Transportation Futures: Policy Scenarios for Achieving Greenhouse Gas Reduction Targets, MNTRC Report 12-11

It is well established that GHG emissions must be reduced by 50% to 80% by 2050 in order to limit global temperature increase to 2°C. Achieving reductions of this magnitude in the transportation sector is a challenge and requires a multitude of policies and technology options. The research presented here analyzes three scenarios: changes in the perceived price of travel, land-use intensification, and increases in transit. Elasticity estimates are derived using an activity-based travel model for the state of California and broadly representative of the U.S. The VISION model is used to forecast changes in technology and fuel options that are currently forecast to occur in the U.S., providing a life cycle GHG forecast for the road transportation sector. Results suggest that aggressive policy action is needed, especially pricing policies, but also more on the technology side. Medium- and heavy-duty vehicles are in particular need of additional fuel or technology-based GHG reductions

Congestion and Safety: A Spatial Analysis of London

Spatially disaggregate Enumeration District (ED) level data for London is used in an analysis of various area-wide factors on road casualties. Data on 15335 EDs was input into a geographic information system (GIS) that contained data on road characteristics, public transport accessibility, information of nearest hospital location, car ownership and road casualties. Demographic data for each ED was also included. Various count data models e.g., negative binomial or zero-inflated Poisson and negative binomial models were used to analyze the associations between these factors with traffic fatalities, serious injuries and slight injuries. Different levels of spatial aggregation were also examined to determine if this affected interpretation of the results. Different pedestrian casualties were also examined. Results suggest that dissimilar count models may have to be adopted for modeling different types of accidents based on the dependent variable. Results also suggest that EDs with more roundabouts are safer than EDs with more junctions. More motorways are found to be related to fewer pedestrian casualties but higher traffic casualties. Number of households with no car seems to have more traffic casualties. Distance of the nearest hospital from EDs tends to have no significant effect on casualties. In all cases, it is found that EDs with more employees are associated with fewer casualties.

The Impact of Transit-Oriented Development on Social Capital

This paper focuses on the ability of Transit Oriented Development (TOD) to improve social capital and interactions within a community. The expectation is that TOD has a positive impact on the lifestyle and activities of individuals who reside, work, and frequent these locations, and that this can include increases in social capital. Using data from a survey of transit station locations in New Jersey, the authors examine how proximity to the station and various built environment variables are associated with different measures of social capital, derived from responses to survey questions. These questions inquire about respondents’ perceptions of their neighborhood as a place to live, sense of community, knowing their neighbors, trust, and whether their community is a good place to raise a child. The authors also include a question on volunteering in the community. These questions reflect various domains of social capital as established in the literature. Results generally do not support the hypothesis that social capital is associated with transit station proximity and TOD. Features of the built environment, proxied by population and employment density, are also not associated with increased social capital, and in some cases have a negative association. While there are some limited positive associations with some of the social capital variables, one of the strongest indicators is living in a detached family home

An Analysis of the Spatio-Temporal Factors Affecting Aircraft Conflicts Based on Simulation Modelling

The demand for air travel worldwide continues to grow at a rapid rate, especially in Europe and the United States. In Europe, the demand exceeded predictions with a real annual growth of 7.1% in the period 1985-1990, against a prediction of 2.4%. By the year 2010, the demand is expected to double from the 1990 level. Within the UK international scheduled passenger traffic is predicted to increase, on average, by 5.8 per cent per year between 1999 and 2003. The demand has not been matched by availability of capacity. In Western Europe many of the largest airports suffer from runway capacity constraints. Europe also suffers from an en-route airspace capacity constraint, which is determined by the workload of the air traffic controllers, i.e. the physical and mental work that controllers must undertake to safely conduct air traffic under their jurisdiction through en-route airspace. The annual cost to Europe due to air traffic inefficiency and congestion in en-route airspace is estimated to be 5 billion US Dollars, primarily due to delays caused by non-optimal route structures and reduced productivity of controllers due to equipment inefficiencies. Therefore, to in order to decrease the total delay, an increase in en-route capacity is of paramount importance. At a global scale and in the early 1980s, the International Civil Aviation Organisation (ICAO) recognised that the traditional air traffic control (ATC) systems would not cope with the growth in demand for capacity. Consequently new technologies and procedures have been proposed to enable ATC to cope with this demand, e.g. satellite-based system concept to meet the future civil aviation requirements for communication, navigation and surveillance/ air traffic management (CNS/ATM). In Europe, the organisation EUROCONTROL (established in 1960 to co-ordinate European ATM) proposed a variety of measures to increase the capacity of en-route airspace. A key change envisaged is the increasing delegation of responsibilities for control to flight crew, by the use of airborne separation assurance between aircraft, leading eventually to ?free flight? airspace. However, there are major concerns regarding the safety of operations in ?free flight? airspace. The safety of such airspace can be investigated by analysing the factors that affect conflict occurrence, i.e. a loss of the prescribed separation between two aircraft in airspace. This paper analyses the factors affecting conflict occurrence in current airspace and future free flight airspace by using a simulation model of air traffic controller workload, the RAMS model. The paper begins with a literature review of the factors that affect conflict occurrence. This is followed by a description of the RAMS model and of its use in this analysis. The airspace simulated is the Mediterranean Free Flight region, and the major attributes of this region and of the traffic demand patterns are outlined next. In particular a day?s air traffic is simulated in the two airspace scenarios, and rules for conflict detection and resolution are carefully defined. The following section outlines the framework for analysing the output from the simulations, using negative binomial (NB) and generalised negative binomial (GNB) regression, and discusses the estimation methods required. The next section presents the results of the regression analysis, taking into account the spatio-temporal nature of the data. The following section presents an analysis of the spatial and temporal pattern of conflicts in the two airspace scenarios across a day, highlighting possible metrics to indicate this. The paper concludes with future research directions based upon this analysis.

Development and Application of an Activity Based Space-Time Accessibility Measure for Individual Activity Schedules

Accessibility is an important aspect of human existence impacting on our notion of society equity and justice. It plays an important role in a number of existing theories of spatial and travel behaviour in addition to affecting the rate and the pattern of land-use development. However despite the importance of the notion of accessibility, the accessibility measures, which have traditionally been used to quantify accessibility, have tended to be relatively poorly defined, excluding a wide range of observed forms of travel behaviour. This has ramifications for the implicit assumption underpinning the use of accessibility measures, namely that of a direct correlation between the measure of accessibility and individual travel behaviour. In this paper a hitherto unknown family of space-time route benefit measures are developed and utilised to derive an associated family of disaggregate activity based space-time utility accessibility measures. Applicable to individual activity schedules, these space-time activity accessibility measures implicitly acknowledge that travel is a derived demand. The paper commences with an outline of the limitations and primary assumptions present within traditional accessibility measures. The paper proceeds to provide a brief review of space-time user benefit measures highlighting their principle assumptions. Existing space-time locational benefit measures are subsequently extended to incorporate more realistic temporal constraints on activity participation and the perceived user benefit. The improved locational benefit measures incorporate a variety of factors including the utility an individual derives from activity participation, individual income, space-time constraints. In addition travel time, route delay and schedule disutility components such as the facility and activity wait times associated with early arrival are incorporated, in addition to late start time penalties associated with late commencement of an activity. The improved space-time locational benefit measure is subsequently applied to activity schedules incorporating a series of multiple linked activities. The paper subsequently demonstrates how the resulting user benefit measure can be shown to be part of a broader family of space-time route benefit measures, which despite their theoretical attractiveness have hitherto not been utilised by researchers. An associated family of space-time utility accessibility measures are subsequently developed and the paper proceeds to highlight how stochastic frontier models utilised in conjunction with existing travel/activity diary datasets can be utilised to operationalise the proposed measure of accessibility. The proposed family of accessibility measures are implemented within a point based spatial framework encompassing detailed spatially referenced land-use transportation network encompassing public transport, cycle, walk and car transport modes. Several practical examples are presented of the proposed family of accessibility measures in use and in particular demonstrate the strength and potential of the methodology in developing a wide range of transport-land-use policies. Examples are presented of the use of the methodology in developing new/improved transport links and services, the provision of additional land-use facilities/opportunities, extended opening of facilities/opportunities, the identification of transport related social exclusion, the development of equitable land-use transport schemes and policies as well as the development of flexible working policies. The paper concludes with a summary highlighting the principle benefits and properties of the proposed family of accessibility measures in addition to highlighting potential areas of future research.

Funding Resilient Infrastructure in New Jersey: Attitudes Following a Natural Disaster

Recent major natural disasters in New Jersey have demonstrated the need to increase the resilience of transportation infrastructure. This research examines public attitudes toward revenue sources that can be dedicated to protecting vulnerable areas, most notably the transportation linkages on which the state depends. A statewide survey was conducted to gather data approximately four months following Superstorm Sandy, the costliest natural disaster in the state’s history. The authors’ objective was to sample public attitudes while the impacts of the disaster were still fresh. They found little support for temporary tax increases to improve resiliency, with the most positive support for taxing visitors (i.e., a hotel and recreational tax) and for a 30-year bond measure (i.e., taxing the future). This observation seemingly contradicts broad support for investing in new infrastructure, as well as maintaining and protecting existing infrastructure. Multivariate analysis to understand the underlying attitudes toward raising revenue found that more left-leaning or communitarian attitudes are associated with more support for gasoline, income, or sales taxes devoted to mitigating vulnerability. Those who supported investment in transit and protecting infrastructure also were more likely to support these taxes. There was no parallel finding of factors associated with taxing visitors or issuing bonds

Increasing public transport provision in metropolitan areas can be of great benefit for wages and employment density

Increasing the provision of public transport is not only desirable in a time of concern over climate change and high fuel prices, it may also have important effects on employment and wages. Using current and historic data from over 360 U.S. metropolitan areas, Daniel G. Chatman and Robert B. Noland argue that public transport increases employment in central city areas, whilst also leading to higher wages in these areas totaling from between $1.5 million and$1.8 billion yearly depending on the city

From theory to practice in road safety policy: Understanding risk versus mobility

a b s t r a c t This paper reviews theoretical issues surrounding transport safety modeling and the implications for road safety policy. The behavioral mechanisms that affect transport safety are typically not considered in safety modeling. These issues are discussed in the context of trade-offs between risk-taking, as perceived by travelers, and other mobility objectives and the attributes associated with them. This is an extension of other theoretical frameworks, such as risk compensation, and attempts to integrate some of the previous frameworks developed over the years. Various examples of behavioral adaptation to specific policies are discussed and linked to the framework. These issues are then discussed in the context of improvements to empirical work in this area and the linkage of theoretical frameworks to crash modeling, in particular the estimation and use of Crash Modification Factors. Conclusions suggest that there are many deficiencies in practice, from estimation of models to choice of effective policies. Progress is being made on the former, while the publication of practical guidance seems to have substantial lags in knowledge

An analyses of pedestrian and bicycle casualties using regional panel data

An analysis is presented of pedestrian and bicycle casualties by using cross-sectional time series data for the regions of Great Britain. A fixed-effect negative binomial model is used that accounts for heterogeneity in the data and the distributional properties of count data. Various factors associated with those killed and seriously injured as well as with slight injuries are examined. These include the average age of vehicles in the region, the road length of various road classes, vehicle ownership in the region, per capita income, per capita expenditure on alcohol, age cohorts, and various proxies for medical technology improvements. Various specifications of the models are estimated. Generally, it is found that more serious pedestrian injuries are associated with lower-income areas, increases in percent of local roads, increased per capita expenditure on alcohol, and total population. Statistical effects are more difficult to detect in models with serious injuries for bicyclists, but alcohol expenditure is strongly associated with increased injuries. This work has implications for transport policy aimed at increasing the modal share of pedestrians and bicyclists. Further research is needed to clearly understand some of the trends found in the analysis, especially the effect of changes in medical care and technology on total injuries

Congestion and safety: a spatial analysis of London

A disaggregate spatial analysis, using enumeration district data for London was conducted with the aim of examining how congestion may affect traffic safety. It has been hypothesized that while congested traffic conditions may increase the number of vehicle crashes and interactions, their severity is normally lower than crashes under uncongested free flowing conditions. This is primarily due to the slower speeds of vehicles when congestion is present. Our analysis uses negative binomial count models to examine whether factors affecting casualties (fatalities, serious injuries and slight injuries) differed during congested time periods as opposed to uncongested time periods. We also controlled for congestion spatially using a number of proxy variables and estimated pedestrian casualty models since a large proportion of London casualties are pedestrians. Results are not conclusive. Our results suggest that road infrastructure effects may interact with congestion levels such that in London any spatial differences are largely mitigated. Some small differences are seen between the models for congested versus uncongested time periods, but no conclusive trends can be found. Our results lead us to suspect that congestion as a mitigator of crash severity is less likely to occur in urban conditions, but may still be a factor on higher speed roads and motorways