Imperial College London

Professor Dan Graham

Faculty of EngineeringDepartment of Civil and Environmental Engineering

Professor of Statistical Modelling
 
 
 
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Contact

 

+44 (0)20 7594 6088d.j.graham Website

 
 
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Location

 

611Skempton BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

127 results found

Achurra Gonzalez PE, Angeloudis P, Hu S, Zavitsas K, Graham DJet al., Modelling the impact of infrastructure developments on the resilience of intermodal container transport networks: One-Belt-One-Road Case study, 7th International Conference on Logistics and Maritime Systems

CONFERENCE PAPER

Achurra Gonzalez PE, Angeloudis P, Zavitsas K, Niknejad SA, Graham DJet al., A Quantitative Framework for Assessment of Network Vulnerability in Liner Shipping Networks, Transportation Research Board 96th Annual Meeting

CONFERENCE PAPER

Achurra Gonzalez PE, Angeloudis P, Zavitsas K, Niknejad SA, Graham DJet al., Attacker-defender modelling of transport vulnerability in maritime logistics corridors, 2nd International Workshop on Maritime Flows and Networks

CONFERENCE PAPER

Anderson RJ, Brage-Ardao R, Graham DJ, barron Aet al., Econometric Benchmarking of Metro Operating Costs. Methods and Applications, European Transport Conference 2015

CONFERENCE PAPER

Cohen JM, Barron A, Anderson R, Graham Det al., Increased likelihood of injury as a form of transport disadvantage for differently abled and elderly travellers: Evidence from urban metro subway systems, 14th International Conference on Mobility and Transport for Elderly and Disabled Persons

CONFERENCE PAPER

Graham DJ, Agglomeration Economies and Transport Investment

This paper is concerned with the links between agglomeration, productivity and transport investment. If improvements in transport systems give rise to changes in the mass of economic activity accessible to firms, for instance by reducing travel times or the costs of travel, then they can induce positive benefits via agglomeration economies. The paper presents empirical results from an econometric analysis of the relationship between productivity and accessibility to economic activity for different sectors of the UK economy. The results show that agglomeration economies do exist and that they can be substantial, particularly for services. Furthermore, the effect of agglomeration externalities is not trivial when considered in the context of transport appraisal. Initial calculations typically indicate additions to conventional user benefits of 10%-20% arising from increasing returns to economic mass.

SCHOLARLY EDITION

Horcher D, Graham DJ, The dark side of travel passes: Wrong incentive in crowding, Transportation Research Board 95th Annual Meeting, Washington D.C.

CONFERENCE PAPER

Horcher D, Graham DJ, Crowding and the marginal cost of travelling under second-best capacity provision, International Transport Economics Association Annual Conference

The classic economic theory of capacity optimisation in public transport suggests that the welfare maximising frequency and vehicle size increase with demand, and therefore the optimal occupancy rate may not dependent on demand; crowding can be internalised through capacity adjustment. On the other hand, empirical studies show that the crowding externality does contribute significantly to the social cost of public transport usage in large metropolitan areas. This paper presents a theoretical framework that explains why rational second-best capacity provision may lead to a wide range of demand dependent crowding levels under economies of vehicle size, infrastructure constraints and demand fluctuations. We derive the marginal external waiting time, crowding and operational costs of travelling for second-best scenarios, and explore the resulting subsidy rates. Thus, we take an important step towards the full understanding of optimal demand and crowding dependent pricing in public transport.

CONFERENCE PAPER

Horcher D, Graham DJ, Anderson R, The link between crowding pricing and seat supply in public transport, Transportation Research Board 95th Annual Meeting, Washington D.C.

CONFERENCE PAPER

Horcher D, Graham DJ, Anderson RJ, The economic inefficiency of travel passes under crowding externalities and endogenous capacity, Journal of Transport Economics and Policy, ISSN: 0022-5258

JOURNAL ARTICLE

Maré D, Graham DJ, Agglomeration Elasticities in New Zealand

This paper analyses the relationship between firms’ multi-factor productivity and the effective employment density of the areas where they operate. Quantifying these agglomeration elasticities is of central importance in the evaluation of the wider economic benefits of transport investments. We estimate agglomeration elasticities using the Statistics New Zealand prototype Longitudinal Business Database: a firm-level panel covering the period 1999 to 2006. We estimate that an area with 10 percent higher effective density has firms with productivity that is 0.69 percent higher, once we control for the industry specific production functions and sorting of more productive firms across industries and locations. We present separate estimates of agglomeration elasticities for specific industries and regions, and examine the interaction of agglomeration with capital, labour, and other inputs.

SCHOLARLY EDITION

Achurra Gonzalez PE, Angeloudis P, Zavitsas K, Niknejad, Graham Det al., 2017, Attacker-defender assessment of vulnerability in maritime logistics corridors, Advances in Shipping Data Analysis and Modeling. Tracking and Mapping Maritime Flows in the Age of Big Data, Editors: Ducruet, Publisher: Routledge

BOOK CHAPTER

Hoercher D, Graham DJ, Anderson RJ, 2017, Crowding cost estimation with large scale smart card and vehicle location data, TRANSPORTATION RESEARCH PART B-METHODOLOGICAL, Vol: 95, Pages: 105-125, ISSN: 0191-2615

JOURNAL ARTICLE

Li H, Graham DJ, Liu P, 2017, Safety effects of the London cycle superhighways on cycle collisions, ACCIDENT ANALYSIS AND PREVENTION, Vol: 99, Pages: 90-101, ISSN: 0001-4575

JOURNAL ARTICLE

Melo PC, Graham DJ, Levinson D, Aarabi Set al., 2017, Agglomeration, accessibility and productivity: Evidence for large metropolitan areas in the US, URBAN STUDIES, Vol: 54, Pages: 179-195, ISSN: 0042-0980

JOURNAL ARTICLE

Mohammad SI, Graham DJ, Melo PC, 2017, The effect of the Dubai Metro on the value of residential and commercial properties, JOURNAL OF TRANSPORT AND LAND USE, Vol: 10, Pages: 263-290, ISSN: 1938-7849

JOURNAL ARTICLE

Morse L, Trompet M, Barron A, Graham DJet al., 2017, Development of a key performance indicator system to benchmark relative paratransit performance, Transportation Research Record, Vol: 2650, Pages: 1-8, ISSN: 0361-1981

The Americans with Disabilities Act of 1990 prohibits discrimination against people with disabilities. U.S. transit agencies are therefore required to offer eligible customers services that complement the mobility opportunities provided to the general public on fixed-route public transit. Although these paratransit services are necessary and just, they represent a proportionally large cost to agencies: approximately eight times the cost per boarding compared with fixed-route bus service. To be able to identify opportunities for cost efficiencies and to further improve the quality of paratransit services offered, the 20 agencies of the American Bus Benchmarking Group decided to benchmark their relative performance in paratransit management and operations. A key performance indicator system was developed, and associated data items were defined in detail to ensure comparability of agencies' performance and hence ensure the usefulness of the benchmarking program. The scope of this system went beyond the data already provided to the National Transit Database, both in amount and in granularity of data collected as well as the detail of definitions. The challenges, respective solutions, and other lessons identified during 4 years of paratransit benchmarking development led by Imperial College London, the American Bus Benchmarking Group facilitators, are described. The paper provides transit agencies and authorities as well as benchmarking practitioners and academics an opportunity to apply these lessons for the further benefit of paratransit services and their customers around the United States.

JOURNAL ARTICLE

Mundy D, Trompet M, Cohen J, Graham Det al., 2017, The Identification and Management of Bus Priority Schemes; A Study of International Experiences and Best Practices

Priority measures for bus services can deliver significant benefits both for passengers and the operator. For example, green light priority or the conversion of road space to dedicated bus lanes can deliver journey time (variability/predictability) benefits thereby improving both quality of service and operational efficiency. This study investigates how bus priority schemes are identified, selected and managed in 14 different cities across Asia, Australia, Europe and North America. The study reviews the decision making processes, including associated input from bus operators, involved in identifying necessary bus schemes. The study provides examples of succesful and unsuccessful bus priority schemes and methods of bus priority enforcement are explored to establish interesting and successful ways to ensure bus priority measures can be effective. This report may be useful to different stakeholders experiencing difficulties with bus priority selection, implementation and management, such as city/ borough governments, road authorities, bus operators, passenger groups, police, and other organisations.

REPORT

Achurra-Gonzalez PE, Novati M, Foulser-Piggott R, Graham DJ, Bowman G, Bell MGH, Angeloudis Pet al., 2016, Modelling the impact of liner shipping network perturbations on container cargo routing: Southeast Asia to Europe application., Accid Anal Prev

Understanding how container routing stands to be impacted by different scenarios of liner shipping network perturbations such as natural disasters or new major infrastructure developments is of key importance for decision-making in the liner shipping industry. The variety of actors and processes within modern supply chains and the complexity of their relationships have previously led to the development of simulation-based models, whose application has been largely compromised by their dependency on extensive and often confidential sets of data. This study proposes the application of optimisation techniques less dependent on complex data sets in order to develop a quantitative framework to assess the impacts of disruptive events on liner shipping networks. We provide a categorization of liner network perturbations, differentiating between systemic and external and formulate a container assignment model that minimises routing costs extending previous implementations to allow feasible solutions when routing capacity is reduced below transport demand. We develop a base case network for the Southeast Asia to Europe liner shipping trade and review of accidents related to port disruptions for two scenarios of seismic and political conflict hazards. Numerical results identify alternative routing paths and costs in the aftermath of port disruptions scenarios and suggest higher vulnerability of intra-regional connectivity.

JOURNAL ARTICLE

Brage-Ardao R, Graham DJ, Anderson RJ, 2016, Determinants of rolling stock maintenance cost in metros, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART F-JOURNAL OF RAIL AND RAPID TRANSIT, Vol: 230, Pages: 1487-1495, ISSN: 0954-4097

JOURNAL ARTICLE

Horcher D, Graham DJ, Anderson RJ, 2016, Merging smart card data and train movement data: How to assign trips to trains?, Merging smart card data and train movement data: How to assign trips to trains?

This report explains the assignment method applied to link trips compiled in smart card data to train movements recorded in the signalling system. Particular attention has been paid to (1) origin-destination pairs with multiple potential route options, (2) peak-hour trips delayed by di culties in boarding crowded trains at the origin station, and (3) trips originating or ending on rail lines not included in the train movement dataset.In the current version of this paper the metro network on which the method has been applied is anonymised.

REPORT

Li H, Graham DJ, 2016, Quantifying the causal effects of 20 mph zones on road casualties in London via doubly robust estimation, ACCIDENT ANALYSIS AND PREVENTION, Vol: 93, Pages: 65-74, ISSN: 0001-4575

JOURNAL ARTICLE

Li H, Graham DJ, 2016, Heterogeneous treatment effects of speed cameras on road safety, ACCIDENT ANALYSIS AND PREVENTION, Vol: 97, Pages: 153-161, ISSN: 0001-4575

JOURNAL ARTICLE

Yannis G, Dragomanovits A, Laiou A, Richter T, Ruhl S, La Torre F, Domenichini L, Graham D, Karathodorou N, Li Het al., 2016, Use of Accident Prediction Models in Road Safety Management – An International Inquiry, Transportation Research Procedia, Vol: 14, Pages: 4257-4266, ISSN: 2352-1465

JOURNAL ARTICLE

Brage-Ardao R, Graham DJ, Anderson RJ, 2015, Determinants of Train Service Costs in Metro Operations, TRANSPORTATION RESEARCH RECORD, Pages: 31-37, ISSN: 0361-1981

JOURNAL ARTICLE

Canavan S, Graham DJ, Melo PC, Anderson RJ, Barron AS, Cohen JMet al., 2015, Impacts of Moving-Block Signaling on Technical Efficiency Application of Propensity Score Matching on Urban Metro Rail Systems, TRANSPORTATION RESEARCH RECORD, Pages: 68-74, ISSN: 0361-1981

JOURNAL ARTICLE

Cohen JM, Barron AS, Anderson RJ, Graham DJet al., 2015, Impacts of Unattended Train Operations on Productivity and Efficiency in Metropolitan Railways, TRANSPORTATION RESEARCH RECORD, Pages: 75-83, ISSN: 0361-1981

JOURNAL ARTICLE

Graham DJ, McCoy EJ, Stephens DA, 2015, Approximate Bayesian Inference for Doubly Robust Estimation, Bayesian Analysis, Vol: 11, Pages: 47-69, ISSN: 1936-0975

Doubly robust estimators are typically constructed by combining outcomeregression and propensity score models to satisfy moment restrictions thatensure consistent estimation of causal quantities provided at least one of the componentmodels is correctly specified. Standard Bayesian methods are difficult toapply because restricted moment models do not imply fully specified likelihoodfunctions. This paper proposes a Bayesian bootstrap approach to derive approximateposterior predictive distributions that are doubly robust for estimation ofcausal quantities. Simulations show that the approach performs well under varioussources of misspecification of the outcome regression or propensity score models.The estimator is applied in a case study of the effect of area deprivation on theincidence of child pedestrian casualties in British cities.

JOURNAL ARTICLE

Graham DJ, McCoy EJ, Stephens DA, 2014, Quantifying Causal Effects of Road Network Capacity Expansions on Traffic Volume and Density via a Mixed Model Propensity Score Estimator, JOURNAL OF THE AMERICAN STATISTICAL ASSOCIATION, Vol: 109, Pages: 1440-1449, ISSN: 0162-1459

JOURNAL ARTICLE

Li H, Graham DJ, Majumdar A, 2014, Effects of changes in road network characteristics on road casualties: An application of full Bayes models using panel data, Safety Science, Vol: 72, Pages: 283-292, ISSN: 0925-7535

In order to ensure a high level of road safety, road network planning needs to be based on the best knowledge available of the effects of road design on road safety. In this study, we look into how changes in road network characteristics affect road casualties. An approach based on traffic assignment is proposed in order to estimate the traffic exposure at ward level. We apply a widely used approach for before–after evaluation studies, the Bayesian method. We also use a panel semi-parametric model to estimate the dose–response function for continuous treatment variables. The result suggests that there are more casualties in areas with better connectivity and accessibility, where more attention should be paid to safety countermeasures.

JOURNAL ARTICLE

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