Cluster Analysis for Diminishing Heterogeneous Opinions of Service Quality Public Transport Passengers

[EN] One of the principal measures that public transport administrations are following for reaching a sustainable transportation in the cities consists on attract a higher number of citizens towards the use of public transport modes, by offering high quality services. Collecting users opinions is the best way of detecting where the service is failing and which aspects are been provided successfully. The main problem that has to be faced for analyzing service quality is the subjective nature of its measurement, offering heterogeneous assessments among passengers about the service. Stratifying the sample of users on segments of passengers which have more uniform opinions about the service can help to reduce this heterogeneity. This stratification usually is conducted based on the social and demographic characteristics of the passengers. However, there are more advance techniques that permits to identify more homogeneous groups of users. One of these techniques is the Cluster Analysis, which is a data mining technique that can be used for segmenting the sample of passengers on groups that share some common characteristics, and that have more homogeneous perceptions about the service. This technique has been applied in other fields of transport engineering but it has never been applied for searching homogeneous groups of users with regards to service quality evaluation in a public transport service. For this reason, the aim of this work is to find groups of passengers that perceive the quality of the service in a more homogeneous way, and to apply to this clusters a suitable statistic technique that permit us to discover which are the variables that more influence the passengers¿ overall evaluation about the service. The comparison among the results of each cluster will show considerable differences among them and also with the results obtained using the global sample.This study is sponsored by the Consejería de Innovación, Ciencia y Economía of the Junta de Andalucía (Spain) through the Excellence Research Project denominated Q-METROBUS-Quality of service indicator for METROpolitan public BUS transport services . The authors also acknowledge the Granada Consorcio de Transportes for making the data set available for this study. Likewise, Griselda López wishes to express her acknowledgement to the regional ministry of Economy, Innovation and Science of the regional government of Andalusia (Spain) for their scholarship to train teachers and researchers in Deficit AreasDe Oña, R.; López-Maldonado, G.; Díez De Los Ríos, F.; De Oña, J. (2014). Cluster Analysis for Diminishing Heterogeneous Opinions of Service Quality Public Transport Passengers. Procedia - Social and Behavioral Sciences. 162:459-466. https://doi.org/10.1016/j.sbspro.2014.12.227S45946616

Massive Stars as Major Factories of Galactic Cosmic Rays

The identification of major contributors to the locally observed fluxes of Cosmic Rays (CRs) is a prime objective towards the resolution of the long-standing enigma of CRs. We report on a compelling similarity of the energy and radial distributions of multi-TeV CRs extracted from observations of very high energy (VHE) $\gamma$-rays towards the Galactic Center (GC) and two prominent clusters of young massive stars, Cyg~OB2 and Westerlund~1. This resemblance we interpret as a hint that CRs responsible for the diffuse VHE $\gamma$-ray emission from the GC are accelerated by the ultracompact stellar clusters located in the heart of GC. The derived $1/r$ decrement of the CR density with the distance from a star cluster is a distinct signature of continuous, over a few million years, CR injection into the interstellar medium. The lack of brightening of the $\gamma$-ray images toward the stellar clusters excludes the leptonic origin of $\gamma$-radiation. The hard, $\propto E^{-2.3}$ type power-law energy spectra of parent protons continues up to $\sim$ 1 PeV. The efficiency of conversion of kinetic energy of stellar winds to CRs can be as high as 10 percent implying that the young massive stars may operate as proton PeVatrons with a dominant contribution to the flux of highest energy galactic CRs.Comment: minor revisions have been applied to address the referees' comments, conclusion unchange

Is it possible to attract private vehicle users towards public transport? Understanding the key role of service quality, satisfaction and involvement on behavioral intentions

This paper contributes to the public transport literature by ascertaining the role of involvement upon the service quality-satisfaction-behavioral intentions paradigm from the point of view of private vehicle users. This is the first study that provides a comprehensive understanding of this framework based on the private vehicle users’ perspective. The added value of this research is that, by using a structural equation modeling approach, it provides a comparison of alternative models and uses data from different samples collected in five large metropolitan areas (Berlin, Lisbon, London, Madrid and Rome) for modeling validation. In addition, a SEM-MIMIC approach was applied for controlling the heterogeneity of data due to specific characteristics of the interviewee (territorial setting, place of residence, demographic and socio-economic characteristics and travel related variables). The findings show that involvement is a full mediator between satisfaction and behavioral intentions, and that satisfaction is a full mediator between service quality and involvement. Furthermore, the SEM-MIMIC results revealed that the four latent factors investigated (service quality, satisfaction, involvement and behavioral intentions) dealt with highly heterogenous data. However, the most important finding is that private vehicle users’ involvement is the factor that contributes most to their behavioral intentions towards public transport. Hence, public transport managers might benefit from these outcomes when establishing detailed policies and specific guidelines for public transport systems to engage private vehicle users in a higher degree of usage of public transport services.Spanish Government TRA2015-66235-

Transit service quality analysis using cluster analysis and decision trees: a step forward to personalized marketing in public transportation

[EN] A transit service quality study based on cluster analysis was performed to extract detailed customer profiles sharing similar appraisals concerning the service. This approach made it possible to detect specific requirements and needs regarding the quality of service and to personalize the marketing strategy. Data from various customer satisfaction surveys conducted by the Transport Consortium of Granada (Spain) were analyzed to distinguish these groups; a decision tree methodology was used to identify the most important service quality attributes influencing passengers overall evaluations. Cluster analysis identified four groups of passengers. Comparisons using decision trees among the overall sample of all users and the different groups of passengers identified by cluster analysis led to the discovery of differences in the key attributes encompassed by perceived quality.The authors also acknowledge the Granada Consorcio de Transportes for making the data set available for this study. Griselda Lopez wishes to express her acknowledgement to the regional ministry of Economy, Innovation and Science of the regional government of Andalusia (Spain) for their scholarship to train teachers and researchers in Deficit Areas. Rocio de Ona wishes to express her acknowledgement to the regional ministry of Economy, Innovation and Science of the regional government of Andalusia (Spain) for the Excellence Research Project denominated "Q-METROBUS-Quality of service indicator for METROpolitan public BUS transport services'', co-funded with Feder.De Oña, J.; De Oña, R.; López-Maldonado, G. (2015). Transit service quality analysis using cluster analysis and decision trees: a step forward to personalized marketing in public transportation. Transportation. 43(5):725-747. https://doi.org/10.1007/s11116-015-9615-0S725747435Abou Zeid, M., Ben-Akiva, M.: A model of travel happiness and mode switching, in choice modelling: the state-of-the-art and the state-of-practice. In: Hess S., Daly A. (eds.) Proceedings from the Inaugural International Choice Modelling Conference, pp. 289–307. Emerald Group Publishing Limited (2010)Akaike, H.: Factor analysis and AIC. Psychome 52, 317–332 (1987)Breiman, L., Friedman, J., Olshen, R., Stone, C.: Classification and Regression Trees. Chapman and Hall, Belmont, CA (1984)Chang, L.Y., Wang, H.W.: Analisys of traffic injury severity: an application of non-parametric classification tree techniques. Accid. Anal. Prev. 38, 1019–1027 (2006)Cheung, K.-W., Kwok, J., Law, M.H., Tsui, K.-C.: Mining customer product ratings for personalized marketing. Decis. Support Syst. 35, 231–243 (2003)De Oña, J., de Oña, R., Calvo, F.J.: A classification tree approach to identify key factors of transit service quality. Expert Syst. Appl. 39, 11164–11171 (2012)De Oña, R., de Oña, J.: Analyzing transit service quality evolution using decision trees and gender segmentation. WIT Trans Built Environ 130, 611–621 (2013)De Oña, J., de Oña, R., Eboli, L., Mazzulla, G.: Perceived service quality in bus transit service: a structural equation approach. Transp. Policy 29, 219–226 (2013a)De Oña, J., López, G., Mujalli, R.O., Calvo, F.J.: Analysis of traffic accidents on rural highways using Latent Class Clustering and Bayesian Networks. Accid. Anal. Prev. 51, 1–10 (2013b)De Oña, J., de Oña, R., Eboli, L., Mazzulla, G.: Heterogeneity in perceptions of service quality among groups of railway passengers. Int J Sustain Transp 9(8), 612–626 (2014a)De Oña, R., Eboli, L., Mazzulla, G.: Key factors affecting rail service quality. A decision tree approach. Transport 29(1), 75–83 (2014b)De Oña, J., de Oña, R., Garrido, C.: Extracting importance of attributes from customer satisfaction surveys with data mining: decision trees and neural networks. In: Proceedings of the Transportation Research Board 94th Annual Meeting, Washington, DC, 11–15 Jan 2015Dell’Olio, L., Ibeas, A., Cecín, P.: Modelling user perception of bus transit quality. Transp. Policy 17(6), 388–397 (2010)Dell’Olio, L., Ibeas, A., Cecín, P.: The quality of service desired by public transport users. Transp. Policy 18(1), 217–227 (2011)Depaire, B., Wets, G., Vanhoof, K.: Traffic accident segmentation by means of latent class clustering. Accid. Anal. Prev. 40(4), 1257–1266 (2008)Duarte, A., Garcia, C., Giannarakis, G., Limão, S., Litinas, N., Polydoropoulou, A.: New approaches in transport planing: happiness and transport economics. Netnomics. Economic Research and Electronic Networking, Springer Netherlands, 1385–9587 (Print) 1573–7071 (Online) (2008)Eboli, L., Mazzulla, G.: Service quality attributes affecting customer satisfaction for bus transit. J Public Transp 10(3), 21–34 (2007)Eboli, L., Mazzulla, G.: Willingness-to-pay of public transport users for improvement in service quality. Eur Transp 38, 107–118 (2008)Eboli, L., Mazzulla, G.: How to capture the passengers’ point of view on a transit service through rating and choice options. Transp Rev 30, 435–450 (2010)Eboli, L., Mazzulla, G.: Performance indicators for an objective measure of public transport service quality. Eur Transp 51, 1–21 (2012)Ettema, D., Garling, T., Eriksson, L., Friman, M., Olsson, L.E., Fujii, S.: Satisfaction with travel and subjective well-being (SWB): development and tests of a measurement tool. Transp. Res. Part F 14, 167–175 (2011)Fraley, C., Raftery, A.E.: How many clusters? Which clustering method? Answers via model-based cluster analysis. Comput J 41, 578–588 (1998)Gärling, T., Fujii, S.: Travel behavior modification: theories, methods, and programs. In: Kitamura, R., Yoshi, T., Yamamoto, T. (eds.), The Expanding Sphere of Travel Behavior Research. IATBR, 97–128 (2009)Garrido, C., de Oña, R., de Oña, J.: Neural networks for analysing service quality in public transportation. Expert Syst. Appl. 4, 6830–6838 (2014)Hair Jr, J.F., Anderson, R.E., Tatham, R.L., Black, W.C.: Multivariate Data Analysis. Prentice Hall, Englewood Cliffs, NJ (1998)Hensher, D.A., Stopher, P., Bullock, P.: Service quality: developing a service quality index in the provision of commercial bus contracts. Transp. Res. Part A 37, 499–517 (2003)Hensher, D.A., Mulley, C., Yahya, N.: Passenger experience with quality-enhanced bus service: the tyne and wear ‘superoute’ services. Transportation 37(2), 239–256 (2010)INPHORMM: Case Studies of Transport Information and Publicity/Marketing Campaigns to Reduce Car Use and Promote Cycling, Walking and Public Transport. INPHORMM Deliverable D2 to the European Commission. Transport Studies Group. University of Westminster, and Partners, London (1998)Irfan Syed, M., Mui, H.K.D., Shahbaz, S.: Service quality in rail transport of Pakistan: a passenger perspective? In: Paper presented at the 3rd SAICON: International Conference on Management, Business Ethics and Economics (ICMBEE), Lahore, Pakistan, 28–29 Dec 2011Karlaftis, M., Tarko, A.: Heterogeneity considerations in accident modeling. Accid. Anal. Prev. 30(4), 425–433 (1998)Kashani, A.T., Mohaymany, A.S.: Analysis of the traffic injury severity on two-lane, two-way rural roads based on classification tree models. Saf. Sci. 49, 1314–1320 (2011)Ma, J., Kockelman, K.: Crash frequency and severity modeling using clustered data from Washington state. In: IEEE Intelligent Transportation Systems Conference, Toronto, Canadá (2006)Magidson, J., Vermunt, J.K.: Latent class models for clustering: a comparison with K-means. Can J Mark Res 20, 37–44 (2002)Mahmoud, M., Hine, J.: Using AHP to measure the perception gap between current and potential users of bus services. Transp Plan Technol 36(1), 4–23 (2013)McLachlan, G.J., Peel, D.: Finite Mixture Models. Wiley, New York (2000)Ory, D.T., Mokhtarian, P.L.: When is getting there half of the fun? Modelling the liking for travel. Transp. Res. Part A 39(2–3), 97–123 (2005)Outwater, M.L., Castleberry, S., Shiftan, Y., Ben-Akiva, M., Zhou, Y.S., Kuppam, A.: Attitudinal market segmentation approach to mode choice and ridership forecasting: structural equation modeling. Transp. Res. Rec. 1854, 32–42 (2003)Paquette, J., Bellavance, F., Cordeau, J., Laporte, G.: Measuring quality of service in dial-a-ride operations: the case of a canadian city. Transportation 39(3), 539–564 (2012)Parkan, C.: Measuring the operational performance of a public transit company. Int J Oper Prod Manag 22(6), 693–720 (2002)Raftery, A.E.: A note on Bayes factors for log-linear contingency table models with vague prior information. J. Roy. Stat. Soc. B 48, 249–250 (1986)Redman, L., Friman, M., Gärling, T., Hartig, T.: Quality attributes of public transport that attract car users: a research review. Transp. Policy 25, 119–127 (2013)Rietveld, P.: Six reasons why supply oriented indicators systematically overestimate service quality in public transport. Transp Rev 25(3), 319–328 (2005)Sanjust, B., Meloni, I., Spissu, E.: An impact assessment of a travel behavior change program: a case study of a light rail service in Cagliari, Italy. Case study of transport policy. ( http://dx.doi.org/10.1016/j.cstp.2014.04.002 ) (2014, in press)Sepúlveda, R.A.: Contribuciones al Análisis de Clases latentes en Presencia de Dependencia Local. Thesis, University of Salamanca (2004)TAPESTRY: Best Practice Guidelines (Deliverable 5). Report to the European Commission (DGTREN) Travel and Transport Research, Nottingham and Partners (2003)Vermunt, J.K., Magidson, J.: Latent GOLD 4.0 user’s guide. Statistical Innovations Inc., Belmont, MA (2005)Vesanen, J.: What is personalization? A conceptual framework. Eur. J. Mark. 41(5/6), 409–418 (2007)Xie, C., Lu, J., Parkany, E.: Work travel mode choice modelling with data mining. Transp. Res. Rec. 1854, 03–4338 (2003

Analysis of transit quality of service through segmentation and classification tree techniques

Perceptions about the quality of service are very different among public transport (PT) users. Users’ perceptions are heterogeneous for many reasons: the qualitative aspects of PT service, users’ socio-economic characteristics, and the diversity of tastes and attitudes towards PT. By analysing different groups of users who share a common characteristic (e.g. socio-economic or travel behaviour), it is possible to homogenise user opinions about the quality of service. This paper studies quality as perceived by users of the metropolitan transit system of Granada (Spain) through a classification tree technique (classification and regression trees (CART)) based on five market segmentations (gender, age, frequency of use, reason for travelling, and type of ticket). CART is a non-parametric method that has a number of advantages compared to other methods that require a predefined underlying relationship between dependent and independent variables. The study is based on data gathered in several customer satisfaction surveys (non-research-oriented) conducted in the Granada metropolitan transit system. The models' outcomes show that some attributes are very important for almost all the market segments (punctuality and information), while others are not very relevant for any of the segments – most notably fare, despite the fact that fare was stated as very important by most of the passengers during the interviewConserjería de Innovación, Ciencia y Economía of the Junta de Andalucía (Spain) through the Excellence Research Project denominated “Q-METROBUS-Quality of service indicator for METROpolitan public BUS transport services”

In Search of Severity Dimensions of Traffic Conflicts for Different Simulated Mixed Fleets Involving Connected and Autonomous Vehicles

-is study aims to estimate the severity of con3icts that may arise from the introduction of connected and automated vehicles (CAVs) by examining the vehicle paths generated by microsimulations of mixed 3eets of human-driven vehicles and CAVs with di9erent levels of automation (L1-L4 vehicles). -e study assesses the severity of con3icts using a holistic approach that considers three dimensions: (1) proximity to collision, via the time-to-collision (TTC) indicator; (2) potential consequences of a con3ict, via single surrogate safety measures such as maximum speed (MaxS) and vehicle speed di9erence (DeltaS); and (3) a combination of both dimensions to assign severity scores, via TTC and velocity vectors. -e study’s >ndings suggest that moderate penetration rates of L3 and L4 vehicles (35–55%) show signi>cant di9erences in the number of traAc con3icts with varying TTC values. Additionally, high penetration rates of L3 and L4 vehicles (above 55%) result in lower values of con3ict consequences measures such as MaxS and DeltaS. Furthermore, the study shows that con3ict consequences decrease if the follower is a L3 or L4 vehicle. -e study’s >ndings also reveal that there is a considerable reduction in high severity con3icts when the penetration rate of CAV levels reaches 50%, and the full operation of L4 vehicles results in a 75.5% reduction in high severity con3icts. -erefore, this study provides valuable insight into the potential severe con3icts during the transition period from manual vehicle operation to full CAV operation. Overall, the study’s >ndings highlight the importance of assessing the severity of potential con3icts arising from the introduction of CAVs. By considering the proximity to collision and the potential consequences of con3icts, the study provides a comprehensive assessment of the severity of con3icts. -is information can inform the development of policies and strategies to ensure the safe and responsible introduction of CAVs into our transportation systems.Spanish Government PID2019-110741RA-I00CRUE-CBUA Gol

How does private vehicle users perceive the public transport service quality in large metropolitan areas? A European comparison

Support from Spanish Ministry of Economy and Competitiveness (Research Project TRA2015-66235-R) is gratefully acknowledged. Funding for open access charge: Universidad de Granada/CBUAMost studies on public transport service quality focus on the perspective of the public transport user, overlooking potential users, that is, private vehicle users. This paper explores the perception of private vehicle users about the quality of public transport. The objective is to identify the attributes that bear the greatest influence on the general satisfaction of the private vehicle user with respect to public transport in five major European cities: Berlin, Lisbon, London, Madrid and Rome. The analysis estimates the effect of 14 quality of service attributes on general satisfaction using Ordinal Logit Models (OLM), using data from an online survey sent to private vehicle users, with a similar sample size for each city (N > 500 per city). To analyse the heterogeneity of the perceptions, 20 models were calibrated: 15 models were calibrated controlling for location; and five models (one per city) were calibrated controlling for sociodemographic and mobility characteristics. Frequency, punctuality, intermodality, cost and cleanliness were identified as attributes exerting a significant effect on satisfaction in practically all the models, meaning they could be considered core attributes for private vehicle users. On a second level, a group of attributes were significant in a substantial number of models (service hours, proximity, speed, temperature and safety). Finally, the remaining attributes were only significant for specific cities or segments. The last two groups of attributes allowed to detect differences between cities and market segments.Spanish Ministry of Economy and Competitiveness TRA2015-66235-

Traffic Safety Sensitivity Analysis of Parameters Used for Connected and Autonomous Vehicle Calibration

Recently, the number of traffic safety studies involving connected and autonomous vehicles (CAVs) has been increasing. Due to the lack of information regarding the real behaviour of CAVs in mixed traffic flow, traffic simulation platforms are used to provide a reasonable approach for testing various scenarios and fleets. It is necessary to analyse how traffic safety is affected when key parameter assumptions are changed. The current study conducts a sensitivity analysis to identify the parameters used in CAV calibration that have the highest influence on traffic safety. Using a microsimulation-based surrogate safety assessment model approach (SSAM), traffic conflicts were identified, and a ceteris paribus analysis was conducted to measure the effect of gradually changing each parameter on the number of conflicts. Afterwards, a two-at-a-time sensitivity analysis was performed to explore the influence of simultaneously varying two parameters. The results revealed that reaction time, clearance, maximum acceleration, normal deceleration, and the sensitivity factor are key parameters. Studying these parameters two at a time revealed that low maximum acceleration, when combined with other parameters, consistently resulted in the highest number of conflicts, while combinations with short reaction time always yielded the best traffic safety results. This investigation broadens the understanding of CAV behaviour for future implementation for both manufacturers and researchers.Research Project PID2019-110741RA-I00, funded by the Spanish State Research Agency under Grant MCIN/AEI /10.13039/50110001103

CP-Odd Phase Effects in a Left-Right Symmetric Chargino Sector

The left-right supersymmetric model contains a right-handed gaugino, as well as several higgsinos, in addition to the minimal supersymmetric model. Thus several CP-noninvariant phases appear in this sector. We analyze their impact on chargino masses and find that only two combinations are physically relevant. We then study the production of charginos in e+e- annihilation and chargino decays into a sneutrino and a lepton, and investigate the effects of CP-phases. We also study the CP-odd asymmetry in the production and subsequent decay at the linear collider with longitudinally polarized beams and find a large enhancement when the decay channel to the right sneutrino is available. The effects of the phases in the left-right supersymmetric chargino sector are different from the minimal supersymmetric standard model, and signals from this sector would be able to distinguish between different gauge symmetries.Comment: 24 pages, 11 figures, minor clarifications in the model part, to be published in Phys. Rev.

UNDERSTANDING TRANSIT USERS IN ALGIERS: KEY QUALITY FACTORS AT THE RAILWAY SERVICES

[EN] Algerians citizens most often travel by foot on their daily trips because the lack of a homogeneous offer of public transit and intermodality throughout the city. Furthermore, the private vehicle is experiencing a notable increased use over the last few years. To curb this tendency, the government has launched a metro and a tramway system as key parts of a whole sustainable transport strategy. Guaranteeing the profitability of these modes of transport demands a high quality operation level focused on the users’ needs and requirements. While numerous studies have been carried out in developed countries for identifying the essential aspects of different transit modes, this area is still new in developing countries. Then, this paper aims to identify the key quality factors of the railway transit services in Algiers for advising transit authorities and managers towards the most appropriate policy measures. The railway transit services in Algiers consist on three modes of transport: the metro, the tramway (both started into operation in 2011), and a commuter rail system. A Principal Component Analysis combined with a regression model integrates the assessment approach. The results of this research highlight differences among the transit systems analyzed and provide useful insights for the Algiers government and transit authorities.Oña, RD.; Machado, JL.; Baouni, T.; Oña, JD. (2016). UNDERSTANDING TRANSIT USERS IN ALGIERS: KEY QUALITY FACTORS AT THE RAILWAY SERVICES. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 483-490. https://doi.org/10.4995/CIT2016.2015.4100OCS48349