression modeling approach to parish and OD data from two mobility surveys (2000 and 2017) allowed to detect changes in travel behavior accounting for pre-metro mode shares. Metro implementation was associated with strong reductions of the share of car trips in OD pairs with metro at both trip ends, especially when stations were TOD. Metro influence on the share of bus trips varied from neutral to positive, suggesting that bus and metro complement each other rather than compete for passengers.

Transit-oriented development (TOD), an urban planning concept that aims to promote sustainable transport modes, has been actively studied in recent years, especially in relation to car trips reduction. However, longitudinal studies on the matter are still rare. In this paper, we analyze the effects of the implementation of a new metro system after its first 10 years of operation focusing on how changes in the number of car trips were influenced by station type–TOD, transit-adjacent development (TAD) and park-and-ride (P&R). Specifically, we perform a before/after analysis of the impact of metro implementation in the Porto area (Portugal) both at a macro scale (civil parish) and at a micro scale (census tract) to analyze the overall effect of metro and more detailed effects only detectable at the micro scale. Census-tract data enables a comprehensive analysis of spatial spillover impacts from different stations, comparing the extent (i.e., the distance range within which the effect of station proximity is noticeable) and the magnitude (the reduction in the number of car trips) of the spillover in each case. Both direct and indirect metro impacts are already visible at the macro scale, yet at the micro scale the magnitude of the spillover effects varies depending on station type. The effects of TOD stations on the reduction of car trips are the strongest across the different station types and are felt up to a 2 km distance from a station, while TAD and P&R effects are weaker and do not reach beyond 1.2 km.

Transit-oriented development has been widely studied in recent years as a means to reduce car trips and promote sustainable transport modes. However, longitudinal studies on the matter are still rare. This paper contributes to longitudinal research of Transit-Oriented Development (TOD) effects on travel behavior by analyzing the evolution of the number of car trips after the implementation of a light-rail metro system in the Porto region (Portugal). As Metro do Porto is a large infrastructure project (a metro network of 67 km), we relied on a macro-analysis performed at the civil parish level. Changes in the number of car trips are evaluated using a difference-in-differences model, extended to a spatial model to account for the metro's spillover effects. These effects became obvious as metro ridership is reported not only in the directly metro-served parishes but also in adjacent non-served parishes. The results highlight the importance of the metro system in reducing the number of car trips, and this effect is visible not only in metro-served parishes but also in the neighboring ones, which are not directly served by the new transport system. Furthermore, we compare the performance of parishes predominantly served with TOD stations to those with transit-adjacent (TAD) and park-and-ride (P&R) stations. We conclude that both station types can reduce the number of car trips, yet only TOD parishes generated significant spillover effects. The importance of other potentially influential factors like building density or socio-economic characteristics is also discussed.

Among the attempts made worldwide to foster urban and transport sustainability, transit-oriented development (TOD) certainly is one of the most successful. Since the TOD concept appeared in the late 1980s, it has received increasing attention from researchers and practitioners as a way to merge together transport engineering and planning, land-use planning, and urban design for providing comprehensive solutions to contemporary urban problems. This attention has notably led to the publication of over 300 articles explicitly concerned with TOD in Web of Science journals, as well as to many implementations of the concept, some already completed and others underway (as, for example, the Grand Paris Project in France and Moscow Central Circle in Russia). Essentially, TOD can be described as land-use and transport planning that makes sustainable transport modes convenient and desirable, and that maximizes the efficiency of transport services by concentrating urban development around transit stations. However, as TOD projects started to be implemented worldwide, it became evident that their outcomes could be quite diverse, revealing that in practice the results of a project would depend on a wide variety of factors, trends and complex interrelations between them. In this article, we aim to provide a comprehensive, systematic and up-to-date review of TOD research achievements and challenges. We start by presenting the TOD concept, framing it in the theory of urban planning, and by describing the different typologies of TOD proposed in the literature. Then, we review the vast research dedicated to the study of TOD effects, distinguishing impacts on travel behavior, real-estate prices, residential location, urban form, and community life. The next subject we look at is TOD planning, focusing separately on policy issues and decision-support tools. In the final part of the article, based on the analysis of previous literature, we identify the main gaps and challenges that TOD research needs to address in the future.

In last three decades, very large investments were made in the transformation of the main road networks of Portugal and Spain. In contrast, during the same period, little has been done with regard to the secondary roads. In this paper, we present a study aimed at determining the best way of improving the secondary road network of the Centro Region of Portugal. This is one of the regions of the country where some accessibility problems persist. The study was made using a multi-objective road network planning model. In relation to the road network planning models available in the literature, the one we applied has a number of important, distinctive features. The objectives considered were efficiency (evaluated by four different measures: average travel speed; weighted travel cost; consumers' surplus gains; and weighted aggregate accessibility), equity (evaluated by the Gini Index), and energy (evaluated by fuel consumption). An overview of the measures used in the past to evaluate road network efficiency and a discussion of the implications of adopting the four efficiency measures considered are also provided. The results for the Centro Region of Portugal indicate that solutions can be significantly different when using each of the efficiency measures. As a conclusion of this study, a brief reflection about how to incorporate the perspectives, interests and budgets of different countries in a border network is presented.

Road network planning (or design) problems consist of determining the best investment decisions to be made with regard to the improvement of a road network. In this paper, we propose an optimization model for long-term interurban road network planning where accessibility and robustness objectives are simultaneously taken into account. Three network robustness measures were defined to assess different robustness concerns: network spare capacity; city evacuation capacity; and network vulnerability. The results that may be obtained from the application of the model are illustrated for three random networks. Special attention is given to the implications of adopting each one of the robustness measures upon the optimum solution provided by the model.

This article presents a multiobjective approach to long-term interurban multilevel road network planning. In addition to the efficiency objectives dealt with in most of the literature where the subject is addressed, the approach takes into account robustness and equity objectives. For achieving the objectives, two types of action can be performed: the construction of a new road of a given level; and the upgrading of an existing road to a higher level. The approach is consistent with the planning framework of the highway capacity manual, using the concept of level of service to assess traffic flow conditions. The application of the approach is illustrated for a case study involving the main road network of Poland.

The traditional approach to the road network design problem focuses on the optimization of network efficiency under a given budget. Generally, this leads to the improvement of roads next to the largest population centers, where travel demand is higher. Such results are not consistent with sustainable development principles, since the dissimilarities between the welfare of large and small centers will tend to increase. Nevertheless, equity issues were rarely taken into account in road network design. Moreover, all existing studies rely on a single equity measure. In this paper equity concerns in transportation planning are reviewed briefly, and a comparison of alternative equity measures is presented. Three equity measures were selected and incorporated into an accessibilitymaximization road network design model. The three equity measures reflect different perspectives on equity: accessibility to low-accessibility centers, the dispersion of accessibility values across all centers (Gini coefficient), and the dispersion of accessibility values across all centers and across centers in the same region (Theil index). The implications of adopting each of these equity measures are illustrated through application of the optimization model to three random networks.