Imperial College London


Faculty of EngineeringDepartment of Civil and Environmental Engineering

Associate Director/Head of Metro Benchmarking



+44 (0)20 7594 3974alexander.barron CV




607Skempton BuildingSouth Kensington Campus





Publication Type

14 results found

Ait Bihi Ouali L, Graham D, Trompet M, Barron Aet al., 2020, Gender differences in the perception of safety in public transport, Journal of the Royal Statistical Society Series A: Statistics in Society, Vol: 183, Pages: 737-769, ISSN: 0964-1998

Concerns over women's safety on public transport systems are commonly reported in the media. In this paper we develop statistical models to test for gender differences in the perception of safety and satisfaction on urban metros and buses using large-scale unique customer satisfaction data for 28 world cities over the period 2009 to 2018. Results indicate a significant gender gap in the perception of safety, with women being 10\% more likely than men to feel unsafe in metros (6% for buses). This gender gap is larger for safety than for overall satisfaction (3% in metros and 2.5% in buses), which is consistent with safety being one dimension of overall satisfaction. Results are stable across specifications and robust to inclusion of city-level and time controls. We find heterogeneous responses by sociodemographic characteristics. Data indicates 45% of women feel secure in trains and metro stations (respectively 55% in buses). Thus the gender gap encompasses more differences in transport perception between men and women rather than an intrinsic network fear. Additional models test for the influence of metro characteristics on perceived safety levels and find that that more acts of violence, larger carriages, and emptier vehicles decrease women's feeling of safety.

Journal article

Morse L, Trompet M, Barron A, Anderson R, Graham Det al., 2020, A benchmarking framework for understanding bus performance in the U.S., Benchmarking: an international journal, Vol: 27, Pages: 1533-1550, ISSN: 1463-5771

Purpose This paper describes a benchmarking framework applied to medium-sized urban public bus agencies in the United States which has overcome the challenges of data quality, comparability and understanding.Design/methodology/approach The benchmarking methodology described in this paper is based on lessons learned through seven years of development of a fixed route key performance indicator (KPI) system for the American Bus Benchmarking Group (ABBG). Founded in 2011, the ABBG is a group of public medium-sized urban bus agencies that compare performance and share best practices with peers throughout the United States. The methodology is adapted from the process used within international benchmarking groups facilitated by Imperial College and consists of four main elements: peer selection, KPI system development, processes to achieve high-quality data, and processes to understand relative performance and change.Findings The four main elements of the ABBG benchmarking methodology consist of eighteen sub-elements, which when applied overcome three main benchmarking challenges; comparability, data quality, and understanding. While serving as examples for the methodology elements, the paper provides specific insights into service characteristics and performance among ABBG agencies.Research limitations/implications The benchmarking approach described in this paper requires time and commitment and thus is most suitably applied to a concise group of agencies. Practical implications This methodology provides transit agencies, authorities and benchmarking practitioners a framework for effective benchmarking. It will lead to high-quality comparable data and a strong understanding of the performance context to serve as a basis for organizational changes, whether for policy, planning, operations, stakeholder communication, or program development. Originality/value The methodology, while consistent with recommendations from literature, is unique in its scale, in-depth validation

Journal article

Canavan S, Barron A, Cohen J, Graham DJ, Anderson RJet al., 2019, Best Practices in Operating High Frequency Metro Services, Transportation Research Record, ISSN: 0361-1981

© National Academy of Sciences: Transportation Research Board 2019. Most metro rail systems worldwide are facing increasing demand and the need to deliver additional capacity in key corridors. Although total capacity reflects the combination of train capacity and frequency, increasing frequency is the primary strategy to increase capacity on existing lines where infrastructure is fixed. Higher frequencies also increase efficiency, by attracting more passengers and making existing journeys faster, thereby making better use of expensive rail infrastructure and increasing both metro revenues and wider economics benefits to the cities they serve. This paper is based on a study conducted for the Community of Metros, a worldwide group of metro systems, which surveyed 17 high frequency lines. The paper first documents the characteristics of high frequency lines [with 25 trains per hour (tph) or more defined as “high frequency” and 30 tph or more as “very high frequency”] and presents the various constraints to higher frequency operations, including how they interact and the various possible solutions. Five main categories of constraints were identified, relating to signaling and train control, station and train crowding, fleet, terminal turnarounds, and service complexity. To achieve the highest frequencies, it is essential for metro systems to take a holistic approach and identify not only the immediate constraints but also secondary and tertiary constraints that may prevent the full benefits of improvements from being realized. This paper provides guidance to those operating, funding, planning, and designing metro systems in how to maximize frequency and thereby deliver greater benefits to riders, transit agencies, and stakeholders.

Journal article

Canavan S, Graham D, Anderson R, Barron Aet al., 2018, Urban metro rail demand: evidence from dynamic generalised method of moments (GMM) estimates using panel data, Transportation Research Record, Vol: 2672, Pages: 288-296, ISSN: 0361-1981

This paper estimates elasticities of demand for metro service with respect to fares, income, quality of service, population and network length. Data for 32 world metro systems covering the period from 1996 to 2015 are analysed within a dynamic panel data specification. Three key contributions are made. First, we collate a database for estimation that is more extensive than that used in previous studies. Second, the quality of the data we have available allows us to more accurately represent quality of service than has been possible previously. And lastly, we estimate and compare two different measures of demand. Our analysis finds a statistically significant negative fare elasticity of -0.25 in the long run for a passenger km specified model and -0.4 in the long run for a passenger journeys specified model, and a positive long run income elasticity of 0.17 and 0.18 for the passenger km and passenger journey models respectively. Regarding quality of service we find positive long run elasticities of 0.56 and 0.47 for the passenger km and passenger journey models respectively. Income levels, population and the size of the network are also found to be statistically significant and positive in nature. The results suggest passenger km and passenger journeys will increase more in response to changes in service (here represented by increased capacity) than to changes in fares, with the difference in elasticities of service and fares being more pronounced for passenger km.

Journal article

Barron A, Canavan S, Cohen J, Anderson Ret al., 2018, Operational impacts of platform doors in metros, Transportation Research Record, Vol: 2672, Pages: 266-274, ISSN: 0361-1981

Platform doors are increasingly installed by metros, primarily to improve safety. However, they have the potential for both positive and negative operational impacts, mostly by affecting dwell times at stations. Using data from the CoMET and Nova international metro benchmarking consortia of 33 metro systems, this paper seeks to understand and quantify these operational impacts. Overall, platform doors have a net negative impact on dwell times, leading to between 4 and 15 seconds of extra time per station stop. This is due to additional time for the larger doors to open and close slower passenger movements due to the additional distance between platforms and trains and, most importantly, extended departure delays after both sets of doors are closed caused by the need to ensure safety (that no one is trapped in the gap between the two sets of doors). This is a particular problem in mainland China, where metros conduct manual safety checks that require drivers to step out of trains onto platforms. However, despite longer dwell times, platform doors have a net positive impact on metro operations, largely due to the many safety benefits that also reduce delays and thereby improve service performance. There are also potential benefits regarding energy and ventilation. To mitigate the negative impacts, metros should seek to refine procedures and improve technology to reduce dwell time delays caused by platform doors. Reducing or eliminating these extra delays are essential to delivering efficient service and maximum capacity, provided that safety can be assured.

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-Series, Vol: 2650, Pages: 1-8, ISSN: 0361-1981

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

Journal article

Cohen JM, Barron AS, Anderson RJ, Graham DJet al., 2016, Impacts of Unattended Train Operations (UTO) on Productivity and Efficiency in Metropolitan Railways, Transportation Research Record-Series, Vol: 2534, Pages: 75-83, ISSN: 0361-1981

Urban metro subway systems (metros) around the world are choosing increasing levels of automation for new and existing lines: the global length of metro lines capable of unattended train operation (UTO) is predicted to triple in the next 10 years. Despite significant investment in this technology, empirical evidence for the financial and service quality impacts of UTO in metros remains scarce. This study used questionnaires and semistructured interviews with the Community of Metros and Nova Group benchmarking groups to assemble emerging evidence of how automation affected costs, staffing, service capacity, and reliability. The results from an analysis of data from 23 lines suggested that UTO could reduce staff numbers by 30% to 70%, with the amount of wage cost reduction depending on whether staff on UTO lines were paid more. On the basis of the experience of seven metros, the capital costs of lines capable of UTO were higher, but the internal rate of return had been estimated by two metros at 10% to 15%. Automated lines were capable of operating at the highest service frequencies of up to 42 trains per hour, and the limited available data suggested that automated lines were more reliable. The findings indicated that UTO was a means to a more flexible and reliable operating model that could increase metro productivity and efficiency. The study identified important work needed to understand the impacts of UTO and identify where statistical analyses would add value once sufficiently large data sets became available.

Journal article

Canavan S, Graham D, Melo P, Anderson R, Barron A, Cohen Jet al., 2016, The Impacts of Moving Block Signalling on Technical Efficiency: An Application of Propensity Score Matching on Urban Metro Rail Systems, Transportation Research Record, Vol: 2534, Pages: 68-74, ISSN: 0361-1981

This study tested the effect of introducing moving-block signaling on the technical efficiency of urban metro rail systems. The study used a panel data set of 27 urban metro systems across 20 countries for 2004 to 2012. When moving-block signaling was considered as a treatment, the effect of the associated benefits on output efficiency levels was able to be measured. Stochastic frontier analysis was employed to estimate technical efficiencies for each metro, and then propensity score matching was applied to evaluate the effect of the type of signaling on technical efficiency. The study allowed the selection of appropriate reference groups and accounted for confounding factors. The study is novel in its provision of empirical evidence of this nature. The results indicate that the technical efficiency of a metro can be improved by 11.5%.

Journal article

Cohen JM, Parasram R, Anderson R, Barron Aet al., 2015, Global trends in metro station organisation and management, 43rd European Transport Conference

Increased uptake of smart ticketing, mass availability of personal information technology,and roll-out of 4G and WiFi coverage within metropolitan railway systems, are leadingmetros to change the way they manage stations.

Conference paper

Cohen JM, Barron A, Anderson R, Graham Det al., 2015, 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

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

Conference paper

Cohen JM, Barron AS, Anderson RJ, 2014, Human Operational Support on UTO Lines, Publisher: Imperial College London

Metro automation is an increasing trend worldwide. This study investigated the realities of operating automated lines, focused on the following key questions: What staffing levels are used by metros, and what are the pros and consof each approach? Under what circumstances do metros choose to staff all trains on linesthat are capable of unattended operations? What technology is required to enable automated operations? Do the benefits of automation outweigh the additional investment?


Barron A, Melo PC, Cohen JM, Anderson RJet al., 2013, Passenger-Focused Management Approach to Measurement of Train Delay Impacts, Transportation Research Record, Vol: 2351, Pages: 46-53, ISSN: 0361-1981

Train delay incidents have major effects on transit service reliability and on customer satisfaction. Operators have long focused efforts on preventing such incidents. While this action is important, the fact that all transit operations inevitably face some degree of delay and disruption from incidents means that operators must also dedicate attention to reducing the duration of incidents and the time to restore normal operations after incidents occur. To be able to do this, it is necessary to measure the total impact of incidents on train service and customers. This research uses data from the CoMET and Nova metro benchmarking groups to investigate the ways in which transit operators can better measure the full effects of incidents on train service and customers. The key benefit of such a passenger-focused approach is that it enables transit managers to direct resources for incident response and recovery better, as well as support the case for strategic investments. This research has shown that most operators measure and report only the frequency of incidents. Of the 22 metros interviewed, only two were able to provide detailed data to estimate the number of passengers affected by incidents. It is no coincidence that the only two metros able to provide detailed data are in fact two of the most reliable in the group.

Journal article

Melo PC, Harris NG, Graham DJ, Anderson RJ, Barron Aet al., 2011, Determinants of Delay Incident Occurrence in Urban Metros, TRANSPORTATION RESEARCH RECORD, Pages: 10-18, ISSN: 0361-1981

Journal article

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