Conventional Public Transit Research Articles

A tale of two modes: Who will use single user and shared autonomous vehicles

The two most traditional and conventional transportation modes, private vehicles, and public transit, may be disrupted due to the advent of shared autonomous vehicles (SAVs), which can offer affordable on-demand mobility solutions leading to a transformed transportation system. However, little is known about the attributes affecting mode choice decisions and the impacts of the emergence of SAVs on travel behavior. A stated preference survey consisting of choice experiments, distributed online in October and November 2017 to residents of the Chicago-Naperville-Elgin, IL-IN-WI metropolitan statistical area, is used to determine the perceived impacts that SAVs may have on mode choice decisions and the corresponding value of travel time savings. Based on a representative sample (in terms of age and gender) of 400 responses, random parameter (mixed) logit models are developed to investigate the factors that affect mode choice decisions in short- and long-term scenarios. Value of travel time savings (VTTS) is calculated using the marginal rate of substitution derived from the mixed logit models. The results indicate that the option of sharing the AV ride is not as preferable as single occupant AVs across all market segments, which may challenge the benefits that this emerging technology can bring to shared transportation modes. Further, it was found that VTTS is lower for SAVs compared to single occupancy AVs regardless of the time horizon.

Economic and socioeconomic assessment of replacing conventional public transit with demand responsive transit services in low-to-medium density areas

The emergence of demand responsive transport (DRT) services is restructuring mobility in the urban universe. They provide a high level of service and in many cases compete with public transportation modes. However, in less dense areas, where conventional public transit (CPT) services such as buses are inefficient and costly, DRT services could be an alternative that is both profitable and provides passenger satisfaction. This paper investigates the economic and socioeconomic potential of replacing CPT with DRT services. In particular, it focuses on the development and combination of two models. The first is an agent-based model, which describes movements of vehicles and assigns them to passengers according to a utility function. The assignment equilibrium problem is solved for demand that is elastic to generalized cost alone. The second is an economic optimization model, based on a simulated annealing algorithm, which aims to determine supply conditions that maximize the benefit for the operator, the user, the environment, and society. Four economic problems are discussed and formulated accordingly. In addition, supply optimization is carried out in particular with respect to fleet size, trip fare, and vehicle capacity. Finally, these models are applied to a real case in the Paris metropolitan area where a bus service has been replaced by a DRT system. The results show that though this shift is not beneficial from a societal point of view, bus demand is attracted by a DRT service consisting of 30 vehicles and charging a fare of €0.5. The operator would aim to propose a taxi-service, with small-sized vehicles and higher fares, in order to increase their profitability. User utility, on the other hand, would suggest that public authorities should regulate fares and vehicle capacity (more than 6 seats). Fare regulation, in particular, will depend on the fleet size, ranging linearly from €0 for 25 vehicles to €4 for 70 vehicles. Finally, we find through the sensitivity analysis that thresholds exist for demand and fixed costs (respectively 85% and 90% of reference values) beyond which the bus line is more beneficial to society than the DRT service.

Should autonomous shared taxis replace buses? A simulation study

Abstract The introduction of shared autonomous vehicles (SAV) will likely reduce operation cost per vehicle and might thereby allow to enhance conventional public transit systems with numerous small SAVs offering flexible ridesharing-like feeder services. These demand-responsive services could replace conventional bus lines limited by their fixed routes and their fixed schedules. This simulation study explores the potential of replacing conventional bus lines with shared autonomous vehicles in a suburban area of Berlin. Several scenarios with different fleet sizes and vehicle sizes are simulated using the multi agent transport simulation MAT-Sim. The simulation suggests for all evaluated scenarios higher operating costs and only slight travel time savings in comparison to conventional buses. Door-to-door service allows for significant reductions in average walk time, but causes numerous detours which consume a high share of the time gained. A fleet of 150 SAVs with 4 seats each seemed appropriate for the simulated area with approximately 24 000 inhabitants.

Vehicle routing and scheduling of demand-responsive connector with on-demand stations

As an important supplement of conventional fixed-route public transit, flexible transit services draw more attention in low-demand areas recently. Demand-responsive connector is one of those flexible transit services and has already been operated as feeder transit in some cities. This article concentrates on the vehicle routing operation of the demand-responsive connector system with on-demand stations. A two-stage routing model is proposed to minimize the system cost, considering both the service provider and riders, and two solution algorithms are proposed and compared for the routing model. A simulation experiment based on a real-life case study in Nanjing city is conducted to demonstrate the applicability of the proposed vehicle routing model. The results demonstrate that our vehicle routing modeling and optimized algorithm can confidently handle the daily operation of demand-responsive connector services with on-demand stations.

Taxis as a Recourse Option for Ridesharing Services

Ridesharing services commonly offered at airports and to mobility-impaired persons exist worldwide. Unlike operators in conventional public transit, ridesharing operators maintain flexible routes and schedules that are used in providing door-to-door service. These routes and schedules are typically created by using the assumption of perfect foresight about future travel times. In practice, however, vehicles may encounter traffic congestion, be delayed because of road work or an accident, or even break down. Thus, the routes and schedules may adhere to quality-of-service constraints in planning when perfect conditions are assumed, but operationally they often violate such constraints. This paper investigates the effectiveness of routes and schedules created under a deterministic travel time assumption. The paper evaluates practical solutions that force the schedules to include excess slack. Finally, the paper proposes and assesses a recourse option for use in actual operations of assigning to taxis those passengers who are likely to be picked up late. The evaluation was completed on a real-world case study in Richmond, Virginia.

Adapting the Swedish Service Route Model to Suburban Transit in the United States

Since the early implementation of the complementary paratransit provision of the Americans with Disability Act (ADA) in 1990, transit operators in the United States have been challenged by the increasing demand for service and its low productivity relative to traditional accessible bus service. Over the same period, these agencies have been challenged by the cost of a demand for new conventional buses in low-density areas. During the 1980s, Sweden faced a similar challenge as demand for special transportation service (STS), a form of municipal paratransit serving older persons and people with disabilities whose mobility needs could not be accommodated through conventional public transit services, increased after becoming mandatory in 1979. The introduction of the Service Route, a scheduled bus service designed to serve persons who could not be served by conventional transit, resulted in lower costs per passenger, while offering a convenient alternative to STS for many older persons and persons with disabilities. This paper examines the application of the Swedish service route concept in the United States, offering a lower-cost alternative to conventional scheduled bus service for the general public and providing convenient connections to existing traditional bus and rail public transportation services. The specific cost and productivity impacts of two service route systems developed over the past decade in two U.S. suburban counties are presented. These systems provide a lower-cost alternative to the existing advance reservation service while expanding the availability of local bus options for the general public and for transportation disadvantaged populations.

Introduction to special section on paratransit

Over the past few years, private taxi, jitneys, and other paratransit services have blossomed in cities around the world. Scholars have noticed. Two things stand out immediately. First, we don’t know very much about how taxi and paratransit services affect travel behavior and mode choices. Second, we know even less about who uses these systems. Because these services tend to serve niche populations, it is difficult to assess who an “average” rider is. What we do know about taxi services and paratransit is that they are important complements of—and occasional substitutes for—conventional fixed-route transit. This special section of the Journal of Transport and Land Use presents three articles in which the authors examine complementary travel modes to conventional public transit systems. Together these three papers provide evidence of how informal and nontraditional transit operates in conjunction with established transit services as well as competes with certain types of services.

Discussion on the Land Using Mode of Conventional Public Transit Oriented City

For the contradiction between the current urban public transport system and land use status in many small and medium-sized cities, the purpose of the paper is to present the counterplan framework of the land using mode and to provide mechanism and ensuring for the land using mode that matches the conventional public transit system.

Research on the Multiroute Probit‐Based Public Transit Assignment Model Based on Bus Stop

A public transit network differs from a general road network. The passenger flow of bus stops and the limited capacity of buses have a greater effect than road traffic flow on the running time of buses. As a result, conventional public transit assignment models that adopt the econometric road network path concept have numerous limitations. Based on the analysis, the generalized bus trip time chain is analyzed, and the concept of a congestion function is proposed to describe the relationship between trip resistance and flow in the current paper. On the premise of this study, the transit network resistance function is formed and the multiroute probit‐based loading model is established. With using STOCH or Dial′s algorithm, the process of distribution is proposed. Finally, the model is applied to the transit network assignment of Deqing Town in Zhejiang Province. The result indicates that the model can be applied to practical operations with high‐precision results.