Jesus M. de la Garza

Improving GPS-based vehicle positioning for Intelligent Transportation Systems

Intelligent Transportation Systems (ITS) have emerged to utilize different technologies to enhance the performance and quality of transportation networks. Many applications of ITS need to have a highly accurate location information from the vehicles in a network. The Global Positioning System (GPS) is the most common and accessible technique for vehicle localization. However, conventional localization techniques which mostly rely on GPS technology are not able to provide reliable positioning accuracy in all situations. This paper presents an integrated localization algorithm that exploits all possible data from different resources including GPS, radio-frequency identification, vehicle-to-vehicle and vehicle-to-infrastructure communications, and dead reckoning. A localization algorithm is also introduced which only utilizes those resources that are most useful when several resources are available. A close-to-real-world scenario has been developed to evaluate the performance of the proposed algorithms under different situations. Simulation results show that using the proposed algorithms the vehicles can improve localization accuracy significantly in situations when GPS is weak.

Sampling Procedure for Performance-Based Road Maintenance Evaluations:

Maintaining the road infrastructure at a high level of condition with generally limited amounts of available funding is a challenge for many transportation agencies. To address this challenge, many road administrators worldwide have implemented performance-based maintenance contracts. In performance-based maintenance contracts, road administrators define performance measures (e.g., performance-based specifications) that specify the minimum condition at which the asset items are to be maintained. To ensure that contractors maintain the asset items according to these measures, road administrators must design and implement a comprehensive and reliable performance monitoring process. One of the most important areas within the performance monitoring process is inspection conducted in the field. Defining a procedure that guarantees the success of field inspections is a challenge. When defining such a procedure, road administrators must consider budget and time limitations, among others. Since performance-based road maintenance contracts are relatively new, the availability of guidelines for such issues (with focus on performance-based contracts) is limited. That need is addressed by presentation of a three-stage and seven-step statistical sampling procedure developed to ensure that findings from field inspections will be reliable and representative with high confidence of the actual condition of asset items in the entire population. Also presented are three alternative approaches for sampling for the cases in which sampling needs to be performed not just once but multiple times over the duration of a performance-based road maintenance contract.

Using simulation to understand the impact of deferred maintenance

Understanding the impact of deferred maintenance on a highway system can help policy makers and transportation planners in the decision process on how to best utilize limited resources to provide for an areas total infrastructure needs. This paper presents the development of a framework and methodology to use dynamic simulation to understand and quantify the impact of deferred maintenance and the effect on user and non-user benefits. This simulation will allow the testing of policies or assumptions for their impact over time, in order to gain insight into the problem solution. A hypothetical region is used to demonstrate the use of the framework, and three possible measures of effectiveness, total net benefits per capita, revenues less expenditures, and benefit-cost ratio, are introduced that could be utilized to help decision-makers understand the impact of various maintenance funding rates on different interest groups being served within the community. The model can be calibrated to a region to provide specific impact information for that location.

Issues Related to the Assessment of Performance-Based Road Maintenance Contracts

In the late 1980’s and early 1990’s few transportation agencies around the world considered privatization as an alternative to improve the efficiency of the services provided to the public. As a result of this initiative, new partnerships between the public and private sector for maintaining and preserving public roadways were developed and implemented. These new contracting relationships are better known as Performance-Based Road Maintenance Contracts (PBRMC). PBRMC calls for performance-based work, in which a desired outcome is specified rather than a material or method. This contracting scheme promises to be an excellent tool to improve government efficiency in maintaining transportation networks; however, without proper analysis, this type of contract could likely yield adverse outcomes. Since PBRMC are relatively new, the availability of reliable and comprehensive sets of guidelines to evaluate the effectiveness and efficiency of this type of contract is limited. Transportation agencies currently rely on criteria and procedures they have had developed from their traditional methods used to evaluate performance. Unfortunately, some of these procedures cannot appropriately assess the benefits, if any, accrued by the government as a result of engaging a private contractor to perform outcome-based road maintenance activities. This paper presents a general overview of a framework for monitoring PBRMC more comprehensively and accurately. The framework considers the assessment of five main areas -- level of service effectiveness, cost-efficiency, timeliness of response, safety procedures, and quality of services -- in order to guarantee the comprehensiveness and reliability of the evaluation process. The major contribution of this framework is to provide transportation agencies with guidelines for evaluating the effectiveness and efficiency of PBRMC as an alternative delivery method to maintain and preserve the roadway system.

GPS-free cooperative mobile tracking with the application in vehicular networks

In this paper, the problem of mobile tracking in dense environments is studied. The Global Positioning System (GPS) is the most accessible positioning technique. However, GPS does not work properly in indoor and dense areas, as the receiver typically does not have access to a sufficient number of line-of-sight satellites. Therefore, localization in these networks can be alternatively done by using measurements collected within the network and without the aid of any external resources (e.g., GPS). The mobile tracking problem includes several static reference nodes whose locations are fixed and known, and many mobile nodes whose locations are unknown and needed to be determined. The problem of mobile tracking can be solved in two forms: centralized and distributed. A centralized algorithm can result in high complexity and latency, while a distributed algorithm might lead to large estimation errors. In this paper, a novel cooperative localization technique is introduced which is able to deliver a promising localization accuracy while maintain the latency and complexity as low as possible. The performance of the proposed algorithm is compared with those of other algorithms in terms of localization accuracy, latency, and required data communication through computer simulations. The simulation results show the effectiveness of the proposed algorithm in comparison with either centralized and distributed algorithms. An important application of this work is vehicle localization in dense environments where the vehicles do not have access to GPS satellites and must be localized by the elements within the network.

Implementation of Level-of-Service Component for Performance-Based Road Maintenance Contracts

In the performance-based road maintenance setting, the contractor is given the responsibility and flexibility to maintain the roadway systems assets using innovative approaches. Increased control of the contractor and innovative techniques implemented by the contractor should yield a product with a predefined quality. This can be ensured by implementing a systematic performance measurement system composed of performance criteria, performance targets, and protocols for taking the measurements necessary to determine whether the contractor meets such criteria and targets. This performance measurement system should produce appropriate and user-friendly reports that can effectively communicate the results to stakeholders, such as the transportation agency, the contractor, and the traveling public. The Virginia Department of Transportation (VDOT) has been using a systematic and comprehensive framework to measure the performance of its performance-based road maintenance contractors and to communicate the results effectively to stakeholders. The steps for implementation of the level-of-service effectiveness component of such a framework are presented to illustrate to transportation agencies how the framework works. Although the framework was developed and implemented for VDOT, it can be adopted by any other transportation agency and adapted to meet that agencys own needs.

Computer Simulations of the Vehicle Localization for Intelligent Transportation Systems

In this paper, an integrated framework and a smart algorithm for vehicle positioning are proposed. The standalone Global Positioning System (GPS) cannot provide accurate location information in dense and indoor environments. Therefore, an integrated framework is proposed which exploits additional positioning technologies - including vehicle-to-infrastructure and vehicle-to-vehicle communications, radio-frequency identification, map-matching, and dead reckoning - for vehicle localization. Since different applications require different location accuracy, a smart algorithm is also provided which shows how different localization technologies under various situations are selected and used to obtain the desired accuracy with the least amount of complexity. A series of comprehensive MATLAB simulations are conducted to evaluate the performance of the algorithms. Simulation results show that: (1) standalone GPS is not a reliable positioning technique in all situations; (2) an integrated technique using several positioning technologies is required to achieve the minimum application requirements in all situations; and (3) using the smart algorithm, the required accuracy and latency can be achieved by selectively adding or removing localization resources.

Efficiency measurement of the maintenance of paved lanes using data envelopment analysis

While the road maintenance performance measurement systems that are currently in use investigate maintenance level of service (i.e. effectiveness of the road maintenance), the fundamental relationship between the maintenance level of service and the budget requirements (i.e. the efficiency of road maintenance) has not received as much attention. Given that not knowing how ‘efficient’ transportation agencies are in being ‘effective’ can lead to excessive and unrealistic maintenance budget expectations, there is a need for a performance measurement system that can assess the overall efficiency of road maintenance operations. To address this need, a framework was developed and implemented to assess the relative cost efficiency of eight counties in Virginia, USA in maintaining the paved lanes of the Interstate roads. Such framework is developed using a methodology known as data envelopment analysis which is based on the production theory and principles of linear programming. The results indicate that the Rockbridge County is the most efficient and the Roanoke County is the least efficient in maintaining the paved lanes. The findings of this research are intended to be used as guides for benchmarking as well as managerial actions and policy making for decision making with respect to road maintenance.

Long-Term Significance of a CII Best Practices Course

AbstractThe Construction Industry Institute (CII) was established to improve the cost-effectiveness, safety, timeliness, and quality of the construction industry. Through research, more than a quarter of a century after it was chartered, CII has been able to establish 15 best practices and to document their effect in making significant strides to improve the delivery of capital projects in the United States and around the globe. In 2007, CII began an effort to formally expose graduate students to these best practices by developing a graduate-level course taught by industry professionals from CII member companies. After its sixth offering in 2012, more than 800 students distributed across the United States and Canada in multiple universities have learned about CII and about the role that CII’s best practices have played in improving the construction industry. The course has proven itself to be a win-win-win-win for students-faculty-industry-CII. This paper describes the course evolution as well as its sign...