Greg Marsden

Towards an understanding of adaptive cruise control

Adaptive cruise control (ACC) provides assistance to the driver in the task of longitudinal control of their vehicle during motorway driving. The system controls the accelerator, engine powertrain and vehicle brakes to maintain a desired time-gap to the vehicle ahead. This research describes the results of a detailed microscopic simulation investigation into the potential impacts of ACC on motorway driving. In addition to simulation, real vehicle driving profiles, obtained from instrumented vehicle experiments in three European countries, have been used to compare real following behaviour with that of a simulated ACC equipped vehicle. This new approach has shown that following with an ACC system can provide considerable reductions in the variation of acceleration compared to manual driving. This indicates a potential comfort gain for the driver and environmental benefits. A number of critical situations in which ACC does not perform well have also been identified. The research also highlights the limitations of microscopic simulation in modelling the impacts of ACC because of the lack of understanding of the interaction between the driver and the ACC system relative to the traffic conditions.

Bounded rationality in policy learning amongst cities: lessons from the transport sector

The internationalization of policy regimes and the reorganization of the state have provided new opportunities for cities to bypass nation-state structures and work with other cities internationally. This provides greater opportunity for cities to learn from each other and could be an important stimulus to the transfer of policies across the globe. Few studies exist however which focus on the processes that shape the search for policy lessons and how they are affected by the institutional context within which they are conducted. This paper describes research conducted in the field of urban transport and planning policy across eleven cities in Northern Europe and North America which seeks to explore the motivations for and mechanisms supporting learning about new policies. Thirty policies were examined across the eleven sites using document review and interviews with key actors. The paper explores the search for lessons and the learning process and considers the influences of institutional context, organizational behaviour, and individual cognitive constraints. The process of seeking out and learning policy lessons is defined by individuals operating within a particular policy space and exhibits a number of characteristics of strongly bounded rational choice. The search parameters are significantly influenced by preconceptions of the nature of the preferred solutions and the likelihood of cities in other contexts offering meaningful learning opportunities. Trusted peer networks emerge as critical in overcoming information overload, resource constraints, and uncertainty in the potential for policy transfer. The mobility of policies seems also to be linked to the mobility of the key transfer agents. Cities adopt quite different approaches to engaging with the communities of policy mobilizers which seems likely to impact on the pace and pattern of the movement of policies.

Do institutional arrangements make a difference to transport policy and implementation? Lessons for Britain

The authors describe local government decisionmaking in transport in three areas of the United Kingdom—London, West Yorkshire, and Edinburgh—in which major changes in local government decisionmaking structures have taken place over the last decade, and between which arrangements are now very different. They discuss whether institutional change has had a beneficial or adverse effect, and whether any of the current structures provides a more effective framework for policy development and implementation. The results suggest that, although the sites share a broadly common set of objectives, there are differences in devolved responsibilities and in the extent to which various policy options are within the control of the bodies charged with transport policy delivery. The existence of several tiers of government, coupled with the many interactions required between these public sector bodies and the predominantly private sector public transport operators, appears to create extra transactional barriers and impedes the implementation of the most effective measures for cutting congestion. There is, however, a compelling argument for the presence of an overarching tier of government to organise travel over a spatial scale compatible with that of major commuter patterns. The extent to which such arrangements currently appear to work is a function of the range of powers and the funding levels afforded to the coordinating organisation.

Sustainability Assessment: The Definition Deficit

ABSTRACT Much work has focused on the development of indicator sets to monitor changes in the sustainability of transport. Such indicator sets are however, often quite divorced from those used in decision-making and fail to include clear sustainability goals to work towards. This research describes the development of a sustainability appraisal framework in conjunction with a series of key decision-makers in England. A case study of a real set of strategy options tested in a metropolitan area is outlined and the results used to assess the extent to which current strategy development in the United Kingdom produces the information required to both assess and communicate progress towards sustainability. The results suggest that although sustainability exists as a concept, it is poorly defined. This definition deficit has serious implications for the types of strategies tested. First, information on some aspects of sustainability is not produced and so these aspects are marginalized. Secondly, the lack of policy goals and the dominant welfare economics assessment paradigm allow unsustainable strategies to be justified provided they perform better than an unsustainable ‘do-minimum’. The paper concludes with some recommendations for the policy and research communities to bridge the current gap in thinking.

TOWARDS A REAL-TIME MICROSCOPIC EMISSIONS MODEL

Abstract This article presents a new approach to microscopic road traffic exhaust emission modelling. The model described uses data from the SCOOT demand-responsive traffic control system implemented in over 170 cities across the world. Estimates of vehicle speed and classification are made using data from inductive detector loops located on every SCOOT link. This data feeds into a microscopic traffic model to enable enhanced modelling of the driving modes of vehicles (acceleration, deceleration, idling and cruising). Estimates of carbon monoxide emissions are made by applying emission factors from an extensive literature review. A critical appraisal of the development and validation of the model is given before the model is applied to a study of the impact of high emitting vehicles. The article concludes with a discussion of the requirements for the future development and benefits of the application of such a model.

Blame Games and Climate Change: Accountability, Multi-Level Governance and Carbon Management

Research Highlights and Abstract This article provides the first detailed and evidence-based account of the coalition governments approach to transport-related carbon management. It exposes the existence of a ‘governance vacuum’ between the statutory target and a very weak devolved implementation system (i.e. ‘fuzzy governance’ and ‘fuzzy accountability’). Research in four major city regions reveals a systemic switch from an emphasis on carbon management and reduction towards economic growth and job creation. Officials within the policy design and delivery chain emphasise the manner in which the demands of democratic politics tend to frustrate meaningful policy change. A general demand by actors at the local level not for the discretions delivered by localism but for a more robust and centrally managed—even statutory—governance framework. The Climate Change Act 2008 received global acclaim for embedding an ambitious set of targets for the reduction of carbon emissions in legislation. This article explores the policies and institutional frameworks in place to deliver transport-related carbon reductions as part of the subsequent Carbon Plan. A detailed methodology involving institutional mapping, interviews and focus groups combined with a theoretical approach that combines the theory of multi-level governance with the literature on ‘blame avoidance’ serves to reveal a complex system of ‘fuzzy governance’ and ‘fuzzy accountability’. Put simply, it reveals there are no practical sub-national implementation levers for achieving the statutory targets. Apart from symbolic or rhetorical commitments, the emphasis of policy-makers at all levels in the delivery chain has switched from carbon management and reduction to economic growth and job creation. This raises fresh research questions about the pathologies of democratic competition and future responses to the climate change challenge.

Muddling through with climate change targets: a multi-level governance perspective on the transport sector

The UK Climate Change Act 2008 commits to a reduction of 80% in national GHG emissions by 2050 compared to 1990 levels. This article explores what happens next where these top-level aspirations are expected to be turned into radical action. It does so through examination of the transport sector, which is a highly complex, fragmented, and multi-level delivery environment. The research draws on cases studies of four major cities with different governance structures within the two distinct, yet connected, national contexts of England and Scotland. It integrates a range of theoretical legacies, namely ‘muddling through’, multi-level governance, and positional analysis, to look across governmental layers and out to non-governmental actors at all levels. Underneath the 80% target, the framework for action remains unclear. Lower-tiered authorities report difficulties in acting in a more comprehensive or rapid manner than upper tiers of government, largely because of the potential costs involved and a significant resource dependency on national governments. Ambition is also tempered by conflicts with economic growth objectives and the difficulties in aligning the objectives of the myriad of public and private organizations that need to take action.

Assessment of Capabilities for Examining Long-Term Social Sustainability of Transport and Land Use Strategies

The development of transport and land use strategies tends to rely, to a large degree, on inputs from large strategic models. Although it is commonplace for such models to assess the economic and environmental impacts of transport strategies, few provide any real understanding of their social impacts. This paper reports on a study that aims to improve how the social sustainability of transport strategies is considered. The study is part of a wider project conducted to improve the ability to assess the overall sustainability of transport decisions. It describes the four-stage method that was adopted. The approach is pioneering, focusing as it does on accessibility to key services and facilities as a primary measure of social sustainability. Nevertheless, the approach has a number of serious limitations in both selecting indicators and applying them in practice. It is also clear from the experiences with adapting the outputs of state-of-the-art models that the technical capacity for assessing the social implications of transport continues to fall well short of the technical capacity for assessing the economic and environmental impacts of strategies. A series of recommendations to improve the technical capacity in this respect is provided.

Determinants of travel demand--exploring the future of society and lifestyles in the UK

This paper considers how changes in the fabric of society and its values, a subject usually considered to be outside the conventional scope of the transport profession, can have a profound impact on travel demand. The paper stems from the Transport Visions Network, a unique activity involving young professionals from academia, consultancy and government. It raises awareness of the diversity of factors that influence travel and transport. The paper offers an overview of existing trends and projections for the future before presenting a series of different future scenarios. Suggestions on the consequences for transport are then put forward.

Framework for Sustainability Assessment by Transportation Agencies

The application of the concept of sustainability by transportation agencies is often limited by agencies’ understanding of what sustainability means and how it can be integrated into the regular functions of the agencies. This paper presents a flexible approach and framework that can equip transportation agencies with the tools required to understand what sustainability means and incorporate sustainability into the organizational culture. This approach and method can also help agencies lay the groundwork for the use of performance measures so the agencies can progress toward sustainability goals and outcomes. The framework development process was an extension of findings from literature review, case studies, and interviews conducted as part of ongoing research under the NCHRP project Sustainability Performance Measures for State Departments of Transportation and Other Transportation Agencies. The proposed framework can be applied or adapted for use in a range of transportation agencies, including state departments of transportation and metropolitan planning organizations. A key feature of this framework is that it moves away from the traditional sustainable transportation perspective and instead promotes the consideration of transportation from a holistic sustainable development perspective. The framework defines broadly applicable transportation goals that can be broken down into a menu of objectives and performance measures to cover various transportation contexts. The framework is also designed to direct an agencys strategic planning toward the practical implementation of sustainability through performance measurement.