Demand Responsive Transport Services Research Articles

Preferences toward Bus Alternatives in Rural Areas of the Netherlands: A Stated Choice Experiment

Public transport in rural areas is under pressure because demand is low and dispersed. To reduce costs, flexible and on-demand services are often proposed as alternatives for conventional bus services. Conventional services are generally not suitable for rural areas, because the demand is low and dispersed. In this paper, a stated preference survey is designed to identify the preferences of rural bus users for alternative services. Other than the traditional bus, two other modes are included in this study: a demand responsive transport (DRT) service and an express bus service with bike-sharing services for last mile transport. Given the on-demand nature of these alternatives, flexibility- and reliability-related attributes are included in the stated preference survey. The results from the choice model indicate that the reliability and flexibility aspects do not have a large effect on the preference for the on-demand alternatives. Instead, cost, access and egress times, and in-vehicle time play a bigger role in individuals’ preferences toward the different alternatives. A sensitivity analysis shows that changes in the operational characteristics can make the on-demand alternatives more attractive. However, many bus users still prefer the conventional bus service over the on-demand alternatives.

Mobility service design via joint optimization of transit networks and demand-responsive services

This paper proposes a modeling framework to design an integrated mobility service system that is composed of a local demand-responsive transportation (DRT) component and a fixed-route transit network component. The region is partitioned into disjoint local zones, and a trip is characterized into an intra- or inter-zonal one based on whether its origin and destination belong to the same zone. The transit network provides backbone line-haul service to inter-zonal trips, while the DRT system targets intra-zonal trips as well as the first-mile and last-mile legs of inter-zonal trips. The system components can be broadly defined, and this paper considers, as examples, conventional non-shared taxi or ride-sharing for the DRT service, and regular bus, bus rapid transit (BRT), or metro for the backbone network. For quantitative analysis of the DRT services, new aspatial queuing network models are developed to capture various DRT operations for serving trips with randomly distributed origins and destinations (i.e., intra-zonal trips) and those with origins or destinations concentrated at a set of fixed transit stations (i.e., first- or last-mile trip legs) at the same time. Each queuing model is integrated with the transit network design model, through proper service region partition, to derive closed-form formulas for the agency and passenger costs. Then, we formulate constrained non-linear programs that simultaneously optimize the zone partition, the fleet size and repositioning operation for the local DRT service, as well as the spacing and headway of a grid transit network. We apply the proposed models to a variety of transit technologies and application scenarios, so as to demonstrate applicability of the models, and to show promising performance of the proposed systems.

Public Transit Planning and Operation in the Era of Automation, Electrification, and Personalization

The advent of Connected and Autonomous Vehicles (CAVs) and Mobile Internet technologies is reshaping the public transport sector. Autonomous buses are equipped with varying advanced sensors, and hold great promises to enhancing the responsiveness and flexibility of public transit system. In the context of CAVs, transit operators can not only optimize service headway but also adjust bus capacity to meet the time-varying passenger demand. Anticipated benefits of introducing autonomous buses to the existing transit systems include safety improvement, driver cost reduction, and optimal routing. Bus electrification is another global trend to replace traditional diesel buses for energy savings. Electric buses are advantageous to both operators and passengers due to low greenhouse gas emission, maintenance cost, as well as noise pollution. In recent years, demand responsive public transport (DRPT) services (e.g. customized bus, microtransit) receive huge success thanks to the development of Mobile Internet. Unlike traditional bus services or the fixed-route transit service that relies on passive recipients, fixed stops, and schedules, DRPT can provide personalized service for specific clients through interactive information platform (Internet or smartphone). The aforementioned new types of public transit services significantly improve service quality, reduce energy consumption, and ultimately attract more ridership. To fully explore the benefits of personalized, electric and autonomous transit systems, new analytical models and data-driven methods for transit planning and operation are needed. The authors have selected 15 articles for review in this special issue. A summary of these articles is outlined below.

A multi objective approach for DRT service using tabu search

Urban population is increasing fast. This is creating new challenges to public transport systems since some groups of citizens as elderly people may have sensory, cognitive or motor impairments that need to be addressed. This work explores the potential of a Demand Responsive Transport (DRT) system for people with reduced mobility in an urban environment. For this purpose, the Dial-A-Ride Problem (DARP) was implemented using a multivariable minimisation approach. In this approach, an Assigning Request to Vehicles (ARV) algorithm is used to obtain an initial solution. Then a Multi-Objective Tabu Search Algorithm (MOTSA) is applied to the initial solution to search for the non-dominated solution (optimisation phase). In this optimisation phase, the total travelled distance, the deadheading distance and the number of vehicles were minimised. The performance of the model was computed combining different parameters’ values of the number of requests, boarding time for each user, the number of seats in each vehicle, vehicle’s speed, the total number of iterations, and candidate threshold number (the algorithm’s parameter). The computational results found a strong positive correlation between the number of requests and the: total travelled distance (rs = 0.977, p-value<0.001) and the number of vehicles (rs =0.883, p-value<0.001); and a low positive correlation between the number of requests and the optimised total travelled distance (rs =0.331, p-value<0.001) and the optimised number of vehicles (rs =0.340, p-value<0.001).

Travelers’ Attitudes Toward Mobile Application–Based Public Transport Services in Lahore

Many cities in developing countries are facing challenges of providing quality public transport facilities to the public. The demand-responsive transport (DRT) initiatives in some cities have helped in providing transportation alternatives to the travelers, and in filling the gap between demand and supply. Recently introduced DRT initiatives in Lahore included the mobile app-based Airlift and Swvl bus services. This article is aimed at evaluating the travelers’ attitudes toward mobile application (app)–based DRT services in Lahore with the help of a questionnaire survey. A questionnaire was designed consisting of travelers’ personal and travel information and their perceptions on selected attributes of Airlift and Swvl bus services. A total of 440 samples were collected through interviews. An exploratory factor analysis (EFA) revealed three factors of service quality, that is, Accessibility and Scheduling Attributes (ASA), Instrumental Attributes (IA), and Service Attraction Attributes (SAA). The results of Structural Equation Modeling (SEM) showed that the ASA, IA, and SAA are significant determinants of travelers’ attitudes toward the existence of Airlift and Swvl bus services in Lahore. These factors have strong correlations with travelers’ intentions to use Airlift and Swvl services in the future. The waiting time at a stop, travelers’ income, vehicle ownership, trip purpose, and profession are also significant in determining the travelers’ attitudes and preferences with app-based public transport services. These findings would be helpful for the service providers and transport planners for making appropriate policies to improve the quality of these services.

Evaluation methods and governance practices of new flexible passenger transport projects

The emergence of new flexible passenger transport services enabled by technological advancements can have substantial impacts on efficiency and sustainability of public transport systems. Socio-economic appraisal methods of transport investments have developed during last decades, and especially CBA is proven to provide robust method for ranking alternative large conventional transport investments such as rail and road projects. However, there is much more uncertainty with potential impacts of new flexible passenger transport serves such as the automated demand responsive transport services, which can be seen as disruptive technologies on the transport markets. For addressing this uncertainty, we studied governance practices for using CBA and other economic appraisal methods in public decision making in the European Union with a special focus on Germany. We identified and analysed the most uncertain and challenging impacts of the new flexible transport services, which require better consideration in current evaluation methods and practices. The results point out challenges and opportunities for reaching the gap between current appraisal practices and the latest knowledge on the potential impacts of new flexible passenger transport services.

How much flexibility does rural public transport need? – Implications from a fully flexible DRT system

Rural regions in industrialised countries are facing problems in public transport (PT) provision against the backdrop of demographic change, urbanisation and austerity policies. However, innovative mobility concepts evolve under technological developments. Demand responsive transport (DRT) has been identified in research to meet the challenges and efficiently improve mobility through the concept of ride-pooling. Still, most of these DRT services are being investigated in urban settings with high mobility demand and population density. Research on low-demand regions, such as the Oberharz in Germany, is rarely considered. Moreover, the applied DRT services come with several restrictions regarding stop locations, customer target groups or spatial restrictions. Therefore, this paper fills this gap through spatial and temporal analysis of a real-life, fully flexible and true door-to-door DRT experiment. Over a 6-months period around 38,000 trips took place in the Oberharz. The analysis of these trips shows that an unrestricted DRT service between three main centres (Goslar, Clausthal-Zellerfeld and Osterode) results in main travel axes between these cities while the more remote areas forfeit mobility to these centres of public service provision. Consequently, a feeder-trunk system should be favoured for future DRT services in low-demand areas to sustainably improve mobility in remote regions. The complementary extension of the existing PT through such a DRT service should then meet mobility needs of rural areas to redeem car dependency and improve mobility for all population groups.

Transport industry adapting to change: An Australian case study

Growing governmental reluctance to fund local bus services is leading to increased interest in demand responsive transport (DRT). At the same time, the use of technology to facilitate access to DRT is creating circumstances for significant disruption of the way bus services are planned, contracted, delivered and regulated. This disruption creates uncertainty for bus operators but also presents an opportunity for operators to proactively adapt to better meet passenger needs and capture more of the market. This could involve diversifying their businesses, becoming total local transport providers and/or brokers, along Mobility-as-a-Service (MaaS) type lines, where the passenger is of central importance, rather than the mode of transport. The paper presents a Victorian case study that explores how the bus industry's voluntary professional association is working with its members to augment their capabilities and deliver DRT services, against the background of a changing contractual environment for delivery of services. The provision of a new transport business model, and the technological platform that supports it via their voluntary professional association, will enable bus operators to compete in the growing DRT realm and passenger services levels to improve, also supporting better social and environmental outcomes.

Determining the Market Uptake of Demand Responsive Transport Enabled Public Transport Service

Demand responsive transport (DRT) alternatives offer improved mobility to travellers through station-to-destination or door-to-transit operations. In particular, door-to-transit DRT service acts as a feeder to major public transport hubs, making public transport more accessible and attractive to travellers. This work aims to study the mode choice behaviour of travellers between their current modes and a new service, which is a combination of DRT and public transport. The study is conducted in the Northern Beaches area of Sydney, Australia where DRT is expected to serve as a feeder to the newly introduced express bus service called B-Line. A stated preference (SP) experiment is designed where multiple-choice scenarios involving two modes, status quo (SQ) and the new service (combined DRT and public transit), are presented to the participants. The survey uses trip specific information obtained from Google API to form the attributes for the new service. The collected data are analysed using a latent class choice model (LCCM), which segments the observed sample into distinct groups where each group has its own taste and preferences towards the new service option. Results from the study reveal that one of the identified user segments shows 96 percent uptake towards the new service option, while the other user segment shows an uptake of 44 percent. Results also show that individuals making work trips are more likely to opt for the new service. Findings from this study can provide information to urban planners regarding the market uptake of DRT services. Furthermore, the findings can also help planners in implementing segment specific policies aimed at further improving uptake towards DRT along with public transport.

What are the determinants of the willingness to share rides in pooled on-demand services?

Simulation studies suggest that pooled on-demand services (also referred to as Demand Responsive Transport, ridesharing, shared ride-hailing or shared ridesourcing services) have the potential to bring large benefits to urban areas while inducing limited time losses for their users. However, in reality, the large majority of users request individual rides (and not pooled rides) in existing on-demand services, leading to increases in motorised vehicle miles travelled. In this study, we investigate to what extent fare discounts, additional travel time, and the (un)willingness to share the ride with (different numbers of) other passengers play a role in the decision of individuals to share rides. To this end, we design a stated preference study targeting Dutch urban individuals. In our research, we (1) disentangle the sharing aspect from related time–cost trade-offs (e.g. detours), (2) investigate preference heterogeneity regarding the studied attributes and identify distinct market segments, and (3) simulate scenarios to understand the impact of the obtained parameters in the breakdown between individual and pooled services. We find that less than one third of respondents have strong preferences against sharing their rides. Also, we find that different market segments vary not only in their values of the willingness to share, but also in how they perceive this willingness to share (per-ride or proportional to the in-vehicle time). Further, the scenario analysis demonstrates that the share of individuals who are willing to share rides depends primarily on the time–cost trade-offs, rather than on the disutility stemming from pooling rides per se.

Demand Responsive Transport Service of ‘Dead-End Villages’ in Interurban Traffic

Providing a sustainable public transport service for areas with several small villages or hamlets is a challenge for the whole of Europe. To serve ‘dead-end villages’, vehicles must make a to-and-fro detour to each village, which requires considerable performance from the operator, and the service must also be ordered from the responsible bodies. The number of inhabitants in rural areas is constantly decreasing, and the remaining residents are aging. This process is due to the fact that economically active people in the country tend to move into towns offering jobs and public institutions instead of commuting to work. The performance requirement of serving low transport demand areas like ‘dead-end villages’ is high, while the number of passengers is very low. Furthermore, passengers are economically less active, and thus their transport must largely be subsidized. The present study hypothesizes that replacing traditional public transport with demand responsive transport (DRT) can make the service of rural areas with less public transport service and low demand sustainable. To prove this hypothesis, a generally applicable, innovative method of analysis based on performance–allocation is introduced, and the application of this method is illustrated by a case study conducted in northeastern Hungary. The number of ‘dead-end villages’ is high in the surveyed area; consequently, the results are impressive. The mathematical model applied here uses several parameters (e.g., population, traffic surveys, trip distance, operational costs), thus the analysis is highly complex.

The technology behind a shared demand responsive transport system for a university campus

Shared Demand Responsive Transport (DRT) services are flexible services increasingly regarded as one of the solutions able to respond to changing mobility demands. Research provides ample evidence from a number of case studies, as well as technological innovations that support such services. Previous research conducted in Malta showed how shared DRT services would be able to provide a mid-market alternative to the private car. Concerns however were raised about the extent of the service area and the resulting travel time. This study looks at focusing the services around a university campus situated within the urban agglomeration on the island of Malta. The University of Malta is the state funded higher education institution and has a population of 15,000 people between students and staff, similar in size to any large town in the islands. Complex travel patterns, aggregated in a relatively small area, and restrictions on provision of car parking provide an opportunity for the team to develop the technology for a DRT system which is tailor-made to the mobility needs of the University. This paper provides the motivation and background to the case study and describes the development of the technology. Field trials carried out around campus are presented using key service level parameters. The study found that the cost of service is approximately double the cost of local buses. Further engagement with local private and public stakeholders support the discussion on the way forward for the technology and implementation. Overall the project demonstrates that ICT enabled DRT systems are feasible from both a technological and business point of view, where trading off quality of service with cost. Such systems promise to deliver mobility solutions that support the deployment of green solutions for sustainable campuses.

Analytical models for comparing Demand Responsive Transport with bus services in low demand interurban areas

ABSTRACT As new shared mobility services emerge there is an increasing need for better understanding of the role and potential markets of these services which would result in viable business models. The current research aims at exploring Demand Responsive Transport (DRT) services, as a case of efficient mobility service provision for low demand interurban areas. Analytical models are developed and applied in a real case identifying critical demand thresholds for the alternative modes. Finally, the analysis points out the trade-offs between costs and level of service a transport operator or mobility provider needs to consider to implement a successful service.

Assessment of the DRT System Based on an Optimal Routing Strategy

Demand responsive transport (DRT) is operated according to flexible routes, dispatch intervals, and dynamic demand, is attracting a lot of attention. The biggest characteristic of the DRT service is that the vehicle routes and schedules are operated optimally based on real-time travel requests of using passengers without fixed operating schedules. This study analyzed the feasibility of implementing the DRT service by analyzing the benefits for the users and cost of the operator from the effects of increasing public transportation use and providing personalized mobility service based on DRT implementation by the introduction of DRT using multi-agent transport simulation (MATSim). Through the simulation, the DRT is expected to provide convenient, fast, and cost-effective mobility services to customers; provide an optimal vehicle scale to providers; and, ultimately, achieve a safe and efficient transportation system.

A metaheuristic for evaluation of an integrated special transport service

ABSTRACT This work concerns evaluation of integrated demand responsive services, in which certain parts of the passengers’ door-to-door journeys are served by fixed route public transport. The purpose of combining a special transport service with a fixed route service is to reduce the high, publicly subsidized, operational costs of the special transport service. To be able to recommend in which situations, or areas, it is beneficial to use an integrated service we present a metaheuristic for solving the routing problem in such a service. The metaheuristic can be implemented as part of an evaluation tool for policy makers and officials, providing insights into the effects of an integrated demand responsive service compared to a non-integrated. The metaheuristic is based on the adaptive large neighbourhood search (ALNS) framework. It is applied to a data set from a real-world, rural, demand responsive special transport service and the fixed route service available in the area. The objective used in our heuristic is to minimize the distance driven by the demand responsive vehicles. The distance driven is strongly related to the operational cost of the service. Our tests show that the distance driven by the demand responsive vehicles is reduced by 16%, giving a substantial cost reduction for the special transport service in the given area. Highlights Evaluation of integrated demand responsive service Combining special transport with a fixed route service to reduce operational costs Metaheuristic, based on the adaptive large neighbourhood search (ALNS) framework Comparing integrated service to non-integrated

Proactive empty vehicle rebalancing for Demand Responsive Transport services

Abstract Worldwide, ridesharing business is steadily growing and has started to receive attention also by public transport operators. With future fleets of Autonomous Vehicles, new business models connecting schedule-based public transport and feeder fleets might become a feasible transport mode. However, such fleets require a good management to warrant a high level of service. One of the key aspects of this is proactive vehicle rebalancing based on the expected demand for trips. In this paper we model vehicle rebalancing as the Dynamic Transportation Problem. Results suggest that waiting times can be cut by around 30 % without increasing the overall vehicle miles travelled for a feeder fleet in rural Switzerland.

A general model of demand-responsive transportation services: From taxi to ridesharing to dial-a-ride

The paper presents a general analytic framework to model transit systems that provide door-to-door service. The model includes as special cases non-shared taxi and demand responsive transportation (DRT). In the latter we include both, paratransit services such as dial-a-ride (DAR), and the form of ridesharing (shared taxi) currently being used by crowd-sourced taxi companies like Lyft and Uber. The framework yields somewhat optimistic results because, among other things, it is deterministic and does not track vehicles across space. By virtue of its simplicity, however, the framework yields approximate closed form formulas for many cases of interest.

The Dutch elderly's preferences toward a smart demand-responsive transport service

The ageing of the population poses mobility-related challenges worldwide. The emergence of new transport services that utilise technological innovations allows for new, more convenient ways to provide demand-responsive transport services in areas with limited or no regular public transport service. The question is how the features of these new services are preferred by all age groups, in particular, those with limited mobility, such as the elderly.In this study, we evaluate the preference of the elderly toward Breng flex, a smart Demand Responsive Transport (DRT) service offered in two adjacent Dutch cities and their surroundings. We combine results from expert interviews (n = 4), a face-to-face survey with elderly non-users of Breng flex (n = 38), and an online survey of Breng flex users of all ages (n = 958). The results illustrate fourteen features of smart forms of DRT that are preferred by the elderly, three of which are identified here for the first time. We discuss the trade-off between various features for the case study area and make suggestions regarding the design of a mobility service that can improve accessibility of the elderly.

Multi-agent simulation for planning and designing new shared mobility services

Limiting private cars' use while promoting sustainable modes of transport is one of the main challenges of urban transport planning. In this context, characterized by scarce resources and increasing demand for mobility, Demand Responsive Shared Transport (DRST) services can bridge the gap between shared low-quality public transport and unsustainable individual private transport. Taking advantage of Information and Communication Technologies (ICT), they can supply transport solutions ranging from flexible transit to ride sharing services, providing real-time “on demand” mobility through fleets of vehicles shared by different passengers. The optimal design of a DRST service requires a trade-off among efficiency (from the operators' point of view), service quality (from the users' point of view) and sustainability (from the community's point of view). In this paper, an agent-based model (ABM) fed with GIS data is used to explore different system configurations of a specific type of DRST service, i.e. flexible transit, and to estimate the transport demand and supply variables that make the service feasible and convenient. The model reproduces a mixed fixed/flexible route transit service with different fleet size and vehicle capacity in the city of Ragusa (Italy) with the aim to: (i) make a first test of the ABM model with GIS-based demand and road network models; (ii) explore different vehicle dispatching strategies; (iii) find appropriate indicators to monitor the service quality and efficiency. Simulation results show the impact of fleet composition and route choice strategy on the system performance. In particular, they show an optimal range of operating vehicles that minimizes a total unit cost indicator, accounting both for passenger travel time and vehicle operation cost. By reproducing the microinteraction between demand and supply agents (i.e. passengers and vehicles), it is possible to monitor the macroscopic behaviour of the system, and derive useful suggestions for the correct planning, management and optimization of DRST services.

Exploring the distances people walk to access public transport

ABSTRACTA shift from private motorised transport to more active transportation can, among other things, deliver significant health benefits. The main disadvantage of active transport (in particular walking) for most people compared to private motorised transport is the limited range. Public transport (PT) can complement the use of active modes and extend their range. Therefore, there might be potential to increase physical activity through an increase in PT use. This article takes a closer look at how walking relates to the use of PT by examining existing literature on the topic. It aims to study how far people walk to and from PT and what key factors influence this. Scopus, Transport Research International Documentation and Web of Science have been searched systematically for relevant articles, conference papers and books. After screening of titles and abstracts, 41 relevant publications were identified. Studies were included if they quantified the amount of walking (measured as either distance or time) that is directly related to the use of PT. Studies that quantified walking using general measures of daily physical activity or daily walking or that used stated preference designs were excluded. The PT systems considered in this paper are mass transport systems in urban areas, either road- or rail-based, with fixed schedules and stops. Demand responsive transport services, which can offer door-to-door travel, are not considered, as these systems can to a large extent eliminate the need to walk. In the identified publications, a large variety of walking distances and times have been reported, and these seem to be highly context-specific. The paper establishes the evidence for the wide range of factors that influence walking related to PT, which have been categorised as personal, PT-related, environmental, and journey-related. The different methods that have been used are discussed by critically analysing their advantages and limitations. Only a limited number of these methods used allow for an accurate assessment of the walking distances to and from PT. The paper concludes with suggestions for future research, such as a need for more accurate measurement of walking and research in different geographical areas to shed light on underlying influences of culture and climate.