Showing papers by "Mashrur Chowdhury published in 2014"

Infrastructure Cost Issues Related to Inductively Coupled Power Transfer for Electric Vehicles

Abstract: The electrification of vehicles has been accelerated over the last few years due to tighter emission regulations, volatile fuel prices, and progress in standardization as well as improvement of battery technologies. Key hurdles of electric vehicles (EV) to gain a larger share in the automotive market are the cost of the energy storage system (ESS) and the density of the EV charging infrastructure. The achievable range of an EV or full electric driving of a plugin hybrid electric vehicle (PHEV) is limited by its battery capacity. The time to recharge the battery is related to the power level of charging as well as allowable charging parameters to protect the battery life. In order to overcome the constraints of limited range of EVs (all electric driving) as well as the cost of ESS, inductively coupled power transfer (ICPT) is an interesting technology path to be considered, in particular if applied as opportunity (stop-and-go) or in-motion charging (also called dynamic wireless charging or move and charge). In-motion wireless charging could lead to significant reductions of the vehicle-related cost of electrification but this comes with the price of an infrastructure that needs to be built and maintained. In order to design the ICPT infrastructure and calculate the cost of construction and operation, certain assumptions have to be made with respect to the vehicle specifications, the specification of the charging system itself and the cost of integration into the existing road infrastructure. The objective of this paper is to provide a thorough analysis of the cost associated with the implementation of a dynamic ICPT infrastructure to support the operation of electrified vehicles and to present transportation agencies a business model that can provide a starting point for the development of a new EV infrastructure.

Estimation of Pavement and Bridge Damage Costs Caused by Overweight Trucks

Abstract: This study adopted a damage quantification framework to estimate bridge and pavement damage caused by overweight trucks. The framework was applied to estimate unit overweight truck damage costs for the highway system maintained by the South Carolina Department of Transportation. The analysis revealed that pavement and bridge damage increased significantly when trucks were above legal weight limits. Tradeoffs between the most common overweight truck fee types were estimated to examine their relative efficacy. The study found the axle-based damage cost recovery fee for the additional per trip damage cost above the legal weight limit for an overweight truck loaded up to the maximum overweight limit. The fee varied between $14 and $165 per trip, depending on the type of overweight truck. The flat damage cost recovery fee was $55 per trip for all overweight trucks (about two times the current flat damage fee in South Carolina). The study revealed that ignoring the axle distribution in the flat damage cost reco...

Energy Consumption Reduction Strategies for Plug-In Hybrid Electric Vehicles with Connected Vehicle Technology in Urban Areas

Abstract: Automobile manufacturers have introduced plug-in hybrid electric vehicles (PHEVs) to reduce fossil fuel consumption. This paper details three optimization strategies that can be used to minimize the energy consumption of PHEVs further through an information exchange between PHEVs and infrastructure agents supported by connected vehicle technology (CVT). An earlier study focused on a freeway scenario. The study reported here developed strategies for an urban scenario with frequent stop-and-go conditions. Three strategies were considered on the basis of different types of information availability with the use of CVT. Only signal timing information was available in Strategy 1; only headway information was available in Strategy 2; and both signal timing and headway information were available in Strategy 3. The performance of PHEVs that received no real-time information was used as the base case for Strategies 1, 2, and 3 to evaluate each strategy. The optimization strategies resulted in energy consumption sav...

A network wide simulation strategy of alternative fuel vehicles

Abstract: This paper presents an integrated simulator “CUIntegration” to evaluate routing strategies based on energy and/or traffic measures of effectiveness for any Alternative Fuel Vehicles (AFVs). The CUIntegration can integrate vehicle models of conventional vehicles as well as AFVs developed with MATLAB-Simulink, and a roadway network model developed with traffic microscopic simulation software VISSIM. The architecture of this simulator is discussed in this paper along with a case study in which the simulator was utilized for evaluating a routing strategy for Plug-in Hybrid Electric Vehicles (PHEVs) and Electric Vehicles (EVs). The authors developed a route optimization algorithm to guide an AFV based on that AFV driver’s choice, which included; finding a route with minimum (1) travel time, (2) energy consumption or (3) a combination of both. The Application Programming Interface (API) was developed using Visual Basic to simulate the vehicle models/algorithms developed in MATLAB and direct vehicles in a roadway network model developed in VISSIM accordingly. The case study included a section of Interstate 83 in Baltimore, Maryland, which was modeled, calibrated and validated. The authors considered a worst-case scenario with an incident on the main route blocking all lanes for 30 min. The PHEVs and EVs were represented by integrating the MATLAB-Simulink vehicle models with the traffic simulator. The CUIntegration successfully combined vehicle models with a roadway traffic network model to support a routing strategy for PHEVs and EVs. Simulation experiments with CUIntegration revealed that routing of PHEVs resulted in cost savings of about 29% when optimized for the energy consumption, and for the same optimization objective, routing of EVs resulted in about 64% savings.

Best Practices for Procurement and Management of Professional Services Contracts

Abstract: The ongoing climate of fiscal limitations coupled with increased infrastructure demand poses significant challenges for state DOTs. Most face continuing pressure to meet the increasing infrastructure demands of their state with limited resources. Professional services consultant procurement and contract administration are significant and important components of the infrastructure delivery process. How these professional services contracts are procured and managed can have a substantial impact on organizational resources, personnel efficiency and effectiveness, consultant performance, and infrastructure cost and quality. This paper investigates the current practice of the departments of transportation in seven states, interviews subject matter experts, evaluates scholarly work by industry and academic professionals, and examines previous studies to develop 12 best practices for the procurement and contract administration of professional services consultants. The study identified 12 best practices i...

Development of a Professional Services Management Training Program

Abstract: The lack of training programs in systems that allow insufficient references in departments of transportation (DOTs) can create a procurement and administration process that is inefficient, inconsistent, and ineffective. Public agency activities related to contracts must be efficient, fair, and consistent to maintain compliance with state and federal policies. The South Carolina DOT identified a need to develop a comprehensive training program for professional service contract managers to support consistent and efficient execution of department contracts. The objectives of this study were to develop a training program for South Carolina DOT professional services contract managers and to evaluate the training program for statewide adoption. The study resulted in the development of a comprehensive training program to ensure that current and future South Carolina DOT contract managers across the department procure and administer professional services contracts with consistency and effectiveness. Lessons learn...

ITS for One of the Most Congested Cities in the Developing World?Dhaka Bangladesh: Challenges and Potentials [ITS in Developing Countries]

Abstract: Transportation planners from Dhaka city always confront the paradox of adjusting an ever increasing travel demand with the limited available resources. Thus, Dhaka city motorists suffocate while they idle in the intolerable gridlock for hours. ITS applications can play an active role in mitigating this gridlock by dramatically changing the existing problems of limited roadway capacity, vulnerable safety and neglected public transportation system. However, after carefully scrutinizing the prevailing traffic conditions and their interlinked problems, the authors have identified various potential ITS applications despite limited active ITS applications in Dhaka city. Observations indicate that rather than perpetuating the concept of ITS in Dhaka city as mythological, it is indeed a cost-effective method for both the users and the government for traffic management.

Impact of Minimum Driveway Spacing Policies on Safety Performance: An Integrated Traffic Micro-Simulation and Automated Conflict Analysis

Abstract: A key strategy for successful access management is the adoption of driveway spacing guidelines that consider both safety and operations. The goal is to provide sufficient distance from one driveway to the next so that drivers can perceive and react to the conditions at each potential conflict point in succession. State DOTs across the country have adopted different driveway spacing standards that vary according to the access class and characteristics of the adjacent roadway, such as type of roadway, posted speed limit, and traffic volume. Utilizing the VISSIM microscopic traffic simulation tool and FHWA's Surrogate Safety Assessment Model (SSAM), this research examined safety implications of four different driveway spacing policies representing 13 states. The analysis involved calibrating the VISSIM model for an arterial roadway corridor in West Columbia, SC, and then using the calibrated model to simulate various operational changes to the corridor, including speed limits, traffic volumes, and the associated minimum driveway spacing criteria for the four different policies. SSAM was used to analyze vehicle trajectories derived from VISSIM to determine the number of conflict points. Experimental results indicate that posted speed limit and traffic volume are the primary impact factors for driveway safety, and thus, these parameters should be considered in establishing minimum driveway spacing. Findings from this study indicate that there are significant differences in safety impacts between the different driveway spacing policies adopted by various state DOTs.

A Parameter Estimation and Calibration Method for Car-Following Models

Abstract: Microscopic roadway traffic simulators, which attempt to mimic real-world driver behaviors, are based on car-following models. The accuracy and reliability of microscopic traffic simulation models are greatly dependent on the calibration of car-following models, which requires a large amount of real world vehicle trajectory data. In the last few decades, many car-following models have been developed; however, studies are still needed to improve their accuracy and reliability. In this research, the authors developed a process to apply a stochastic calibration method with appropriate regularization to estimate the distribution of parameters for car-following models. The calibration method is founded on the Markov Chain Monte Carlo (MCMC) simulation that uses the Bayesian estimation theory. This research includes a case study, which is based on the Linear (Helly) model with a different number of vehicle trajectories in a highway network. The stochastic approach facilitated the calibration of car-following models more realistically than the deterministic method, as the deterministic algorithm can easily get stuck at a local minimum. The Bayesian approach provided better results in terms of the cost function than the deterministic optimization algorithm. With the Bayesian approach, the average mean square error per vehicle is decreased with increased number of vehicles. Analysis also revealed that the Bayesian approach predicted drivers’ acceleration and deceleration profile more closely compared to the deterministic approach considered in this study. The positive validation outcomes suggest potential efficacy of the calibration approach presented in this paper.

A Tradeoff Analysis for Different Damage Fee Structures for Offsetting Overweight Truck Damage Costs

Abstract: The rapid growth of freight traffic is now taxing a significant number of the United States national freight corridors. This additional demand accompanied by trucks over legal limits has been accelerating infrastructure deterioration at a faster rate than anticipated. Concurrent with this demand, sufficient revenues to offset such damage on freight corridors are not collected by the states. To develop effective policies to overcome this situation, decision makers (DMs) must develop policy options considering multiple conflicting objectives simultaneously. In this study, a multiobjective analysis approach is applied to address the conflicting objectives associated with overweight freight truck mobility and to identify best possible permit fee options as well as generate detailed tradeoffs between these options. In this paper, a case study is presented with two objectives: the minimization of unpaid damage associated with overweight freight trucks and the minimization of overweight damage fee. A set of overweight fee options is generated with the associated tradeoffs. The tradeoff analysis reveals that increasing the flat overweight damage fee by $1 from $40 would reduce the unpaid damages to bridges and pavement equivalent to $14.8 million annually in South Carolina with a high elasticity of demand. Similarly, in the axle-based fee structure, increasing the axle-based overweight damage fee by on average $1 from the average axle-based damage fee of $40 would reduce the unpaid damages to bridges and pavement equivalent to $14.2 million annually in South Carolina. These types of tradeoff analyses provide valuable information to DMs to select an appropriate type and level of fee structure for overweight trucks.

Using Inquiry to Expose Undergraduates to ITS

Abstract: In our rapidly evolving world, asking the right questions and properly defining problem boundaries is paramount to successful engineering design. These practices are especially vital for Intelligent Transportation Systems (ITS), which can address a wide range of transportation problems, but which also can exacerbate these same problems. For example, ITS solutions that address the narrowly defined problem of improving traffic flow in an urban area can lead to more regional sprawl, and therefore more traffic and so on-reinforcing a negative feedback loop with ugly results. If the problem is instead framed as trying to reduce commuting times, entirely different and more sustainable ITS solutions may be found. The best planners proceed with caution to avoid prescribing solutions to perceived problems; instead, they take care to understand challenges to urban mobility and the propagating impacts that different development strategies may have. Genuine inquiry, the act of asking questions, ought to be a foundation of engineering education. Indeed, an accumulating amount of engineering education research makes the benefits of such active learning techniques impossible to ignore. Inquiry-based learning begins by posing questions, problems or scenarios in lieu of simply presenting established facts or portraying an existing path to knowledge. It places students' questions, ideas and observations at the center of the learning experience. As students engage with challenges and questions, they achieve higher levels of learning-past the stage of memorizing and reciting data-to more sophisticated methods of analysis, synthesis, and application. The instructor's role is to creatively combine best practices, including explicit instruction, and small-group and guided learning in an attempt to build on students' interests and ideas, ultimately moving students forward in their paths of intellectual curiosity and understanding. This inquiry-based approach is used to introduce a team of Clemson students to the principles and applications of ITS in developing nations.