Demand Responsive Transport Research Articles

Urban Size and Density Condition for the Introduction of Demand Responsive Transport

近年、モータリゼーションの進行や郊外型の都市構造への変化によって、自治体の運行するコミュニティバスなどの利用人数が減少している。そのため、バスに代わる交通手段として、多くの地域でデマンド型交通が導入されている。本研究では、デマンド型交通の成立条件の理論的考察を目的として、全国のデマンド型交通導入自治体の把握とその統計分析、並びに需要密度の変化と運行経路・ダイヤ柔軟性の異なる3つの交通手段の成立可能性について、需要側・供給側双方のコストの観点からデマンド型交通の成立条件に関する基礎的条件を導出し、現実の導入地域との値の比較を行う。分析の結果、デマンド型交通の導入地域の特徴として、都市の面積が大きく人口密度の低い、乗合バスの利用分担率が低く自家用車の分担率が高い地域で導入されている傾向を確認した。また、都市モデルを用いた理論的検討から、適切な利用人数を維持できる小規模都市でのデマンド型交通の有効性と、面積の広い自治体での導入の困難性を示した。さらに、モデルから得られたデマンド型交通の有利領域と全国の導入自治体の都市規模・需要密度の比較を行い、人口低密地域におけるモデルの適合性を確認した。

Integrated approach towards sustainable development

Public transport systems, both rail and road, have over previous years developed relatively independent of each other and in competition with the private car. In recent years the changes in demand for public transport due to increase in car ownership, changes in land use and wider economic forces have highlighted the importance of integrating existing networks as an alternative to mass development of new transport systems. At the same time, citizens are becoming more demanding. This multi-faceted challenge can only be addressed by adopting an integrated approach to mobility issues with the support of all protagonists. This approach must be based on twin foundations: on the one hand, the coordination of urban policies with journey policies, and, on the other hand, modal integration between transport networks. The integration of different modes including non-motorised transport (NMT) with public transport services is essential for sustainable development and is a real challenge for transport planners. In view of the above the overall concepts of system integration, issues related to integration of NMT services with public transport modes, more effective operations of demand responsive transport (DRT) over conventional bus services in the present scenario, improvement of network characteristics due to integration of modes, etc. have been discussed in this paper. Various policies, issues, challenges and problems to be faced for integrated urban mass transportation system planning towards sustainable development are presented in this paper.

Role of automatic vehicle location systems and localisation accuracy in freight transport: an analytical estimation of gained operational times

This study concerns the application of automatic vehicle location systems (AVLSs) for the control and management of fleet of vehicles whose regular routes are random, that is, with origins and destinations so numerous and variable that they cannot be predefined. Typical examples include road shipments, pick-up and delivery services and express couriers, demand responsive transport services and public utility services (gas, water etc.). Specific reference is made to transport of goods but analogous observations may be valid for passenger transport. The average response time of the mobile unit depends on (i) the accuracy of the AVLS adopted; (ii) the configuration of the fleet within the territory where it operates; (iii) a number of operative parameters, among which are the size of the operative area, the number of vehicles employed, the average time that they are in use, their average speed and the average time taken to perform the service. The results of two specific models provide average response times which can be compared in transport operations carried out with and without the use of an AVLS. If we abstract the equations derived from these, we obtain a quantity Δt, which measures the reduction in response time resulting from the adoption of an AVLS. The relevance of the results is related to the role of accuracy, integrity and continuity of the future Galileo system for transport location services.

From mode choice to modal diversion: A new behavioural paradigm and an application to the study of the demand for innovative transport services

We analyse past research efforts that focus on modal diversion in the transport sector, as opposed to the classical mode choice concept, showing the added value of this alternative framework that emerges from the existing scientific literature. The modal diversion paradigm is then used to assess the relative importance of the technical performances of transport services on one hand and of the subjective factors of its potential users on the other, when forecasting the use of a new means among a group of white-collars working in a French research institute. We quantitatively show that multimodal habits and cognitive attitudes have an importance that is in general not negligible for this group, compared to that of the transport services performances, even if only these latter are routinely considered by engineers and planners. Beyond this, we find that the role of self-related factors further increased when the group was less familiar with the technological background and the subsequent operation of the new system, such as in the case of demand responsive transport services.

Using GIS to visualise and evaluate student travel behaviour

Using GIS to evaluate travel behaviour is an important technique to increase our understanding of the relationship between accessibility and transport demand. In this paper, the activity space concept was used to identify the nature of participation in activities (or lack of it) amongst a group of students using a 2 day travel–activity diary. Three different indicators such as the number of unique locations visited, average daily distance travelled, and average daily activity duration were used to measure the size of activity spaces. These indicators reflect levels of accessibility, personal mobility, and the extent of participation, respectively. Multiple regression analyses were used to assess the impacts of students socio-economic status and the spatial characteristics of home location. Although no differences were found in the levels of accessibility and the extent of participation measures, home location with respect to a demand responsive transport (DRT) service was found to be the most important determinant of their mobility patterns. Despite being able to travel longer distances, students who live outside of the DRT service area were found to be temporally excluded from some opportunities. Student activity spaces were also visualised within a GIS environment and a spatial analysis was conducted to underpin the evaluation of the performance of the DRT. This approach was also used to identify the activity spaces of individuals that are geographically excluded from the service. Evaluation of these results indicated that although the service currently covers areas of high demand, 90% of the activity spaces remained un-served by the DRT service. Using this data six new routes were designed to meet the coverage goal of public transport based on a measure of network impedance based on inverse activity density. Following assessment of public transport service coverage, the study was extended using a spatial multi criteria evaluation (SMCE) technique to assess the effect of service provision on patronage.

Reducing non-collision injuries in special transportation services by enhanced safety culture

Previous research has pointed out that non-collision injuries occur among wheelchair users in Special Transportation Services (STS – a demand-responsive transport mode). The organization of such modes is also quite complex, involving both stakeholders and key personnel at different levels. Our objective was therefore to qualitatively explore the state of safety, as perceived and discussed within a workplace context. Focus groups were held with drivers of both taxi companies and bus companies. The results indicated that passengers run the risk of being injured without being involved in a vehicle collision. The pertinent organizational and corporate culture did not prioritize safety. The drivers identified some relatively clear-cut safety threats, primarily before and after a ride, at vehicle standstill. The driver's work place seemed to be surrounded with a reactive instead of proactive structure. We conclude that not only vehicle and wheelchair technical safety must be considered in STS, but also system safety. Instead of viewing drivers’ error as a cause, it should be seen as a symptom of systems failure. Human error is connected to aspects of tools, tasks, and operating environment. Enhanced understanding and influence of these connections within STS and accessible public transport systems will promote safety for wheelchair users.

Older people and local public transit: Mobility effects of accessibility improvements in Sweden

Several transportation factors concerning older and disabled people are under transition in Sweden at present. By the year 2010, the public transit system must be fully accessible for all passengers. The present survey studied older people, in order to assess the perceived travel opportunities. Questionnaires were sent to a sample of older citizens (75+) in three Swedish mid-sized municipalities. The general conclusions were that even though older people show appreciation of the existing travel opportunities, there was evidence for restricted mobility for some sub-groups of these older people, due to various perceived barriers. These groups have few optional modes, and despite various accessibility measures, special transportation services – the mandatory demand-responsive transport service – continues to provide crucial mobility. Hence, there is more to be done regarding accessibility and usability in public transit for older people. Further studies have to clarify reasons for bus travel cessation. Even larger efforts have to be put into accessibility improvements, in particular intermediate transit solutions in order to meet the regulations and policies.

Flexible transport services: A new market opportunity for public transport

The term Demand-Responsive Transport (DRT) has been increasingly applied in the last 10 years to a niche market that replaces or feeds (usually via small low floor buses or taxis) conventional transport where demand is low and often spread over a large area. More recently, the concept of DRT as a niche market has been broadened to include a wider range of flexible, demand-responsive transport services and is increasingly referred to as Flexible Transport Services (FTSs). The contention of this paper is that well-implemented FTS has the potential to revitalise bus-based public transport services which are traditionally based on fixed networks with variable geographical coverage and levels of service.

Waiting strategies for the dynamic dial-a-ride problem

The dial-a-ride service is a form of demand responsive transport that delivers passenger requests from their specified origins to destinations with desired time windows. It is usually used as a mean to provide transport for people who are not able to access a private transportation conveniently, or as a transport policy to encourage share rides and reduce driving. In this study, the authors consider the dynamic problem, which receives real-time requests during the day of operation. In the scheduling of the services, there may exist waiting for vehicles along the route at stops. This paper proposes three waiting strategies, namely, drive first (DF), wait first (WF) and modified dynamic wait (MDW), to allocate this waiting time along the stops by holding the vehicles so as to minimise the cost in accepting future calls. Simulation experiments show that the MDW is superior to DF and WF.

Demand responsive urban public transport system design: Methodology and application

In this paper, we present a methodology for solving the Public Transport Network Design Problem (PTNDP) and describe its application in the context of the Design Study developed in order to propose a new structure for the transit system of the city of Santiago, Chile. Firstly, we briefly define the PTNDP as a multilevel programming problem and discuss the solution method implemented. Then, the application of this methodology to the Santiago transit system is presented, and the main results obtained are analyzed. The new restructured system, based on a hierarchy of specialized services that complement and coordinate their operations and using an integrated fare scheme, is compared with an optimized version (optimal frequencies) of the current one, a set of direct services, mainly based on the operation of independent itineraries, without fare integration. The most important conclusions are the following: (a) the private operating costs and the social costs of the restructured system, using higher standard buses, are considerably lower than the costs of the current system; (b) these cost reductions allow government authorities to introduce an important number of modernizing measures without subsidies and fare increases.

A methodological approach for developing and assessing business models for flexible transport systems

Flexible transport services include a wide range of demand responsive transport systems that provide non-conventional passenger and freight transportation services. Several alternative business models varying according to the local market conditions, the socio-economic, legal, and institutional framework may be developed for the provision of Flexible Transport Systems (FTS). The objective of this paper is twofold: first to present an integrated methodological framework for developing and assessing alternative FTS business models and second to demonstrate its applicability to a case study regarding the prioritization of alternative FTS business models for the provision of flexible passenger transport services in Helsinki.

Öffentliches Verkehrsangebot in ländlichen Räumen Gestaltungsmöglichkeiten und Auswirkungen auf die Lebensqualität

The accessibility of destinations in rural areas via public transport is generally poor, if possible at all. The lack of public transport deprives individuals, who cannot or do not want to use a private car, of a certain quality of life. The obligation of public transport to be cost efficient leads to further reductions in the service quality and to further decreases in the accessibility of friends and relatives, grocers, health services, education and recreation facilities. The European research project Actions on the integration of Rural Transport Services (ARTS) investigated innovative public transport solutions particularly in scarcely populated areas. Projects in eight European regions were implemented and evaluated, six of which resulted in demand responsive transport initiatives or public transport linked with school transport. The examples show that improvements in public transport can be achieved, but must be tailored to the local situation. For those without access to a car, being able to make trips by public transport is valued as important to their quality of life and helps to sustain social life in the rural areas.

Multi-agent Simulation for Evaluating Demand Responsive Transport System

Multi-agent Simulation for Evaluating Demand Responsive Transport System

Demand Responsive Transport and Its Capability in Addressing the Employment needs of Rural Areas

Demand Responsive Transport and Its Capability in Addressing the Employment needs of Rural Areas

農村地域におけるデマンド型交通の運行範囲の設定条件

The objective of this paper is to discuss regional transportation service reconstruction and methodologies for that as a solution for the issue of expanding areas without public transportation services in rural areas. This study surveyed two of Demand Responsive Transport Systems in rural area. It is important that the service level and coverage of DRT is decided according to the characteristic in the region, and cooperation with another existing bus.

The importance of information flows temporal attributes for the efficient scheduling of dynamic demand responsive transport services

AbstractThe operation of a demand responsive transport service usually involves the management of dynamic requests. The underlying algorithms are mainly adaptations of procedures carefully designed to solve static versions of the problem, in which all the requests are known in advance. However there is no guarantee that the effectiveness of an algorithm stays unchanged when it is manipulated to work in a dynamic environment. On the other hand, the way the input is revealed to the algorithm has a decisive role on the schedule quality. We analyze three characteristics of the information flow (percentage of real‐time requests, interval between call‐in and requested pickup time and length of the computational cycle time), assessing their influence on the effectiveness of the scheduling process.

Object modeling and path computation for multimodal travel systems

This paper describes a multimodal travel system (MTS) designed to address the needs of a variety of demand-responsive transport. An origin–destination ( O– D) trip in transportation network can be accomplished by using multiple modes. In urban network passengers may boarding buses or metros to go from one place to another, and modes as autobus or trains are used by passengers to travel between cities. The work focuses on the network object modeling and multimodal shortest path algorithm. A solution to the problem of long-run planning of transit on multimodal network has been implemented and tested. The work presents the general results found, and the proposed algorithm recognizes the set of constraints related to the time schedule and the sequence of used modes in a O– D trip. The aim is to provide a tool for detecting the facilities of using different travel modes through a transportation network. Routings may include distinct combination of rail, and route. Geographic Information Systems (GIS) were invaluable in the cost-effective construction and maintenance of this work and the subsequent validation of mode sequences and paths selections. Attention is devoted to the multimodal path operator as well as to the use of GIS-transit planning.

Applicability for Demand Responsive Transport Systems in Densely-populated Areas

Demand Responsive Transport systems (DRTs) will be effective for fewer demand cases, and adopt in low density areas in Japan recently. However, DRTs are also expected to adopt in urban areas especially for mobility handicapped people. In this paper, the authors introduced the Japanese experience of adopting DRTs in Urban Areas, and showed the group raised their mobility by DRTs. In addition, we indicate the suitable operation type of DRTs with considering the arrangement of Meeting Points and the demand of DRTs. Finally, we tried to consider the suitable number of users for adopting DRTs in densely-populated areas.

HYBRID GENETIC ALGORITHM TO APPROACH THE DARP IN A DEMAND RESPONSIVE PASSENGER SERVICE

In this work, we address a Demand Responsive Transport System capable of managing incoming transport demand using a solution architecture based on a two- stage algorithm to solve a Dial-a-Ride Problem instance. In the first stage, a constructive heuristic algorithm quickly provides a feasible solution to accept the incoming demand. The algorithm in the second stage is a specialized Hybrid Genetic Algorithm that attempts to improve the solution evaluated at the first stage by using the time between two consecutive transportation events.

A model for the fleet sizing of demand responsive transportation services with time windows

We study the problem of determining the number of vehicles needed to provide a demand responsive transit service with a predetermined quality for the user in terms of waiting time at the stops and maximum allowed detour. We propose a probabilistic model that requires only the knowledge of the distribution of the demand over the service area and the quality of the service in terms of time windows associated of pickup and delivery nodes. This methodology can be much more effective and straightforward compared to a simulation approach whenever detailed data on demand patterns are not available. Computational results under a fairly broad range of test problems show that our model can provide an estimation of the required size of the fleet in several different scenarios.