Snehamay Khasnabis

Access to Health Care and Nonemergency Medical Transportation: Two Missing Links

Although lack of access to nonemergency medical transportation (NEMT) is a barrier to health care, national transportation and health care surveys have not comprehensively addressed that link. Nationally representative studies have not investigated the magnitude of the access problem or the characteristics of the population that experiences access problems. The current study, relying primarily on national health care studies, seeks to address both of those shortcomings. Results indicate that about 3.6 million Americans do not obtain medical care because of a lack of transportation in a given year. On average, they are disproportionately female, poorer, and older; have less education; and are more likely to be members of a minority group than those who obtain care. Although such adults are spread across urban and rural areas much like the general population, children lacking transportation are more concentrated in urban areas. In addition, these 3.6 million experience multiple conditions at a much higher rate than do their peers. Many conditions that they face, however, can be managed if appropriate care is made available. For some conditions, this care is cost-effective and results in health care cost savings that outweigh added transportation costs. Thus, it is found that great opportunity exists to achieve net societal benefits and to improve the quality of life of this population by increasing its access to NEMT. Furthermore, modifications to national health care and transportation data sets are recommended to allow more direct assessment of this problem.

NETSIM-based approach to evaluation of bus preemption strategies

Preemption techniques are designed to provide preferential treatment to buses at signalized intersections. Uncertainties resulting from variations in passenger boardings and unboardings at bus stops make the prediction of the exact arrival times of buses at intersections extremely difficult. A preemption strategy, if properly designed, can provide continuous green phases to buses at successive intersections. It is unfortunate that a validated technique that can be used to assess the possible consequences of signal preemption is not available. The authors present the application of a simulation model, NETSIM, to make such an assessment. NETSIM was selected because of its ability to microscopically simulate vehicular movements on a street network and its ability to track an individual vehicle from the source to the sink by the use of an animation feature. A major bus route in Ann Arbor, Michigan, was used as the experimental site. The major conclusions are that NETSIM, when properly validated, can generate delay and queue-related measures of effectiveness that are compatible with field data and that the animation feature of NETSIM can be used to assess the operational consequences of bus preemption on a series of intersections on a bus route. For the volume levels studied in the project, savings in delay along the bus route resulting from preemption exceed the increases in delay along the cross street. Further research is needed to determine whether the net savings in delay, when balanced against the costs of installing and maintaining the system and the inconvenience to motorists along the cross street, make the system worthwhile.

PROCEDURE TO EVALUATE ALTERNATIVES TO TRANSIT BUS REPLACEMENT

The addition of new buses to a transit agency’s fleet is a capital-intensive project. In an average year, more than 3,500 buses are purchased by FTA grantees. The annual cost of bus replacement easily exceeds

Signal preemption as a priority treatment tool for transit demand management

1 billion. A procedure to evaluate alternatives to bus replacement is presented. Two generic alternatives are identified—rehabilitation and remanufacturing. The former approach focuses on the repair of engines and machine components. The latter approach is to restore a vehicle’s structural integrity. The evaluation procedure is based on economic principles and quantifies the benefits and costs associated with postponing a bus replacement, either by rehabilitation or remanufacturing. A modified benefit-to-cost ratio (B/C) technique is proposed that incorporates intangible benefits and disbenefits, as well as a risk penalty associated with the extended use of an older bus. As an alternative to computing the B/C, the recommended approach is to estimate the maximum investment that can be justified in a rehabilitation or remanufacturing project using the derived benefits. An affordability index is developed that is sensitive to the risk penalty used. Numerous examples are presented to demonstrate the application of the proposed procedure. Finally, a set of guidelines is presented to assist transit agencies in determining the economic viability of postponing a new-bus purchase by rehabilitating or remanufacturing an older bus.

Asset management framework for state departments of transportation to meet transit fleet requirements

The purpose of this paper is to present an analytic procedure for testing the feasibility of using signal pre-emption as a tool for transit demand management. Signal pre-emption is designed to reduce delays, thus resulting in reduced cycle time, reduced fleet size and reduced operating cost. Further, reduced travel time is likely to make the transit system more attractive, thus generating more rider-ship and higher revenue. A software PREEMPT was developed that can estimate driving times based upon higher speeds and can calculate the fleet size, operating costs, revenue, and revised demand. Using the data base from a recently completed UMTA sponsored study, 3 transit sectors in the Detroit area were analyzed for base condition and various pre-emption scenarios, and the results are presented in this paper.

APPLICATION OF A BUS GARAGE LOCATION AND SIZING OPTIMIZATION

State departments of transportation that provide the bulk of matching funds to local transit agencies for the purchase of new buses are duly concerned about the escalating costs of new buses and the lack of sufficient funds to keep up with their replacement costs. An asset management framework is presented that can be used by state departments of transportation to (a) allocate capital dollars for the dual purpose of purchasing new buses and rebuilding existing buses within the constraints of a fixed budget when the needs of all constituent agencies in a peer group are considered and (b) distribute funds among the agencies equitably. The proposed framework includes two optimization models. Model 1 attempts to maximize the weighted fleet life of all the buses being purchased and rebuilt for a given peer group within the constraints of a fixed budget. Model 2 is designed to maximize the remaining life of the entire peer group, including the existing buses and those being replaced or rebuilt. Case studies presented to demonstrate the application of the models show that the framework is viable and can be used for the designated purpose with fleet data currently available from transit agencies. Further research on testing the framework is recommended to ensure its applicability under different sets of circumstances.

Optimum Bus Headway for Preemption: A Simulation Approach

Abstract A computationally efficient methodology to size and locate bus garage system changes optimally is outlined. The analytical model developed is applied to a Detroit metropolitan area case study. The case study demonstrates the application of the model and provides an example of the results of its use.

Land Use and Transit Integration and Transit Use Incentives

Preemption techniques are designed to provide preferential treatment for buses at signalized intersections. A preemption strategy, if properly designed, can provide continuous green phases for buses at successive intersections, thereby reducing travel times and delays along the bus route. However, the length of delay incurred by all the vehicles in the system may be affected by the different bus headways under preemption operation. Unfortunately, no formal technique is available to assess the cumulative delay consequences of bus headways. The application of a simulation model, NETSIM, to test the effect of different headways is presented. NETSIM was selected because it can microscopically simulate vehicular movements on a street network and because an animation feature within NETSIM is available that allows the user to track an individual vehicle from the source to the sink. A major bus route in Ann Arbor, Michigan, was used as the experiment site. The major conclusions are that NETSIM can generate delay data at various levels of aggregation (e.g., link, node, and route) that can be used to assess the operational consequences of bus headways under preemption conditions. For the volume levels studied in the project, the savings in delay along the bus route resulting from preemption appears to be a good measure for determining the optimum headway.

Incorporating uncertainty and risk in transportation investment decision-making

Planners have often looked on transportation policies as a means of controlling broad patterns of land use. It has been argued that past transportation policies have contributed to decentralization of urban activities resulting in congestion, traffic hazards, and environmental pollution. Others contend that urban land uses reflect location decisions by individual households and employers and that transportation is just one of the many factors that affect such decisions. Thus, public policies in transportation have very little opportunity to alter future land use. The exact effect of transit on the distribution of urban activities, the resulting urban structure, the level of congestion, and air quality is not fully understood. An attempt is made in this paper to document successful cases of transit and land use integration as well as the techniques used by different agencies to bring about such integration. Various studies under the Transit Cooperative Research Program on different aspects of transit and land use policies serve as the basic sources of information for this paper. Eight case studies are examined that encompass a variety of transit modes in urban North America. It is concluded that the accessibility advantages provided by transit may play a crucial role in the concentration of development and in creating economic opportunities. However, transit by itself is not sufficient to guarantee successful transit-focused development. Other major factors are supportive regional and local policies and private investment in concert with the transit program. Further, successful transit and land use integration does not necessarily imply the presence of a high-speed rail system. In a strong market, when support policies are in place, light rail and busways can also be used to channel urban growth.

FRAMEWORK FOR ANALYZING ALTERNATIVES TO TRANSIT BUS REPLACEMENT

This paper presents a framework for addressing uncertainty and risk for large-scale transportation investments involving public–private participation. Demand, fare/toll and demand responsive costs are considered in the uncertainty analysis. Uncertainty analysis provides information on economic feasibility of the project. A set of relaxation policies is proposed to form various Ownership, Tenure and Governance (OTG) strategies reflecting the nature and level of participation by the public and private entity. A Monte Carlo Simulation-based Value at Risk is used to quantify risk. Finally, a methodology is proposed to integrate uncertainty and risk. The framework is tested on the proposed multibillion dollar Detroit River International Crossing connecting the cities of Detroit in the USA with Windsor in Canada. The analysis provides insights to probable outcomes for this transportation infrastructure investment under different OTG scenarios.