Posts tagged service reliability

Subjective Beliefs regarding Waiting Times in Public Transport Networks in the Netherlands, Greece, and Portugal

Waiting times in public transport networks (PTNs) are inherently uncertain for travellers and, similar to other service industries, such uncertainty is likely to be a major cause for anxiety and frustration (Maister, 1985). While real-time information regarding waiting times is an important development in mitigating such negative feelings, they do not completely remove uncertainty. Even when information is provided, travellers process it on the basis of their individual attitudes, habits, experiences, and contemporary contextual variables. Yet, previous studies on behavioural responses to travel time unreliability have either (unrealistically) assumed that travellers know the objective travel time distributions or have studied behaviour within the artificial context of travel simulators. Quantifying travellers’ attitudes and perceptions — subjective beliefs — regarding waiting times may be critical for assessment of travel satisfaction and subsequently choice behaviour.

In this research, a stated preference experiment is used to quantify travellers’ attitudes and perceptions — subjective beliefs — regarding waiting times in public transport networks in three European countries. Results and potential policy implications are presented at the European Transport Conference (ETC).

Find the ETC poster of Sanmay Shelat HERE

Impact assessment of new North/South metro line in Amsterdam

Large infrastructural projects are usually evaluated ex-ante before the decision to build the project is taken. However, after construction and opening of such project a thorough ex-post analysis is rare. In this paper we present an overview of such an evaluation study conducted in Amsterdam, capital of The Netherlands, including some first results. Research themes in the study are public transport, mobility and accessibility, public space and liveability and spatial economics. In this paper we focus on effects on public transport.

The new north-south metro line in Amsterdam became operational in summer 2018. This was accompanied by changes to the existing bus and tram network to provide feeder services to the new line, as well as to remove duplicate routes. Apart from adding significant capacity to the public transport network, the new line and the accompanying changes to the network are expected to improve travel times, reliability, accessibility and comfort levels (at least on average; not for all individual travellers).
The changes in such service quality attributes is expected to lead to a change in travel behaviour in terms of public transport route choice, mode choice (between public transport and private modes or within public transport), destination choice, departure time choice or addition of new trips (induced demand).
The objective of this study is to identify the main effects of the new metro line on existing and new passengers. We pay attention to the following aspects:
– Passenger volumes.
– Travel times, where the following distinction can be made:
o in-vehicle time;
o waiting time at the first stop;
o transfer walking time;
o transfer waiting time.
– Number of transfers.
– Network flows / crowding in vehicles.
– Reliability: travel time variance on the journey level.
– Accessibility: number of inhabitants and jobs reachable within a travel time budget.

Data sources for the study are GTFS timetable data (open source), Smart card data (both from within the city of Amsterdam as for the regional feeder bus services) and Automated Vehicle Location data. To measure perceived quality of the PT network, a survey is conducted among inhabitants of Amsterdam. In this survey approximately 3.800 respondents were asked about the travel time perceptions of their last PT trip, both before and after opening of the metro line. Finally, for a sample of travellers the entire trip is followed by a GPS tracking app.

Impact analysis of a new metro line in Amsterdam using automated data sources

A new metro line (the north-south line) was opened in Amsterdam in July 2018, adding significant capacity to the existing urban public transport network consisting of bus, tram and metro modes. The opening of the metro line was accompanied by changes to the existing bus and tram network, such as removal of duplicate routes and addition of feeder routes.

Traditionally, the impact of such a network change was measured either ex-ante or post-op based on surveys or model forecasts (Vuk 2005; Knowles 1996; Engebretsen, Christiansen, and Strand 2017). However, with the availability of automated data sources such as the smart card data, the exact impact on transit demand and service quality can now be measured. However, so far this has been limited to analysing the changes in travel times and reliability at a trip level (Fu and Gu 2018), excluding transfers.
This research utilises smart card and AVL data to study the impact of the new line on travel patterns (passenger flows), travel times and reliability from a passenger perspective by considering journeys including transfers. The metrics are calculated at a stop-cluster level, enabling also a distributional analysis of the impacts. Such a post-op analysis of any policy intervention or network change could be used to refine the demand predictive ex-ante tools.

Check the Transit Data workshop contributions of Malvika Dixit: Presentation and Extended abstract

Combining Speed Adjustment and Holding Control for Regularity based Transit Operations

Vehicle bunching often occurs in high-frequency transit systems leading to deterioration of service reliability. It is thus necessary to control vehicles during operations. Holding control is a common solution for this situation, but it may result in longer vehicle running times. Speed adjustments can contribute to more regular operations while preventing prolonged trip times. This paper proposes a control strategy, which combines these two strategies to maintain the regularity of transit operations. The findings based on simulation study for trunk bus services in the Netherlands suggest that combining the two strategies implies both the positive and negative attributes of each control.

Find the MT-ITS presentation and paper of Aishah Imram HERE and HERE

Impacts of charging methods and mechanisms of zero emission buses on costs and level of service

To limit global warming and strive for more liveable and sustainable cities, innovative zero-emission (ZE) buses are on the rise all around the world. Different alternative vehicle propulsion methods have been introduced during the last decades. However, for now, only trolley, battery and fuel-cell electric vehicles can be classified as (on the pipe) ZE-buses.

This research focuses on battery electric buses, since they are most cost-efficient and – therefore – the most promising option for the (near) future. An important limitation of battery electric buses is however the limited range of operations due to capacity restrictions of batteries. Batteries should be (re)charged before, during and/or after daily operations.

Different charging methods, including different charging power systems are available to charge battery electric vehicles. As far as known to the authors, scientific literature focusing on the operations and charging scheduling of electric buses is scarce. In this study, a comparison of different applied charging methods for electric buses is obtained.
A ZE-bus station simulation method is developed to assess charging methods and charging regulations with regards to their impacts on a variety of costs and level of service indicators. This simulation-based method is multi applicable, since it is particularly based on general automated vehicle location (AVL) data. To demonstrate our model, a case study at Schiphol (Amsterdam Airport) is performed.
This research concludes that the shift to ZE-bus transit is involved with higher costs and passenger disturbances. Investment costs of ZE-buses increase substantially: Most electric vehicles are around 60 to 80 percent more expensive than conventional diesel engine vehicles and additional charging infrastructure investments are required. Benefits of electric operations, including vehicle propulsion cost savings up to 70 percent, are not able to compensate these high investments.
The charging method choice contain trade-offs between level of service and (vehicle and charging infrastructure) investment costs. (Slow) depot charging offers opportunities for operations on short distance lines. However, additional vehicles are required in order to replace a vehicle which should be recharged. In this respect, conventional timetables could be complied and the level of service remains unchanged.

To prevent fleet overcapacity, vehicles should be recharged fast (with high charging power) along the line. Slight charging related delays could occur, especially when the number of charging systems is not sufficient, and/or the charging times are relatively long. Bus end stations and terminals are suitable as fast charging locations, since charging time could be combined with buffer time there.

Finally, dynamic/in-motion charging offers opportunities to prevent charging related delays completely due to combined charging and operation time. This charging method is still in its infancy stage yet, so focus is more on (innovative) static charging methods now.

Find the MT-ITS presentation wih Max Wiercx and Raymond Huisman: HERE

Light rail lessons learnt worldwide

Light rail has several potential benefits, both from a mobility and urban quality perspective. However, not all light rail systems are a success and there is much debate about the costs. Niels van Oort, co-director of the Smart Public Transport Lab at TU Delft, investigated 61 cases worldwide and will share his findings on the wider benefits of light rail.

Find the presentation of the Spårvägsforum 2019 in Uppsala HERE

Passenger Travel Time Reliability for Multi-Modal Public Transport Journeys

Urban transit networks typically consist of multiple modes and the journeys may involve a transfer within or across modes. Hence, the passenger experience of travel time reliability is based on the whole journey experience including the transfers. Although the impact of transfers on reliability has been highlighted in the literature, the existing indicators either focus on uni-modal transfers only or fail to include all components of travel time in reliability measurement. This study extends the existing ‘Reliability Buffer Time’ metric to journeys with multi-modal transfers and develops a methodology to calculate it using a combination of smartcard and automatic vehicle location data. The developed methodology is applied to a real-life case study for the Amsterdam transit network consisting of bus, metro and tram services. By using a consistent method for all journeys in the network, reliability can be compared between different modes or between multiple routes for the same origin-destination pair. The developed metric can be used to study the reliability impacts of policies affecting multiple modes. It can also be used as an input to behavioral models such as mode, route or departure time choice models.

Find the TRB paper and presentation of Malvika Dixit HERE and HERE

Operations of zero-emission buses: impacts of charging methods and mechanisms on costs and the level of service

To limit global warming and strive for more liveable and sustainable cities, innovative zero-emission buses are on the rise all around the world. For now, only trolley, battery and fuel-cell electric vehicles can be classified as (on the pipe) zero-emission vehicles. Different charging methods, including different charging systems and power, are available to charge battery electric vehicles. However, scientific literature focused on the operation and charging scheduling of electric vehicles is scarce.
In this study, a comparison of different applied charging methods for electric buses is obtained. A new ZE-bus station simulation method is developed to assess charging methods and charging regulations with regard to their impacts on costs and level of service.
The shift to zero emission bus transport is meant for achieving more sustainable and liveable cities. However, this research concludes that this is involved with higher costs and passenger disturbances. The investment costs increase substantially. Benefits of electric operations, including vehicle propulsion cost savings up to 70 percent, are not able to compensate these high investments. (Slow) depot charging offers opportunities for operations on short distance lines. The depot location should be close to a bus station and additional fleet is required. In order to prevent fleet overcapacity, vehicles should be recharged with high charging power along the line, preferably at combined bus stations and terminals in order to prevent charging related delays. Dynamic/In-motion charging – still in its infancy stage yet – offers opportunities to prevent these delays due to combined charging and operation time.

Find the TRB paper and poster of Max Wiercx HERE and HERE

Robust Control for Regulating Frequent Bus Services: Supporting the Implementation of Headway-based Holding Strategies

Reliability is a key determinant of the quality of a transit service. Control is needed in order to deal with the stochastic nature of high-frequency bus services and to improve service reliability. In this study, we focus on holding control, both schedule- and headway-based strategies. An assessment framework is developed to systematically assess the effect of different strategies on passengers, the operator and transport authority. This framework can be applied by operators and authorities in order to determine what holding strategy is most beneficial to regulate headways, and thus solve related problems. In this research knowledge is gained about what service characteristics affect the performance of holding strategies and the robustness of these strategies in disrupted situations, by using scenarios. The framework is applied to a case study of a high-frequency regional bus line in the Netherlands. Based on the simulation results, we identified the line characteristics that are important for the performance of schedule- and headway-based strategies and determined how robust different strategies are in case of disruptions. Headway-based control strategies better mitigate irregularity along the line, especially when there are disruptions. However, schedule-based control strategies are currently easier to implement, because it does not require large changes in practice, and the performance of both strategies is generally equal in regular, undisrupted situations. In this paper, insights into what the concerns are for operators with respect to technical adaptations, logistical changes and behavioral aspects when using a headway-based strategy are given.

Find the TRB paper and presentation of Ellen van der Werff HERE and HERE

Improving railway passengers experience: two perspectives

This paper describes two perspectives to improve the passenger experience. The passenger satisfaction pyramid is introduced, consisting of the base of the pyramid (dissatisfiers) focusing on time well saved and the top of the pyramid (satisfiers) aiming at time well spent. The challenge in planning and design of public transport services is to find the most efficient (set of) design choices. Depending on the context this might either mean focusing on the top or on the bottom of the pyramid. We found that influencing and enhancing the qualities of the satisfiers is far more important than traditional studies showed us. For stations, regression analyses show that dissatisfiers are responsible for explaining almost half of the total score of the station and satisfiers are responsible for the other half of the scores passengers give for the station. We still have to put a lot of energy in getting the basics right, starting in the planning phase, but then we are not allowed to lean back. We have to keep investing in qualities like ambience, comfort and experience which makes the customers truly happy at the end of the day.

Read our paper HERE and find the presentation HERE

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