Ariel Lopez
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Research Subjects
Research Interests
Ariel Lopez has a total of 17 co-authors. Here are the top co-authors by number of shared publications:
- Sebastian Seriani
Escuela de Ingeniería de Construcción y Transporte, Pontifícia Universidad Católica de Valparaíso, Valparaíso 2362804, Chile
7 shared publications - Vicente Aprigliano
Escuela de Ingeniería de Construcción y Transporte, Pontificia Universidad Católica de Valparaíso, Avda Brasil 2147, Valparaíso 2362804, Chile
6 shared publications - Alvaro Peña
Escuela de Ingeniería de Construcción y Transporte, Pontificia Universidad Católica de Valparaíso, Avenida Brasil 2147, Valparaíso 2362804, Chile
4 shared publications - Taku Fujiyama
Faculty of Civil, Environmental and Geomatic Engineering, University College London, Chadwick Building, Gower St., London WC1E 6BT, UK
4 shared publications - Bernardo Arredondo
Escuela de Ingeniería de Construcción y Transporte, Pontifica Universidad Católica de Valparaíso, Valparaíso 2362804, Chile
3 shared publications - Anibal Tapia
Facultad de Ingeniería y Ciencias Aplicadas, Universidad de los Andes, Santiago 7550000, Chile
1 shared publication
Latest Publications
- Open Access
- 24 July 2025
- Published by MDPI AG in Applied Sciences
- Vol. 15 (15) , 8256
Passenger Service Time at the Platform–Train Interface: A Review of Variability, Design Factors, and Crowd Management Implications Based on Laboratory Experiments
This paper reviews the variability of passenger service time (PST) at the platform–train interface (PTI), a critical performance indicator in metro systems shaped by the infrastructure design, affecting passenger behavior and accessibility. Despite its operational importance, PST remains underexplored in relation to crowd management strategies. This review synthesizes findings from empirical and experimental research to clarify the main factors influencing PST and their implications for platform-level interventions. Key contributors to PST variability include door width, gap dimensions, crowd density, and user characteristics such as mobility impairments. Design elements—such as platform edge doors, yellow safety lines, and vertical handrails—affect flow efficiency and spatial dynamics during boarding and alighting. Advanced tracking and simulation tools (e.g., PeTrack and YOLO-based systems) are identified as essential for evaluating pedestrian behavior and supporting Level of Service (LOS) analysis. To complement traditional LOS metrics, the paper introduces Level of Interaction (LOI) and a multidimensional LOS framework that captures spatial conflicts and user interaction zones. Control strategies such as platform signage, seating arrangements, and visual cues are also reviewed, with experimental evidence showing that targeted design interventions can reduce PST by up to 35%. The review highlights a persistent gap between academic knowledge and practical implementation. It calls for greater integration of empirical evidence into policy, infrastructure standards, and operational contracts. Ultimately, it advocates for human-centered, data-informed approaches to PTI planning that enhance efficiency, inclusivity, and resilience in high-demand transit environments.
- 24 July 2025
- Published by MDPI AG in Applied Sciences
- Vol. 15 (15) , 8256
Open AccessPassenger Service Time at the Platform–Train Interface: A Review of Variability, Design Factors, and Crowd Management Implications Based on Laboratory Experiments
This paper reviews the variability of passenger service time (PST) at the platform–train interface (PTI), a critical performance indicator in metro systems shaped by the infrastructure design, affecting passenger behavior and accessibility. Despite its operational importance, PST remains underexplored in relation to crowd management strategies. This review synthesizes findings from empirical and experimental research to clarify the main factors influencing PST and their implications for platform-level interventions. Key contributors to PST variability include door width, gap dimensions, crowd density, and user characteristics such as mobility impairments. Design elements—such as platform edge doors, yellow safety lines, and vertical handrails—affect flow efficiency and spatial dynamics during boarding and alighting. Advanced tracking and simulation tools (e.g., PeTrack and YOLO-based systems) are identified as essential for evaluating pedestrian behavior and supporting Level of Service (LOS) analysis. To complement traditional LOS metrics, the paper introduces Level of Interaction (LOI) and a multidimensional LOS framework that captures spatial conflicts and user interaction zones. Control strategies such as platform signage, seating arrangements, and visual cues are also reviewed, with experimental evidence showing that targeted design interventions can reduce PST by up to 35%. The review highlights a persistent gap between academic knowledge and practical implementation. It calls for greater integration of empirical evidence into policy, infrastructure standards, and operational contracts. Ultimately, it advocates for human-centered, data-informed approaches to PTI planning that enhance efficiency, inclusivity, and resilience in high-demand transit environments.
- Open Access
- 7 March 2025
- Published by MDPI AG in Applied Sciences
- Vol. 15 (6) , 2889
Infrastructure Typology of Metro Stations: A Passenger Simulation Approach Based on Efficiency and Capacity
The efficiency of a metro station is determined by the transfer capacity it has on the platform. This is the critical area and the primary motivation for this research. This study analyzed the impact of platform typology on the efficiency and capacity of metro stations. Through the study, the simulation of different typologies, the design logic of the station was analyzed from the ground up, examining each of its components from both a physical and operational perspective. To evaluate the efficiency and capacity of a platform configuration, Fruin’s level of service or LOS is used to compare the efficiency across different platform typologies, allowing for the quantification of constraints within the platform configuration. The platform configuration, access points, and connectors impact the station’s transfer capacity. This configuration must align with the environmental conditions and the station’s role within the system as a whole. The mixed-platform station configuration is twice as efficient as a central platform station and slightly more efficient than a side-platform station, with variations depending on station usage, environment, and position within the network. Under symmetric flow conditions, the side platform is more efficient, reaching a LOS D (density between 1.54 and 3.57 passengers/m2). Under asymmetric flow conditions, the central platform is more efficient, reaching a LOS D. However, under both symmetric and asymmetric flow conditions, the mixed platform is more efficient than the two previous configurations, and this design is proposed as the most suitable for transfer station designs, reaching a LOS D. A modular station design is proposed, where a mixed station is built with the capacity to expand based on increased passenger demand. This means constructing a central-platform station initially, and when the capacity is reached (LOS = E or density of 5.26 passengers/m2), the second phase is built, adding lateral platforms, thus converting it into a mixed station and doubling its capacity.
- 7 March 2025
- Published by MDPI AG in Applied Sciences
- Vol. 15 (6) , 2889
Open AccessInfrastructure Typology of Metro Stations: A Passenger Simulation Approach Based on Efficiency and Capacity
The efficiency of a metro station is determined by the transfer capacity it has on the platform. This is the critical area and the primary motivation for this research. This study analyzed the impact of platform typology on the efficiency and capacity of metro stations. Through the study, the simulation of different typologies, the design logic of the station was analyzed from the ground up, examining each of its components from both a physical and operational perspective. To evaluate the efficiency and capacity of a platform configuration, Fruin’s level of service or LOS is used to compare the efficiency across different platform typologies, allowing for the quantification of constraints within the platform configuration. The platform configuration, access points, and connectors impact the station’s transfer capacity. This configuration must align with the environmental conditions and the station’s role within the system as a whole. The mixed-platform station configuration is twice as efficient as a central platform station and slightly more efficient than a side-platform station, with variations depending on station usage, environment, and position within the network. Under symmetric flow conditions, the side platform is more efficient, reaching a LOS D (density between 1.54 and 3.57 passengers/m2). Under asymmetric flow conditions, the central platform is more efficient, reaching a LOS D. However, under both symmetric and asymmetric flow conditions, the mixed platform is more efficient than the two previous configurations, and this design is proposed as the most suitable for transfer station designs, reaching a LOS D. A modular station design is proposed, where a mixed station is built with the capacity to expand based on increased passenger demand. This means constructing a central-platform station initially, and when the capacity is reached (LOS = E or density of 5.26 passengers/m2), the second phase is built, adding lateral platforms, thus converting it into a mixed station and doubling its capacity.
- Open Access
- 31 January 2025
- Published by MDPI AG in Applied Sciences
- Vol. 15 (3) , 1489
Time–Space Analysis of Transport Infrastructures: A Pilot Study of Shibuya-Type Crossings for Signalized Intersections in Developing Cities
Cities are growing larger, and congestion is becoming a major issue. Walking is increasingly becoming an important mode of transport in developing cities. One of the reasons for the high death toll is the lack of pedestrian facilities at transport infrastructures such as signalized intersections, where a conflict arises between vehicles turning right and pedestrians crossing at different speeds. This conflict, known as the vehicle–pedestrian conflict (in right-driving jurisdictions), occurs when the green light for vehicles is shared with the green pedestrian light. Additionally, if the intersection is congested due to high pedestrian flow, vehicles will turn right only during the yellow light, trying to find a gap in the pedestrian flow. As a result, delays increase for both pedestrians and vehicles, reducing the intersection’s capacity. To reduce the vehicle–pedestrian conflict, various pedestrian facilities can be implemented, such as Shibuya-type crossings, which include an exclusive pedestrian phase and diagonal crossing. When applying this type of solution, vehicle delays are reduced up to 81% on average, increasing the efficiency and safety of the space used at the intersection. However, pedestrian delays might increase up to 5 times, due to the need to wait for the third exclusive phase for them to cross the intersection in all directions. The method is applied in a case of study in Valparaiso, Chile, and therefore can be expanded in further research to other developing cities in Chile and specifically Latin America.
- 31 January 2025
- Published by MDPI AG in Applied Sciences
- Vol. 15 (3) , 1489
Open AccessTime–Space Analysis of Transport Infrastructures: A Pilot Study of Shibuya-Type Crossings for Signalized Intersections in Developing Cities
Cities are growing larger, and congestion is becoming a major issue. Walking is increasingly becoming an important mode of transport in developing cities. One of the reasons for the high death toll is the lack of pedestrian facilities at transport infrastructures such as signalized intersections, where a conflict arises between vehicles turning right and pedestrians crossing at different speeds. This conflict, known as the vehicle–pedestrian conflict (in right-driving jurisdictions), occurs when the green light for vehicles is shared with the green pedestrian light. Additionally, if the intersection is congested due to high pedestrian flow, vehicles will turn right only during the yellow light, trying to find a gap in the pedestrian flow. As a result, delays increase for both pedestrians and vehicles, reducing the intersection’s capacity. To reduce the vehicle–pedestrian conflict, various pedestrian facilities can be implemented, such as Shibuya-type crossings, which include an exclusive pedestrian phase and diagonal crossing. When applying this type of solution, vehicle delays are reduced up to 81% on average, increasing the efficiency and safety of the space used at the intersection. However, pedestrian delays might increase up to 5 times, due to the need to wait for the third exclusive phase for them to cross the intersection in all directions. The method is applied in a case of study in Valparaiso, Chile, and therefore can be expanded in further research to other developing cities in Chile and specifically Latin America.
- Open Access
- 24 January 2025
- Published by MDPI AG in Applied Sciences
- Vol. 15 (3) , 1221
An Experimental Pilot Approach to Evaluate the Infrastructure Accessibility and Level of Service at Metro Station Platforms
Metro stations are essential for daily commuting, but overcrowding due to increased demand can severely impact infrastructure quality and passenger experience. The Level of Service (LOS), a key indicator of congestion, is influenced by factors such as density, flow, and speed, and poor LOS leads to issues like longer boarding times, overcrowded platforms, and reduced accessibility, especially for vulnerable populations. To address these challenges, the study explores innovative solutions to improve platform design infrastructure for better accessibility and LOS, aligning sustainable development goals to create safer, more inclusive transport systems. This study presents two strategies designed to reduce passenger congestion at Francia station on the Valparaíso metro platform infrastructures. The strategies, tested in experimental scenarios, showed minimal differences in boarding and alighting times, with less than a one-second average variation between the two. However, survey results revealed that passengers preferred the strategy “let passengers alight before boarding the train”, as it provided greater comfort and accessibility, reducing the number of passengers per door and improving the LOS from level C to B. Despite the minimal intervention in the experiments, the results suggest potential operational improvements. Future research will focus on measuring passengers’ emotional responses using psychophysiological data to further evaluate the suitability of the proposed strategies.
- 24 January 2025
- Published by MDPI AG in Applied Sciences
- Vol. 15 (3) , 1221
Open AccessAn Experimental Pilot Approach to Evaluate the Infrastructure Accessibility and Level of Service at Metro Station Platforms
Metro stations are essential for daily commuting, but overcrowding due to increased demand can severely impact infrastructure quality and passenger experience. The Level of Service (LOS), a key indicator of congestion, is influenced by factors such as density, flow, and speed, and poor LOS leads to issues like longer boarding times, overcrowded platforms, and reduced accessibility, especially for vulnerable populations. To address these challenges, the study explores innovative solutions to improve platform design infrastructure for better accessibility and LOS, aligning sustainable development goals to create safer, more inclusive transport systems. This study presents two strategies designed to reduce passenger congestion at Francia station on the Valparaíso metro platform infrastructures. The strategies, tested in experimental scenarios, showed minimal differences in boarding and alighting times, with less than a one-second average variation between the two. However, survey results revealed that passengers preferred the strategy “let passengers alight before boarding the train”, as it provided greater comfort and accessibility, reducing the number of passengers per door and improving the LOS from level C to B. Despite the minimal intervention in the experiments, the results suggest potential operational improvements. Future research will focus on measuring passengers’ emotional responses using psychophysiological data to further evaluate the suitability of the proposed strategies.
- Open Access
- 25 July 2024
- Published by MDPI AG in Applied Sciences
- Vol. 14 (15) , 6515
The Pedestrian Level of Service in Metro Stations: A Pilot Study Based on Passenger Detection Techniques
The platform–train interface (PTI) is one of the most complex spaces in metro stations. At the PTI, the interaction of boarding and alighting causes a high number of passengers to be present, affecting the boarding and alighting time, among other variables related to safety and efficiency. This research was performed to develop a multidimensional level of service for passengers by means of observing existing stations. The methodology included five dimensions of the level of service (passenger behaviour, train design, passenger characteristics, train operation, and platform built environment), and detection techniques based on a tracking system. The stations are operating urban services in Valparaiso Metro (Chile). The results show that there is a relationship between the speed of passengers and the detected passengers, among other variables. In addition, the dispersion of passengers is analysed at the PTI. Further research will include other types of stations and conditions.
- 25 July 2024
- Published by MDPI AG in Applied Sciences
- Vol. 14 (15) , 6515
Open AccessThe Pedestrian Level of Service in Metro Stations: A Pilot Study Based on Passenger Detection Techniques
The platform–train interface (PTI) is one of the most complex spaces in metro stations. At the PTI, the interaction of boarding and alighting causes a high number of passengers to be present, affecting the boarding and alighting time, among other variables related to safety and efficiency. This research was performed to develop a multidimensional level of service for passengers by means of observing existing stations. The methodology included five dimensions of the level of service (passenger behaviour, train design, passenger characteristics, train operation, and platform built environment), and detection techniques based on a tracking system. The stations are operating urban services in Valparaiso Metro (Chile). The results show that there is a relationship between the speed of passengers and the detected passengers, among other variables. In addition, the dispersion of passengers is analysed at the PTI. Further research will include other types of stations and conditions.
- Open Access
- 24 January 2024
- Published by MDPI AG in Sustainability
- Vol. 16 (3) , 998
The Effect of Seat Layout on the Interaction of Passengers Inside the Train Carriage: An Experimental Approach for Urban Services
The platform–train interface (PTI) is one of the most complex spaces in metro stations. At the PTI, the interaction of passengers boarding and alighting reaches high density, affecting the boarding and alighting time, among other variables related to safety and efficiency. Developing research was performed to study the effect of seat layout on the interaction of passengers by means of experiments in a controlled environment. The laboratory facility included a mock-up of a train carriage and its adjacent platform. The train was representative of urban services in the Valparaiso Metro (Chile). The results showed that seat layout changed the patterns of interaction of passengers inside the train carriage. If seats were parallel to the movement of the train, then wider corridors inside the train were generated, and therefore, the number of passengers using this space could increase up to three times. However, in urban services, passengers were located closer to the train doors to be prepared for alighting, and therefore, the passenger numbers at the central hall remained the same with the seat layout. In addition, most passengers always used seats even if they were in a different position due to the aforementioned reasons. Further research will include passengers with reduced mobility and remaining inside the train while others are alighting to identify the effect of the space used on the interaction of passengers inside the train.
- 24 January 2024
- Published by MDPI AG in Sustainability
- Vol. 16 (3) , 998
Open AccessThe Effect of Seat Layout on the Interaction of Passengers Inside the Train Carriage: An Experimental Approach for Urban Services
The platform–train interface (PTI) is one of the most complex spaces in metro stations. At the PTI, the interaction of passengers boarding and alighting reaches high density, affecting the boarding and alighting time, among other variables related to safety and efficiency. Developing research was performed to study the effect of seat layout on the interaction of passengers by means of experiments in a controlled environment. The laboratory facility included a mock-up of a train carriage and its adjacent platform. The train was representative of urban services in the Valparaiso Metro (Chile). The results showed that seat layout changed the patterns of interaction of passengers inside the train carriage. If seats were parallel to the movement of the train, then wider corridors inside the train were generated, and therefore, the number of passengers using this space could increase up to three times. However, in urban services, passengers were located closer to the train doors to be prepared for alighting, and therefore, the passenger numbers at the central hall remained the same with the seat layout. In addition, most passengers always used seats even if they were in a different position due to the aforementioned reasons. Further research will include passengers with reduced mobility and remaining inside the train while others are alighting to identify the effect of the space used on the interaction of passengers inside the train.
- Open Access
- 10 October 2023
- Published by MDPI AG in Applied Sciences
- Vol. 13 (20) , 11117
Analyzing Escalator Infrastructures: A Pilot Study in Santiago Metro
The behavior of passengers in urban railway stations (i.e., metro stations) is dependent on environmental, cultural, and temporal factors. This affects how escalator infrastructures are used, with some passengers standing on one side of the steps to allow others to walk and, in other cases, others standing or walking on both sides of the steps. In this research, escalator infrastructures were studied to better understand the relationship between different conditions and passenger behaviors through a method based on video cameras, passenger detection techniques, and a simulation framework. The results indicate that passenger behavior could affect escalator infrastructure as it varies significantly depending on the time of day, type of station, local culture, and other environmental factors. The implications of these findings for the planning and design of the infrastructure of railway stations are discussed, and practical recommendations are proposed to improve the efficiency of escalator usage in urban railway stations.
- 10 October 2023
- Published by MDPI AG in Applied Sciences
- Vol. 13 (20) , 11117
Open AccessAnalyzing Escalator Infrastructures: A Pilot Study in Santiago Metro
The behavior of passengers in urban railway stations (i.e., metro stations) is dependent on environmental, cultural, and temporal factors. This affects how escalator infrastructures are used, with some passengers standing on one side of the steps to allow others to walk and, in other cases, others standing or walking on both sides of the steps. In this research, escalator infrastructures were studied to better understand the relationship between different conditions and passenger behaviors through a method based on video cameras, passenger detection techniques, and a simulation framework. The results indicate that passenger behavior could affect escalator infrastructure as it varies significantly depending on the time of day, type of station, local culture, and other environmental factors. The implications of these findings for the planning and design of the infrastructure of railway stations are discussed, and practical recommendations are proposed to improve the efficiency of escalator usage in urban railway stations.