Flex-route Transit Research Articles

The benefits of introducing meeting points into flex-route transit services

In this paper, to improve the reliability of flex-route transit service under uncertain travel demand, a meeting point strategy is proposed in which passengers can be picked up and dropped off either at their reserved stops or at meeting points that are within their acceptable walking distance. A two-stage optimization problem is introduced into the design of flex-route transit operations. Mixed integer programming (MIP) is employed to formulate the problem with a twofold objective: to serve as many requests as possible and to minimize the total trip time of the accepted passengers. A memetic algorithm is adopted to solve the problem in a reasonable amount of time. Simulation experiments based on a real-life flex-route transit service are conducted to assess the benefits of introducing meeting points. The results demonstrate that meeting points can significantly reduce the rejection rate by up to 24% at the cost of walking an acceptable distance. We also find that reducing the passenger fare to compensate for the inconvenience of walking to meeting points constitutes a win–win strategy that benefits both passengers and transit operators.

Fare Strategy for Flex-Route Transit Services: Case Study in Los Angeles

Flex-route transit service is now the most popular type of flexible transits to serve low-demand areas. In this paper, we develop a strategy to help transit planners to determine fare policies when the current traditional fixed-route transits turn to a flex-route operating policy. Analytical modeling and simulations are developed to appraise the service quality provided to different groups of passengers under these two operating policies. To be closer to reality, two criterions, defined as Criterion (NRP) and Criterion (RP), are introduced for further analysis based on the processing of the passengers refused by deviation service. Criterion (NRP) represents the scenario that the refused passengers would switch to other means of transportation and not be considered in the calculation of service quality function, and Criterion (RP) means that the refused passengers would walk to nearest checkpoints for expected service vehicle and be considered in the assessment of cost indicators. In various scenarios, where demand responsive requests pay additional money for personal deviation services and regular riders could expect a discounted fare for the imposed delay, optimal fare policies are derived based on the change of service quality after applying flex-route operating policy. Also, it is found that only fares of regular riders are susceptible to the choice between Criterion (NRP) and Criterion (RP).

A slack arrival strategy to promote flex-route transit services

Flex-route transit, which combines the advantages of fixed-route transit and demand-responsive transit, is one of the most promising options in low-demand areas. This paper proposes a slack arrival strategy to reduce the number of rejected passengers and idle time at checkpoints resulting from uncertain travel demand. This strategy relaxes the departure time constraints of the checkpoints that do not function as transfer stations. A system cost function that includes the vehicle operation cost and customer cost is defined to measure system performance. Theoretical and simulation models are constructed to test the benefits of implementing the slack arrival strategy in flex-route transit under expected and unexpected demand levels. Experiments over a real-life flex-route transit service show that the proposed slack arrival strategy could improve the system performance by up to 40% with no additional operating cost. The results demonstrate that the proposed strategy can help transit operators provide more cost-efficient flex-route transit services in suburban and rural areas.

A dynamic station strategy to improve the performance of flex-route transit services

As an innovative combination of conventional fixed-route transit and demand responsive service, flex-route transit is currently the most popular type of flexible transit services. This paper proposes a dynamic station strategy to improve the performance of flex-route transit in operating environments with uncertain travel demand. In this strategy, accepted curb-to-curb stops are labeled as temporary stations, which can be utilized by rejected requests for their pick-up and drop-off. The user cost function is defined as the performance measure of transit systems. Analytical models and simulations are constructed to test the feasibility of implementing the dynamic station strategy in flex-route transit services. The study over a real-life flex-route service indicates that the proposed dynamic station strategy could reduce the user cost by up to 30% without any additional operating cost, when an unexpectedly high travel demand surpasses the designed service capacity of deviation services.

Feasibility of Flex-Route as a Feeder Transit Service to Rail Stations in the Suburbs: Case Study in Toronto

Flex-route transit service is a promising option to serve low-density urban areas. In this paper, we investigate the feasibility and benefits of replacing feeder fixed-route transit routes in a suburban area by flex-route service. Three routes in the City of Oakville (a suburb of Toronto) that connect with the regional commuter rail (GO Transit) were chosen for the analysis. A simulation of the routes under the existing structure and under several flex-route designs was performed. The results show that assigning an appropriate slack time is essential in having an effective flex-route service and that more slack time does not necessarily translate into more ridership. The results also show that improving the performance of the transit service, in terms of passenger per vehicle revenue hours, will occur only if the ratio of the increase in ridership relative to the added slack time is more than the ratio of the existing ridership relative to the scheduled running time of the original fixed-route service.

Planning and Design of Flex-Route Transit Services

A theoretical investigation is presented of various issues involved in the planning and design of flex-route transit services. An analytical model is proposed for an idealized operating environment with the objective of determining the optimal slack time that should be allocated to a flexroute segment. The optimization objective is defined to minimize total operator and user cost, which enables a systematic examination of complex interactions among the system parameters. An equation is derived for the relationship between the number of feasible deviations and various system parameters such as slack time, zone size, and dwell time. Subsequent analysis shows that the analytical model is elaborate enough to provide substantial insights into various issues that may arise in designing a flex-route service. A simulation analysis is conducted to validate some of the conclusions drawn from the analytical model and to further analyze the implications of stochastic variation in passenger demand.

Planning, Implementation, and Evaluation of OmniRide Demand-Driven Transit Operations: Feeder and Flex-Route Services

Information about the Potomac and Rappahannock Transportation Commission operational test is presented. The test focuses on service planning for the local flex-route transit services and the flag-stop commuter-rail feeder services, as well as their start-ups. Although the intelligent transportation system (ITS) operational test involves the application of automated vehicle location and real-time order-taking, scheduling, and dispatching of software, the planning and start-up operations of the non-ITS-enhanced phase of the flex-route and feeder services are addressed.

Planning, Implementation, and Evaluation of OmniRide Demand-Driven Transit Operations: Feeder and Flex-Route Services

Information about the Potomac and Rappahannock Transportation Commission operational test is presented. The test focuses on service planning for the local flex-route transit services and the flag-stop commuter-rail feeder services, as well as their start-ups. Although the intelligent transportation system (ITS) operational test involves the application of automated vehicle location and real-time order-taking, scheduling, and dispatching of software, the planning and start-up operations of the non-ITS-enhanced phase of the flex-route and feeder services are addressed.