A multi-instrumented approach to observing the activity rescheduling decision process

Activity scheduling simulation models represent an emerging and proposing approach to forecasting travel demand. The most significant developmental challenge is the lack of empirical data on how people actually proceed through the scheduling and conflict resolution process. This paper develops a new methodology to collect data about the rescheduling decision process. The data collection involves six stages: preplanned schedule interview, coding of the preplanned schedule, second-by-second Global Positioning System tracking, internet-based prompted recall diary, detection of rescheduling decisions (via comparison of planned versus executed activities), and a final in-depth interview probing the how and why of rescheduling decisions. Each stage of the methodology is described in detail with example results drawn from a pilot study. Key discoveries include: elicitation of multiple preplanned schedule reporting methods (verbal, point-form, calendar); discovery that activity attributes (time, location, involved persons) are planned on significantly different time horizons and include partial elaboration; and provision of new insights into how and why rescheduling decisions are made. A method for automatically tracking rescheduling decisions was also discovered. Overall, the new methodology has potential to contribute to the development of more realistic models of the entire scheduling process, especially rescheduling and conflict resolution sub-models.     

The effect of neighbourhood characteristics,accessibility, home–work location,and demographics on commuting distances

The goal of this paper is to better understand home-to-work travel distances throughout the Montréal Metropolitan region. A simultaneous equation modelling analysis is carried out to jointly explain commuter trip length and home–work location as a function of neighbourhood typologies, commuter socio-demographics and measures of job and worker accessibility. First, a factor and cluster analysis of urban form is performed over the entire region on a fine-scale grid pattern. The outcome of this analysis is the classification of typologies at both home and job locations. Different measures of accessibility and commuter socio-demographics are then incorporated into the analysis. Varied data sources including a detailed Montréal Origin–Destination Survey on over 30,000 home-to-work automobile trips are analyzed. Among other results, commuters that live and work in a different sub-region almost double the average trip distance and although socio-economic factors have a statistically significant correlation with commuter distance, these factors have a marginal effect. Interestingly, our results highlight the importance of urban form and job accessibility. Deciding on whether to live and work in the same sub-region was modelled as an endogenous binary random utility model; unobserved heterogeneities seem to be simultaneously influencing both the home–work location choice and trip-to-work distances. Our results underscore the importance of home–work location with respect to urban form and job accessibility. Hence, policies that support more dense and mixed land-use in suburban areas would not be enough to reduce commuter distances. These actions should be accompanied by other policy initiatives to discourage long car trips.     

Optimization models to characterize the broadcast capacity of vehicular ad hoc networks

Broadcast capacity of the entire network is one of the fundamental properties of vehicular ad hoc networks (VANETs). It measures how efficiently the information can be transmitted in the network and usually it is limited by the interference between the concurrent transmissions in the physical layer of the network. This study defines the broadcast capacity of vehicular ad hoc network as the maximum successful concurrent transmissions. In other words, we measure the maximum number of packets which can be transmitted in a VANET simultaneously, which characterizes how fast a new message such as a traffic incident can be transmitted in a VANET. Integer programming (IP) models are first developed to explore the maximum number of successful receiving nodes as well as the maximum number of transmitting nodes in a VANET. The models embed an traffic flow model in the optimization problem. Since IP model cannot be efficiently solved as the network size increases, this study develops a statistical model to predict the network capacity based on the significant parameters in the transportation and communication networks. MITSIMLab is used to generate the necessary traffic flow data. Response surface method and linear regression technologies are applied to build the statistical models. Thus, this paper brings together an array of tools to solve the broadcast capacity problem in VANETs. The proposed methodology provides an efficient approach to estimate the performance of a VANET in real-time, which will impact the efficacy of travel decision making.     

A model to identify airport hubs and their importance to tourism in Brazil

Air transportation in Brazil has been recently liberalized and one of the consequences of this process is the concentration of flights in a few hubs. During the years 2006-2007 two fatal accidents created unprecedented chaos in both land and air sides of the system with harmful consequences to tourism in Brazil. The consequences were more airport congestion and many episodes of flight delays and cancellations that lasted for several months. We argue that, among other factors, this state of blackout was a result of the increase in the degree of concentration in few airports, particularly Congonhas (in São Paulo) and Brasília. Using data obtained from a survey with Brazilian experts, a comparison was made with two existing methods (the one used by the US Federal Aviation Administration and the usual Herfindahl-Hirschman method) in order to calculate the number of hubs in Brazil. Due to the huge discrepancy obtained between data from the survey and the other two methods considered, a new mathematical method based on the Herfindahl-Hirschman Index was proposed to identify the number of hubs in a given network. Drawing from the examples of what happened to tourist destinations during and after the air transport crisis in Brazil, the article concludes discussing the need for a more accurate tool to identify and to monitor the concentration of flights at the Brazilian air transportation network and its importance to tourism.     

The acceptability of road pricing in Vienna: the preference patterns of car drivers

The acceptability of road pricing has attracted considerable attention among researchers over the last decade, as is evident in the amount of literature about transport and environmental economics. The general conclusion from these studies has been that there is low acceptability for road pricing among car users. In this paper, we add more knowledge to the existing literature by conducting an acceptability study of road pricing in Vienna, where such a study has never been conducted before. We used a replication study approach where a previous approach used in the EU research project AFFORD (acceptability of fiscal and financial measures and organisational requirements for demand management) was replicated for Vienna and further supplemented with a conjoint analysis. In order to examining whether the Vienna study confirms previous findings. We investigated the acceptability of two concrete policy packages factors influencing this acceptability, and preference patterns that can be used in designing a road pricing policy for Vienna. The survey reveals a higher acceptability if road pricing schemes lead to perceived personal benefits. According to the multivariate analyses, the “personal outcome expectations”, “social norm” and “perceived effectiveness” variables account for more than 50 % of the criterion variance and therefore these are the most influential factors. Road pricing schemes can be an effective transport management instrument for a city particularly if they are associated with direct investment in public transport and public infrastructure. Thus, personal benefits can be perceived more easily and direct effects can be expected.     

Real-time vision-based blind spot warning system: Experiments with motorcycles in daytime/nighttime conditions

This paper describes a real-time vision-based blind spot warning system that has been specially designed for motorcycles detection in both daytime and nighttime conditions. Motorcycles are fast moving and small vehicles that frequently remain unseen to other drivers, mainly in the blind-spot area. In fact, although in recent years the number of fatal accidents has decreased overall, motorcycle accidents have increased by 20%. The risks are primarily linked to the inner characteristics of this mode of travel: motorcycles are fast moving vehicles, light, unstable and fragile. These features make the motorcycle detection problem a difficult but challenging task to be solved from the computer vision point of view. In this paper we present a daytime and nighttime vision-based motorcycle and car detection system in the blind spot area using a single camera installed on the side mirror. On the one hand, daytime vehicle detection is carried out using optical flow features and Support Vector Machine-based (SVM) classification. On the other hand, nighttime vehicle detection is based on head lights detection. The proposed system warns the driver about the presence of vehicles in the blind area, including information about the position and the type of vehicle. Extensive experiments have been carried out in 172 minutes of sequences recorded in real traffic scenarios in both daytime and nighttime conditions, in the context of the Valencia MotoGP Grand Prix 2009.     

Integrating Climate and Ocean Change Vulnerability into Conservation Planning

Tropical coastal and marine ecosystems are particularly vulnerable to ocean warming, ocean acidification, and sea-level rise. Yet these projected climate and ocean change impacts are rarely considered in conservation planning due to the lack of guidance on how existing climate and ocean change models, tools, and data can be applied. Here, we address this gap by describing how conservation planning can use available tools and data for assessing the vulnerability of tropical marine ecosystems to key climate threats. Additionally, we identify limitations of existing tools and provide recommendations for future research to improve integration of climate and ocean change information and conservation planning. Such information is critical for developing a conservation response that adequately protects these ecosystems and dependent coastal communities in the face of climate and ocean change.     

Environmental quality within an interorganizational matrix: A case study of the SOHIO project

Abstract

Urban coastal management is now part of a large, complex set of regional, state, and federal interorganizational arrangements. This emerging matrix consists of a loosely linked set of nearly independent decision points. Cities have little capacity within this matrix for independent action. Recent experience in the SOHIO project by the City and Port of Long Beach, California, illustrates the point to which external agencies have taken over decision‐making for use of coastal resources. Public bodies removed from city affairs and politics and with interests in other than coastal affairs have become dominant and have overridden local policy‐making. The public costs to citizens and local governments of the emerging interorganizational matrix are very high and may be excessive. As it is emerging, the matrix is a semi‐autonomous set of bureaucratic decision points which is unhinged from community values and regular political infrastructures.     

Maritime investment strategies with a portfolio of real options

The maritime industry operates in a dynamic global environment subject to a great number of variables. In this context, the investment challenge facing shipowners is correctly to value alternate mutually exclusive investment strategies before proceeding with confidence to commit to a project which will add the greatest value to the firm. To survive in the competitive market environment shipping companies must be flexible. Companies that rely solely on traditional discounted cash flow analysis may be underestimating the true value of their investment by not valuing any embedded real options specifically. To avoid misallocation of resources, the true value of these embedded options (strategies) should be recognised and quantified where possible for inclusion in the capital budgeting process. Using real options analysis, (ROA), as a development of the financial pricing advances of the 1970s, flexibility is valued like a financial option using non-arbitrage and added to the present value of the original strategy to derive the present value of the flexible strategy. The more uncertainty (risk) present, the greater will be the value of the real options. Similarly, the larger the shipowner's portfolio of options (strategies) from which to choose, the greater will be the valuation of the project. Real options give the shipowner the flexibility to exchange one risky income stream associated with one strategy for that of another. The analysis shows that if managers have the flexibility of more than one embedded option (in this paper, a European put associated with a replacement investment and an option on the maximum of two operating strategies, trading or chartering out) then the project will have greater value than if the there was no choice or if it was limited to one or the other strategy. Sensitivity analysis extends the analysis to demonstrate that if the volatilities of the risky income streams are highly correlated then the additional value of this flexibility will diminish.     

Surveillance and Poaching on Inshore Reefs of the Great Barrier Reef Marine Park

The Great Barrier Reef (GBR), Australia, is managed under the GBR Marine Park Act (1975) and is seen as a shining example of marine resource management. The principle tool of management is zoning for multiple use. We examined surveillance and illegal fishing around two inshore islands (Magnetic and Orpheus) of the GBR Marine Park in 2000/2001. Both islands are near Townsville, the largest city adjacent to the GBR. Surveillance effort was low, with vessels present on only 16% of days of the year. Measurable but low levels of illegal recreational fishing occurred within no-take zones. Levels decreased with increasing surveillance effort. Thus zoning was not completely successful in protecting fish targeted by fisheries, even within the most highly enforced sections of the Park. The expansion of no-take zones in 2004 from 4.6% to 33.4% of the area of the 358,000 km2 Park represents a considerable challenge for future surveillance and enforcement.