Fabian Cevallos

Using AVL Data to Improve Transit On-Time Performance

This paper describes an approach for improving on-time performance at transit agencies. It takes advantage of the schedule adherence information from an AVL system. A methodology that can be used to update the bus timetables by using AVL schedule adherence data is described. Using statistical analysis, the main goal is to maximize the density area of the on-time performance range. From this distribution, the optimal value is obtained and used to update the times in the timetables. Then, a comparison process is used to assess the on-time performance improvements. In addition, a simulation process is presented to provide a different perspective than the statistical methodology. This approach also presents possibilities for further on-time performance improvements. To demonstrate the applicability of this research, a case study using data from Miami-Dade Transit is included. The on-time performance calculations for Routes 99 and 57 also are presented.

Selecting Bus Stops for Accessibility Improvements for Riders with Physical Disabilities

Bus stops are key links in the journeys of riders with disabilities. Inaccessible bus stops prevent people with physical disabilities from using fixed-route bus services, thus limiting their mobility. Due to limited budgets, transit agencies must select bus stops for which their improvements, as part of the effort to comply with the Americas with Disabilities Act (ADA), can maximize the overall benefits to riders with physical disabilities. In this paper, an analytic hierarchy process (AHP) was applied to combine the factors affecting the benefits to riders with physical disabilities, and a binary linear programming model was used to identify bus stops for ADA improvements based on budgetary and construction cost constraints. As an application example, the optimization model was applied to the 5,034 bus stops in Broward County, Florida. Compared to the usual approaches, the optimization model provides a more objective platform on which to identify bus stops for ADA improvements.

Multiobjective Optimization Model for Prioritizing Transit Stops for ADA Improvements

Inaccessible transit stops prevent people with disabilities from using fixed-route transit services, thereby limiting their mobility. The Americans with Disabilities Act (ADA) prescribes the minimum accessibility requirements for transit stops for riders with disabilities. In addition, transit agencies may also choose to implement the “universal-design” paradigm, which involves higher design standards than current ADA requirements and includes amenities that are useful for all riders, such as shelters and lighting. Because of budget limitations, however, transit agencies can select only a limited number of transit stops for ADA improvements each year. To increase the impact of these improvements, it is desirable that transit stops be selected such that they will maximize the overall benefits to patrons with disabilities. This paper describes a multiobjective binary nonlinear programming model for selecting, within a limited annual budget, a priority set of transit stops for improvements. The model aims to...

A Genetic Algorithm for Bus Schedule Synchronization

The bus transfers synchronization problem is to find an optimal bus schedule for the entire transit system that minimizes riders’ transfer time. This is a complicated problem of the large set of binary and discrete values involved. The combinatorial nature of the problem poses a computational burden and makes it difficult to solve using classical methods. This paper presents a Genetic Algorithm (GA) approach to synchronizing bus schedules to minimize transfer times. The algorithm takes existing scheduled timetables and ridership data at transfer locations as input and addresses the randomness of bus arrivals. The algorithm takes existing scheduled timetables and ridership data at transfer locations as input and addresses randomness in bus arrivals. The algorithm attempts to find an optimum solution for the bus schedule synchronization problem by shifting existing timetables. Using scheduling data from Broward County Transit, total passenger transfer times were calculated for the existing and the proposed systems. This algorithm was able to reduce system-wide transfer time by 13.4%. Results from this case study and recommendations for future research are presented.

Use of Movable Bus Stop Loading Pads: Feasibility and Design Alternatives

The Americans with Disabilities Act (ADA) of 1990 requires bus stops to be accessible for individuals with disabilities. At a minimum, bus stops must have firm, stable, slip-resis tant loading pads with connected sidewalks and curb ramps. Consequently, the typical approach of transit agencies has been to install permanent concrete loading pads at bus stops. This study explored alternatives to conventional concrete pads with movable pads that could be installed quickly, resulting in savings in construction and labor costs and minimizing both disruptions to traffic and impacts to abutting businesses. Potential design alternatives in terms of materials and structural support for these pads were evaluated. The review focused on existing and alternative design materials, especially in applications other than for transit purposes. Six materials were evaluated based on their structural performance, long-term durability, adaptability, life cycle cost, aesthetics, and safety and accessibility of transit riders with mobility devices. Of the six materials, plastic lumber and metal were found to have the highest potential to replace conventional designs. Two design alternatives that rely on the concept of bridge construction were introduced, both of which consist of four major components: foundation, slab, beam, and connections. These new design alternatives are anticipated to minimize maintenance of traffic and the need for heavy machinery to excavate, fill, and/or compact the soil.

Characteristics of Bus Transit Vehicles in the United States: A 30-Year National Trend Analysis

In 2015, transit agencies in the United States spent over 60% of their bus transit capital funds on their revenue vehicles. Using 30 years of data from the National Transit Database (NTD), this paper examines the national trends of seven major characteristics associated specifically with bus revenue vehicles. These trends can provide important information on where the market might be heading and aid in planning decisions on transit investments. The characteristics examined include the number of vehicles, spare ratio, average age, average capacity, Americans with Disabilities Act (ADA) accessibility, vehicle reliability, and vehicle operations and maintenance expenses. Some findings from the trend data include: (1) a steady increase in the privatization of bus services; (2) the average spare ratios have consistently exceeded the maximum of 20%, as suggested by the Federal Transit Administration (FTA) for systems operating with more than 50 vehicles; (3) vehicles operated by contractors tended to be significantly newer than those operated directly by transit agencies, although the gap has narrowed in recent years; (4) vehicles operated directly by transit agencies tended to have higher seating and standing capacities than those operated by contractors; (5) there was a tendency among transit agencies to trade seats for more standing room; (6) by 2015, nearly all bus vehicles were ADA-compliant, and increasingly vehicles with lifts were converted to vehicles with ramps/low-floor; (7) reliability of vehicles considering the number of mechanical failures per million revenue vehicle miles has significantly improved over the years; and (8) contractors spent significantly less on average than transit agencies in operating and maintaining their vehicles.