Kofi Obeng

North Carolina Agricultural and Technical State University | NC A&T · Department of Marketing, Transportation and Supply Chain

Dynamic factor adjustment models are applied to analyse input inflexibilities in public transit systems. Based on a panel data of 44 U.S. single mode bus transit systems, labour input is found to be the most flexible with an adjustment speed of 17.8% annually while non-labour and capital inputs do not adjust. However, it is found that transit syste...

This paper studies incentive-based subsidy to transit systems to improve performance. It derives a formula for optimal effort that equalizes marginal cost and marginal benefit and derives some principles from it among which is that the larger the value of a transit system’s performance criterion the larger the effort it will exert to improve it. Ne...

This paper addresses heterogeneity in the deterministic portion of a cost frontier and in the parameterisation of technical inefficiency using an unbalanced panel of bus transit systems. It conceptualises six groups of variables which affect heterogeneity in cost and technical inefficiency: organisational size, ownership, service delivery methods,...

This paper studies the effects of regulations, input subsidies, their interactions and technical efficiency on cost efficiency and shows how a firm's cost efficiency relates to society's cost efficiency. It finds that from societal viewpoint, the average US public transit system is 45% cost efficient, a product of 84.4% technical efficiency and 53....

This paper studies the effects of non-contracting regulations on the efficiency of U.S. public transit systems. First, it estimates a system of cost and input demand equations and second, a frontier equation with technical inefficiency a function of regulation and heterogeneity variables. It finds that bus useful-life regulation makes transit syste...

The study analyzes the perception of airport safety by travelers, and how it is related to satisfaction with passenger screening experiences and the perception of public transit safety. It uses the Omnibus Household Survey data collected by the U.S. Bureau of Transportation Statistics and estimates a structural equations model. It finds a positive...

This article studies the relationships between perceptions of threats to valued job features, total job (job insecurity), and career commitment among university professors, using the context of post-tenure review policy. It surveys professors from a randomly selected sample of 74 universities that have implemented post-tenure review policies and pr...

Using an Indirect Production Frontier (IPF), this article examines technical inefficiency within a latent class framework while simultaneously accounting for allocative distortions from operating and capital subsidies. It identifies two latent classes of US public transit systems, one characterized by economies of scale with 16.61% technical ineffi...

This paper analyzes pedestrian injury severity from automobile crashes at signalized intersections in a medium-size city. It estimates an ordered logit model of injury severity and finds that vehicle type, gender, land-use, speed limit, traffic volume, the presence of sidewalks and visual-obstruction significantly explain pedestrian injury severity...

This paper determines the deadweight loss of operating and capital subsidies by extending Tullock's (1998) work. It finds that when both subsidies are received deadweight loss is 6.83% of total cost or $0.861 million on the average, $0.780 million when operating subsidy is received and $0.0503 million when capital subsidy is received. Decomposing t...

This paper estimates a single class stochastic cost frontier model that accounts for heterogeneity by including background variables and a latent class model of the same specification. It is found that both the two-sided random errors and one-sided errors (cost inefficiency) are substantially smaller in the latter model than it is in the former, su...

This paper conceptualizes various discount strategies used by airlines. Using a constrained revenue maximization model that assumes interdependent demand, it develops rules to guide decision-making, and shows that the large fare discount-many discount seats and small fare discount-few discount seats strategies are optimal. Empirical support is prov...

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This paper analyzes gender differences in crash risk severities using data for signalized intersections. It estimates gender models for injury severity risks and finds that driver condition, type of crash, type of vehicle driven and vehicle safety features have different effects on females' and males' injury severity risks. Also, it finds some vari...

This paper uses an indirect production function to decompose the effects of subsidies on output into the lump-sum, cost and inefficiency effects. Using 2006 data for U.S. transit systems it estimates an indirect production function and uses the results to calculate these effects. It finds that the lump-sum effects exceed the other effects and that...

This study determines the effectiveness of strategic planning as an effective tool of strategic management in public transit agencies. It finds that an effective strategic planning requires top managers’ active roles in defining the strategic direction of the organization and creating an environment that recognizes strategic planning as a tool of s...

This paper determines the deadweight loss of operating and capital subsidies offered US public transit systems by extending previous research by Tullock (1997). It develops a method for calculating deadweight loss and using 2006 data for 227 single mode bus transit systems it estimates cost and share equations to obtain the coefficients needed to c...

The objective of this article is to determine the relationships between board members' involvement in prescribed activities of boards of directors and the performance of public transit systems. It analyzes the degree to which board members are involved in prescribed activities of boards of directors as an indication of their effectiveness using sel...

Transit service is a for-hire, shared urban passenger transportation service that is fixed-route and scheduled. The study of the economics of transit systems (especially U.S. public transit systems and U.K. public transport) has been responsible for many developments in transport economics, including advances in demand forecasting, cost modeling, p...

This paper extends previous works on total factor productivity decomposition when firms receive both operating and capital subsidies. It shows that previous works considered either the lump-sum or substitution effects of these subsidies but not together. Using constrained cost minimization as the framework it offers formal proofs to show that cost...

This paper examines variation in airline fares for trips in a medium-size travel market. It develops a conceptual model of fares offered, and uses daily information about fare, plane and flight characteristics, and trip characteristics easily available on the internet. Based on this information it estimates a two-way fixed effects model of airline...

This note examines if offsetting driver behavior affects rear end crashes at intersections with red light cameras. It models offsetting driver behavior and estimates simultaneous probit equations to analyze this behavior. It finds that in the city considered the effect of red light cameras on the probability of a rear end crash occurring is very st...

This paper identifies the characteristics of strategic planning systems of transit agencies that enhance these agencies' abilities to respond effectively to federal legislative requirements and mandates, and have positive community impacts. These characteristics are, each unit or division must develop its own action plan to be combined into a syste...

This article examines injury severity in crashes that occur within signalized intersections and identifies some factors that explain them. It uses a random effect ordered logit model and an unbalanced longitudinal panel data for 303 intersections for one medium-size city. Among its findings are 3% and 0.29% lower probabilities of sustaining evident...

This paper identifies some determinants of possible injuries from crashes that occur at signalized intersections using a conditional probability model. It uses longitudinal data for one city and calculates the marginal effects of these determinants. Among its findings, an airbag deploying in a crash reduces the conditional probability of sustaining...

In this article, we estimate a Tobit model of property damage costs of crashes that occur at signalized intersections with data from one US city - Greensboro, North Carolina. The model includes data on technological variables, types of crash, types of vehicle, traffic and intersection characteristics, and driver condition at the time of crash. The...

This study examines public transit boards of directors' role performance, prescribed activities that facilitate role performance, relationships between the roles and prescribed activities, and characteristics of boards and their members that affect members' involvement in board activities. It surveys public transit boards and analyzes the resulting...

This study extends the previous work of Burkey and Obeng (2004) that examined the impact of red light cameras on the type and severity of crashes at signalized intersections in Greensboro, NC. The extension takes the following form. First, we extend the data to cover 57 months, and to include demographics, technology variables, the condition of a d...

Urban transit systems are faced with declining ridership and increasing deficits in recent years. Improving the productivity of transit systems in such unfavourable operating conditions is unquestionable. The sources of productivity change in bus transit systems in the USA between 1985 and 1997 are investigated by using the non‐parametric Malmquist...

This is an update to the October, 2003 version of this report. Using the latest available data, we include an additional 12 months of accident data. Additionally, several data coding errors were discovered in the original data set, and corrected for this report. Therefore, results from the October, 2003 report should be disregarded. This paper anal...

This paper examines organizational commitment (affective, normative, and continuance commitment) of employees in five public transit systems and identifies its determinants. It develops a survey instrument to collect information on organizational commitment and relates commitment to job, organizational, and employees' characteristics. The paper fin...

This paper addresses the performance of public transit systems. It uses the methodology of Obeng and Sakano (2000, 2002) to decompose total factor productivity (TFP) among its sources. The results show decline in TFP without an accounting for operating and capital subsidies and TFP growth when these subsidies are considered. The contributions of th...

This paper decomposes the rate of growth of total factor productivity (TFP) in public transit systems among input demand effects, an indirect output effect, an indirect technical change, pure scale effects and pure technical change. An application of the decomposition to selected transit systems is provided. The application shows that the effects o...

This article uses survey data to determine motivations and impediments to collaboration (i.e., contracting, merger/consolidation, and strategic alliance) among public transit systems in the United States. The results suggest that transit systems are more likely to contract out passenger service if they are involved in the initiation of the collabor...

This paper extends previous works that view transit systems as minimizing their after-subsidy costs. The paper uses the expense preference behavior model in economics and derives first-order conditions for the manager. From the first-order conditions, the paper formally shows that the decomposition of relative price inefficiency between management...

Past studies relied on ad hoc associations to establish relationships between productivity on one hand and operating and capital subsidies on the other. This article deviates from these studies. It builds on recent research based on private cost to derive a total factor productivity formula that includes subsidy effects. It specifies an empirical m...

Past studies relied on ad hoc associations to establish relationships between productivity on one hand and operating and capital subsidies on the other. This article deviates from these studies. It builds on recent research based on private cost to derive a total factor productivity formula that includes subsidy effects. It specifies an empirical m...

Top management leadership and employee empowerment are considered two of the most important principles of total quality management (TQM) because of their assumed relationship with customer satisfaction. As a result, many top management leadership and employee empowerment strategies and practices have been suggested in the management literature. How...

U.S. urban transit systems receive operating and capital subsidies from various levels of government. Each firm minimizes its cost net of subsidies subject to its production function. The first order conditions from this minimization give a set of equations that are estimated using a stochastic frontier approach. From the results are calculated tec...

Among the findings of this study are that subsidies induce overuse of labour and fuel relative to capital in most transport firms. Also, it finds that the size of allocative distortion depends not only on firm size, but also on whether the firm is private, public, or purchases transport. Furthermore, the paper finds that subsidies reduce labour wag...

This study examines two applications of total quality management (TQM) in public transit firms. It develops a model of organizational transformation process and assesses the TQM applications based upon this model. Further, it develops principles that transit firms can follow in implementing TQM.

There are many studies, including those of J. Pucher et al. and S. C. Anderson, that found higher costs to be associated with transit operating subsidies. However, none of them investigated the effect of state and local federal subsidy formulas on cost efficiency of transit operations. In this article, the subsidy-cost relationship is derived by us...

This paper examines allocative distortions from subsidies in single mode bus transit systems. A system of equations consisting of a production function, operating and capital subsidy equations, and two relative input cost equations are estimated using single mode bus transit data. From these equations it is found that all together the subsidies cau...

The common econometric approach to the study of subsidy impacts on costs does not consider the changes in the ratios of the marginal products of the inputs brought about by the subsidies and which affect the cost function. Instead, this approach includes subsidies as an explanatory variable in the cost function. This paper presents an alternative a...

This paper studies subsidy-induced technical inefficiencies in public transit systems using data envelopment analysis. The DEA method is employed to estimate a production frontier using the physical quantities of labor, fuel, and fleet size as inputs and vehicle miles as output. Next, the influence of subsidies on efficiency is examined by re-estim...

This paper examines bus ride times of exceptional school children in North Carolina. It uses levels of service data, which show excessive ride times for exceptional school children, to form clusters of local education agencies. From these clusters short term objectives or standards for maximum ride times are determined for each cluster. Among the f...

Performance in single mode bus transit systems is analyzed in this paper. The paper points to two potential problems in using partial productivity and other measures in assessing the performance levels of transit systems. One solution suggested is total factor productivity which is shown to be mathematically related to many of the traditional measu...

This technical note comments on a 1990 paper by Sumanth and Adya that appeared in this journal. In that paper the authors determined total productivity and showed how innovations occurring in transit systems they analyzed have affected it. Using the definition of the authors, it is shown that there is a misspecification problem in the equations use...

The broad aim is to review the technical literature on productivity and performance indicators, and to establish a set of guidelines for improved approaches to the definition, measurement and implementation of indicators. The economic literature on productivity levels and growth rates will be reviewed and contrasted to the more established transpor...

This paper investigates total factor productivity as a unified measure of transit performance. The approach uses the shift in the cost function of inputs and outputs as the measure of change in productivity. A three step regression procedure was used to estimate model parameters. The approach was applied to a sample of transit agencies. Predictor v...

Analyzes the sources of recent changes in bus transit output using an econometric growth model. The model is derived from the economic theory of production and cost functions. Using pooled data from 1979 to 1985 for 74 transit systems selected based on consistency in reporting, the growth model is estimated and used to decompose the changes in outp...

This paper develops a conceptual framework for bus maintenance based on path analysis and applies it to forty-eight bus transit systems. The application determines the total, direct, and indirect effects of the variables identified as having significant causal links with maintenance cost per mile. These variables are identified using the stepwise r...

This paper develops a conceptual model to classify bus transit policy variables based on their effects on the performance levels of the various inputs and total performance measured by the presence or absence of (dis)economies of scale. The four groups of variables identified in the study include those withi. Strictly positive outcome—these include...

This paper develops a neoclassical cost function for demand responsive transit (DRT) system and uses it to test the economies of scale hypothesis. The results show economies of scale and further show that the economies can be explained by speed, local and state subsidies, utilization of seating capacity, fleet utilization and an increase in the num...

Improvement of transit performance depends first on the ability to measure performance levels. The paper introduces the concept of total-factor productivity as a unified measure of transit performance. The approach uses the shift in the cost function of inputs and outputs as the measure of change in productivity. A three-stage least-squares estimat...

Develops a neoclassical cost function from cross-sectional data pertaining to 62 bus transit systems. The cost function is used to study the effects of total factor productivity and input substitution on cost. Labour and fuel productivity and input improvements are important actions to reduce average cost. Long- run scale diseconomies are found in...

Shows that: 1) for unconstrained net welfare maximization, the ratio of fare to its corresponding elasticity of demand is constant; 2) consistent deviation of marginal revenue from marginal cost is required for constrained net welfare maximization. The application of the methods to a transit system shows that the Baumol-Bradford rule will generally...

This paper tests the hypothesis that transit input demand is inelastic. A homogeneous translog cost model is developed from which the elasticities of input demand are calculated. It is found that the hypothesis is true for labor demand, partly true for diesel fuel demand and not true for electricity demand in the relevant range. That is, the hypoth...

Studies on optimal fare subsidy have generally been based on welfare analyses. Treats deficits explicitly in the objective function and shows that the resulting subsidy is sufficient to yield Pareto optimal outcome. Subsidies should be inversely proportional to transit average cost elasticity. Providing subsidies which depend jointly on fare elasti...