Civil Engineering Masters Theses Collection

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An Evaluation of Driver Comprehension and Behavior at Pedestrian Hybrid Beacon (PHB) Intervals
(2024-09) Caggiano, Angelina
Pedestrian Hybrid Beacons (PHB) offer a unique opportunity to facilitate pedestrian crossings at midblock crossing locations. The tri-signal head design includes signal sections displaying two red indications above a single yellow indication and includes 5 distinct phasing intervals previously unfamiliar to drivers: Dark, Flashing Yellow, Solid Yellow, Solid Red, and Flashing Red. Each interval is intended to communicate some aspect of needing to stop, slow or remain cautious to drivers; however, the PHBs effectiveness is only realized if drivers both comprehend the meaning of the specific interval and respond appropriately. The objective of this thesis is to examine the extent to which drivers comprehend each PHB interval and yield to pedestrians. Results from a driver comprehension survey investigates driver's understanding of PHB intervals: Dark, Flashing Yellow, Solid Yellow, Solid Red, and Flashing Red. The survey’s results provide evidence that driver perceptions are inconsistent with recommended actions in PHB infographics and user guides. Natural field observations were collected from ten PHB installations throughout Massachusetts and included at least 3 hours of video data or 50 actuated crossings. A developed video reduction method was employed to record the number of vehicles that fully stopped, partially stopped, or drove through each PHB interval during a pedestrian crossing event. This research provides insight on driver’s behavior during each of the intervals and their correlation to pedestrian crossing behavior, such as the interval when the pedestrian decides to cross. These results provide the foundation for specific roadway design guidance, such as speed, vehicle and pedestrian volumes, number of lanes, and PHB push button proximity based on the degree to which each attribute impacts driver yielding rates. Furthermore, the results of this study provide direct guidance on each PHB interval for use in educational materials, implementation strategies, and further design of PHB crossings such as interval timing and distance to the pushbutton.
A Typology-Informed Season-Aware Transit Trip Chaining Framework
(2024-05) Mohammed, Mohammed A.
Regional transit systems often lack the resources for comprehensive data collection systems such as smart cards, which hinders their ability to understand passenger travel patterns and optimize service. This thesis addresses this gap by developing an innovative trip chaining framework that uses boarding-only data from mobile ticketing systems, a more accessible and cost-effective alternative. The framework incorporates passenger typology, seasonality, and spatial error correction to address the unique challenges posed by this data. First, spatiotemporal passenger types are identified through clustering analysis of mobile ticketing activations, revealing distinct travel behaviors and patterns. These types inform the calibration of type-specific and season-aware parameters for boarding, alighting, and transfer inferences within the trip chaining framework. Additionally, a gradient boosting machine model is trained to learn the spatial error structure of initial predictions and refine the model's accuracy. The results demonstrate that the integration of passenger typology, seasonality, and spatial error correction significantly enhances the accuracy of trip chaining predictions. Notably, incorporating spatial error correction through gradient boosting leads to a substantial improvement in model performance, with a 70% reduction in mean absolute error. Furthermore, the passenger typology offers valuable insights into travel characteristics of different user groups, facilitating more targeted planning efforts. This framework provides regional transit planners with a powerful tool to extract valuable insights from limited data sources. By understanding passenger travel patterns and demand, transit agencies can optimize service, allocate resources efficiently, and ultimately promote greater public transportation usage.
Bicyclist Behavior at Intersections: A Study of Two-Stage turn Queue Boxes in Massachusetts
(2024-05) Ahammed, Dewan Tanvir
Two-stage turn queue boxes (TSTQB) are innovative bicycle infrastructure treatments implemented to enhance bicyclist safety and comfort. These boxes provide an alternative for bicyclists to make left turns from right-side cycle tracks or bike lanes and right turns from left-side cycle tracks or bike lanes at multi-lane intersections. The aim of this treatment is to improve bicyclist visibility and predictability and protect bicyclists' left-turning movements, thus reducing crash risk. Although these solutions are being implemented at various intersections throughout the USA, research on the behavior of bicyclists in the presence of TSTQB is limited. There is a need to investigate the way TSTQBs are used and understand which design characteristics may influence their effectiveness in improving bicyclist safety. This thesis addresses this research gap by collecting real-world data from six intersections in the Greater Boston area featuring TSTQBs and providing an in-depth examination of left-turning bicyclist behavior in the presence of such treatments. A comprehensive inventory of TSTQBs in Massachusetts is first presented. The inventory has been collected through manual observations from Google Maps. The analysis focuses on understanding bicyclists’ positioning and usage rates of TSTQBs in the presence of left-turn phases, dedicated left-turn lanes, and bike boxes. Finally, correlations between intersection and TSTQB design characteristics and bicyclist behavior are examined. The final outcomes of this study can serve as a basis for informing design standards and educational initiatives that aim to enhance bicyclist safety at signalized intersections.
Modeling Energy Consumption for Sustainable Urban Rail Transit Systems
(2024-05) Han, Zhuo
Rapid transit systems are essential components of urban public transportation networks, significantly impacting personal mobility, energy use, and environmental costs. To address the need for effective planning and to provide critical consumption metrics, we developed models using operational and ridership data from the Massachusetts Bay Transportation Authority’s rapid transit system, incorporating ambient temperature to predict electricity consumption accurately. These models, which include a multiple linear regression (MLR) and a random forest (RF), were trained with data from 2019 and tested with data from 2020. They explained between 93% and 95% of the variance, demonstrating high accuracy with RMSE values of 2.7MWh and 2.94MWh, and MAPE values of 4.68% and 5.01%, respectively. Building on this framework, we proposed a machine learning model to assess line-specific contributions to energy within Boston's complex rail transit network, which consumes 422 GWh of electricity annually at a cost of $38 million. By integrating line-specific variables related to train movement and operations, our enhanced model achieved an R2 of 0.91, providing a nuanced understanding of the relationships between energy consumption, train movement, ridership, and weather variables. This model allows for hour-level analysis of energy contributions by different lines, with the Red Line being a significant contributor. Additionally, we explored the impacts of COVID-19 on the transit system, examining changes in ridership, energy consumption, costs, and train movements before and during the pandemic. The findings indicate that our models remain robust and perform well despite the significant disruptions caused by the pandemic. This research supports future planning, disaster response, and real-time energy monitoring, offering valuable insights for energy and cost reduction strategies in urban rail systems.
An Evaluation of Simulation Models To Assess Travel Delay In Work Zones
(2008) Wu, Fan
About 20 percent of the U.S. National Highway System is under construction during the peak summer roadway season. Fifty percent of all highway congestion is attributed to nonrecurring conditions and work zones are estimated to account for nearly 24 percent of nonrecurring delay. Work zones account for two percent of roadway crashes and more than 1,000 fatalities per year. Motorists across the United States have increasingly voiced their displeasure with work zones and the associated delay. This has posed a challenge to transportation officials and contractors as they are faced with finding ways to reduce work zone delay. A key to addressing this challenge to minimize motorist delay during construction and maintenance operations is to recognize these impacts well in advance. In order to meet this challenge, work zone strategy evaluations are necessary to understand the type, severity, and extent of impacts associated with various strategies. One major tool used to aid in conducting these evaluations is computer simulation. There are many simulation packages in existence, some of which are designed specifically for work zone analysis. These packages include, for example, QUEWZ, QuickZone, and CA4PRS. This research focuses on the evaluation of these three simulation packages along work zones located on four interstate highway segments on I-91 and I-95 in New England. The evaluation consists of comparing simulation results to field observations in the work zones. The queue lengths estimated by QuickZone and QUEWZ are compared to queue lengths observed in the work zone. Maximum rehabilitation production rates estimated by CA4PRS will be compared to actual production rates recorded in the work zone. This evaluation will allow for a determination to be made as to whether or not these simulation packages produce accurate estimates. In addition to accuracy, the evaluation also sheds light on the user-friendliness of each simulation model as well as other parameters such as data requirements and analysis time. Major results of this evaluation include: • QUEWZ and QuickZone are user-friendly work zone simulation models. • The estimations of queue length provided by QuickZone and QUEWZ for the four sites considered in this research were found to be comparable to the field observations. • CA4PRS is a user-friendly simulation model. However, the data required to perform an analysis is not as always easy to obtain. In addition, these simulated results of maximum rehabilitation production rates are not easily compared to observed data which are not typically available. This research should be helpful to guide state and local officials in New England in the selection of simulation models to assess work zone strategies for roadway reconstruction and rehabilitation projects in New England.
Anchorage of Carbon Fiber Reinforced Polymers to Reinforced Concrete in Shear Applications
(2008) Niemitz, Carl W
Within the past few decades a new technology has emerged using Fiber Reinforced Polymers (FRP) to rehabilitate and retrofit reinforced concrete (RC) structures. In FRP shear strengthening applications it is largely recognized that debonding is the prevailing failure mode. FRP debonding typically occurs prematurely as a brittle failure mode that limits the efficiency of the strengthening technique. No systematic tests have been conducted to investigate the capacity gained by anchoring FRP laminates to RC elements in shear applications. The objective of this research program was to study the effects of anchoring FRP laminates to RC members with FRP anchors thereby delaying or potentially eliminating debonding of FRP sheets from the concrete surface. FRP anchors used in this research were made from fibers used as part of FRP sheets that get bundled into a roll with a fanned upper end of the anchor allowing the fibers to be splayed over the FRP sheet. A single shear pull test experiment was developed to study the effects of anchoring FRP laminates using FRP anchors with varying anchor diameters, lengths, and patterning. The results of the experimental portion of this research project were used in combination with finite element analyses to develop models for anchored FRP sheets that can be used in design of shear strengthening applications.
Evaluating At-Grade Rail Crossing Safety along the Knowledge Corridor in Massachusetts
(2013-02) Horan, Timothy P
Highway-rail grade crossings are safer than ever, but collisions between motor vehicles and trains persist. Some collisions could be prevented by actively maintaining such grade crossings, yet many at-grade rail crossings are only evaluated following collisions. Those crossings that experience no collisions may go decades without being inspected. In recent years, the Congress has allocated funds for a national High-Speed Intercity Passenger Rail program, and it is in the public’s interest for state road/highway agencies to inspect all highway-rail crossings in high-speed rail corridors to ensure that the warning systems in place are commensurate with the crossings’ needs. The objectives of this research are to a) determine the adequacy of traffic control devices at highway-rail grade crossings along the restored Vermonter tracks in Massachusetts; and b) to recommend crossings for closure and/or grade separation if it is determined that the traffic control devices are inadequate at an intersection. The major findings of this paper are that a majority of the at-grade rail crossings need some improvements to be in compliance with MUTCD standards. Additionally, four at-grade crossings are identified for closure, grade-separation, and/or additional traffic control devices beyond MUTCD standards.
Spatial and Temporal Correlations of Freeway Link Speeds: An Empirical Study
(2012-09) Rachtan, Piotr J
Congestion on roadways and high level of uncertainty of traffic conditions are major considerations for trip planning. The purpose of this research is to investigate the characteristics and patterns of spatial and temporal correlations and also to detect other variables that affect correlation in a freeway setting. 5-minute speed aggregates from the Performance Measurement System (PeMS) database are obtained for two directions of an urban freeway – I-10 between Santa Monica and Los Angeles, California. Observations are for all non-holiday weekdays between January 1st and June 30th, 2010. Other variables include traffic flow, ramp locations, number of lanes and the level of congestion at each detector station. A weighted least squares multilinear regression model is fitted to the data; the dependent variable is Fisher Z transform of correlation coefficient. Estimated coefficients of the general regression model indicate that increasing spatial and temporal distances reduces correlations. The positive parameters of spatial and temporal distance interaction term show that the reduction rate diminishes with spatial or temporal distance. Higher congestion tends to retain higher expected value of correlation; corrections to the model due to variations in road geometry tend to be minor. The general model provides a framework for building a family of more responsive and better-fitting models for a 6.5 mile segment of the freeway during three times of day: morning, midday, and afternoon. Each model is cross-validated on two locations: the opposite direction of the freeway, and a different location on the direction used for estimation. Cross-validation results show that models are able to retain 75% or more of their original predictive capability on independent samples. Incorporation of predictor variables that describe road geometry and traffic conditions into the model works beneficially in capturing a significant portion of variance of the response. The developed regression models are thus transferrable and are apt to predict correlation on other freeway locations.
An Optimal Adaptive Routing Algorithm for Large-scale Stochastic Time-Dependent Networks
(2012-09) Ding, Jing
The objective of the research is to study optimal routing policy (ORP) problems and to develop an optimal adaptive routing algorithm practical for large-scale Stochastic Time-Dependent (STD) real-life networks, where a traveler could revise the route choice based upon en route information. The routing problems studied can be viewed as counterparts of shortest path problems in deterministic networks. A routing policy is defined as a decision rule that specifies what node to take next at each decision node based on realized link travel times and the current time. The existing routing policy algorithm is for explorative purpose and can only be applied to hypothetical simplified network. In this research, important changes have been made to make it practical in a large-scale real-life network. Important changes in the new algorithm include piece-wise linear travel time representation, turn-based, label-correcting, criterion of stochastic links, and dynamic blocked links. Complete dependency perfect online information (CDPI) variant is then studied in a real-life network (Pioneer Valley, Massachusetts). Link travel times are modeled as random variables with time-dependent distributions which are obtained by running Dynamic Traffic Assignment (DTA) using data provided by Pioneer Valley Planning Commission (PVPC). A comprehensive explanation of the changes by comparing the two algorithms and an in-depth discussion of the parameters that affects the runtime of the new algorithm is given. Computational tests on the runtime changing with different parameters are then carried out and the summary of its effectiveness are presented. To further and fully understand the applicability and efficiency, this algorithm is then tested in another large-scale network, Stockholm in Sweden, and in small random networks. This research is also a good starting point to investigate strategic route choice models and strategic route choice behavior in a real-life network. The major tasks are to acquire data, generate time-adaptive routing policies, and estimate the runtime of the algorithm by changing the parameters in two large-scale real-life networks, and to test the algorithm in small random networks. The research contributes to the knowledge base of ORP problems in stochastic time-dependent (STD) networks by developing an algorithm practical for large-scale networks that considers complete time-wise and link-wise stochastic dependency.
Performance Evaluation Of Existing Steel And Concrete Girder Bridges Through Non-destructive Live-load Testing
(2008) Jeffrey, Andrew E
Evaluating and Modeling Traveler Response to Real-Time Information in the Pioneer Valley
(2012-05) De Ruiter, Tyler
This study used focus groups and surveys to provide a comprehensive evaluation of the Regional Traveler Information Center (RTIC) at UMass Amherst. The evaluation was completed by obtaining the awareness, usage, and perceived effectiveness of RTIC’s information by residents in the Pioneer Valley. It was found that awareness of RTIC is limited due to its lack of advertisement. Usage is focused primarily on its webcams and advisory information. Surveys showed that participants perceive RTIC to be useful, even though they may never have seen the information before (the survey provided a chance for them to become familiar with the service). Revealed preference data were collected regarding the travelers' most memorable instances where real-time traffic information was provided. A binary logit model of a traveler's switch decision (route, departure time, mode, destination, trip cancellation, or combinations of them) with real-time traffic information was specified and estimated. It was found that travelers have an increasing tendency to switch away from the original option when the resulting delay caused by congestion increases. Receiving congestion and crash information also provided a tendency to take an alternative travel method. It was found that males tend to switch more often than females, and young individuals switch less often.
Probabilistic Analysis of Offshore Wind Turbine Soil-Structure Interaction
(2012-05) Carswell, Wystan
A literature review of current design and analysis methods for offshore wind turbine (OWT) foundations is presented, focusing primarily on the monopile foundation. Laterally loaded monopile foundations are typically designed using the American Petroleum Institute (API) p-y method for offshore oil platforms, which presents several issues when extended to OWTs, mostly with respect to the large pile diameters required and the effect of cyclic loading from wind and waves. Although remedies have been proposed, none have been incorporated into current design standards. Foundations must be uniquely designed for each wind farm due to extreme dependence on site characteristics. The uncertainty in soil conditions as well as wind and wave loading is currently treated with a deterministic design procedure, though standards leave the door open for engineers to use a probability-based approach. This thesis uses probabilistic methods to examine the reliability of OWT pile foundations. A static two-dimensional analysis in MATLAB includes the nonlinearity of p-y soil spring stiffness, variation in soil properties, sensitivity to pile design parameters and loading conditions. Results are concluded with a natural frequency analysis.
User Equilibrium in a Disrupted Network with Real-Time Information and Heterogeneous Risk Attitude
(2012-05) Pothering, Ryan J
The traffic network is subject to random disruptions, such as incidents, bad weather, or other drivers’ random behavior. A traveler’s route choice behavior in such a network is thus affected by the probabilities of such disruptions, his/her attitude towards risk, and real-time information on revealed traffic conditions that could potentially reduce the level of uncertainty due to the disruptions. As the road network’s performance is de-termined collectively by all travelers’ choices, it is also affected by these factors. This thesis features the development of a multi-class user equilibrium model based on hetero-geneous risk attitude distributions and a user equilibrium model based on various disrup-tion probabilities and information penetration rates that can be used to perform sensitivity analyses for a traffic network. The method of successive average (MSA) is used to solve for the equilibrium conditions. Laboratory experimental data are used to calibrate the risk attitude model. A sample sensitivity analysis is performed to show the disruption and in-formation penetration effects on network performance. Initial calibrations show promis-ing results for route flow predictions in a congested network with respect to heterogene-ous attitude. With respect to disruption probability and information access, having too v high information penetration will not improve the network’s performance, while having a small disruption probability can improve traffic conditions in the network
Automated Enforcement Using Dedicated Short Range Communication
(2012-05) Kim, Gilbert
This thesis presents a set of system algorithms and a feasibility analysis of an automated enforcement system that uses dedicated short-range communication with an emphasis on seatbelt and speed enforcement. The current seatbelt and speed enforcement limitations and disadvantages can be overcome because future vehicles will be equipped with devices that can be used to communicate with other vehicles or the traffic infrastructure. One limitation of the current seatbelt enforcement system is that it relies only on human vision. Today’s automated photo speed enforcement also has the following major limitations and disadvantages: fixed position enforcement, system installation and maintenance costs, enforcement based only on spot speed, sensitivity to lighting conditions, and vulnerability to sprays and obstructions that might block the license plates. This thesis proposes an automated enforcement system that uses wireless communication (IEEE 802.11p protocol), which can resolve all of the above-mentioned problems and is also more efficient, accurate, and cost effective.
Evaluation of Live-Load Distribution Factors (LLDFs) of Next Beam Bridges
(2012-05) Singh, Abhijeet Kumar
A new precast-prestressed cross section was recently developed by a consortium of engineers from the six New England states, New York and members of the northeast region of PCI. The northeast extreme Tee (NEXT) beam is efficient for medium Bridge spans (50 to 80 ft long). Field formwork savings are introduced by having a flange cast integrally during fabrication of the beams at the precasting plant. Job safety is increased because a working platform is created. The flange width of the NEXT Beams can be adjusted during fabrication to accommodate roadways of different widths and skew angles. Because the section is new with complexity in its shape, the present design guidance cannot be used to evaluate LLDFs for NEXT beams within the context of the AASHTO LRFD. In particular, the use of live-load distribution factors (LLDFs) equations in LRFD for NEXT beams is not straightforward. The distance between the beam webs is variable depending on whether it is measured within a beam module or between adjacent modules. In absence of detailed information a PCI technical committee evaluated LLDFs (through AASHTO 2010 Bridge specification) for the NEXT beams used in the Brimfield Bridge by two different approaches and found one of them conservative. The conservative approach was single stem which uses the average spacing (between webs ([S1+S3]/2)) for use in the LLDF equations.. The committee expressed concerns about whether trends of LLDFs would be similar for other parametric sets, and would like to standardize the methodology for the Bridge projects in Massachusetts with NEXT beam as the girder. To verify the conservativeness of single stem methodology (for the evaluation of LLDFs) for other parameters this research project was initiated. LLDFs are evaluated based on the two approaches and compared with the LLDFs obtained through finite element modeling. The results of 40-3D finite element models have been used to compare the LLDFs obtained from AASHTO 2010 Bridge design specification. The results were also used to compare different parameters that affect LLDFs of NEXT beams including span, skew angle, and beam end fixity. The finite element models were created using a Bridge prototype that is being instrumented for future field verification of the analyses. The models were created using frame elements for the beams and shell elements for the cast in place deck. The integral abutment and foundation of the Bridges was included in the models in which piles are created using frame elements and abutments are created using shell elements. The results indicate that the approach taken for the design of NEXT beams is in general conservative for interior girders of the Bridge. On the contrary such the adopted approach was not yielding the higher value of LLDFs. The variation in strains due to losses are compared by two methods (strains variation obtained from field data and strain variation obtained based on AASHTO equation of losses) to verify the AASHTO equation of losses.
Material Characterization and Computational Simulation of Steel Foam for Use in Structural Applications
(2012-05) Smith, Brooks H
Cellular metals made from aluminum, titanium, or other metals are becoming increasingly popular for use in structural components of automobiles, aircraft, and orthopaedic implants. Civil engineering applications remain largely absent, primarily due to poor understanding of the material and its structural properties. However, the material features a high stiffness to weight ratio, excellent energy dissipation, and low thermal conductivity, suggesting that it could become a highly valuable new material in structural engineering. Previous attempts to characterize the mechanical properties of steel foam have focused almost exclusively upon uniaxial compression tests, both in experimental research and in computational simulations. Further, computational simulations have rarely taken the randomness of the material’s microstructure into account and have instead simplified the material to a regular structure. Experimental tests have therefore been performed upon both hollow spheres and PCM steel foams to determine compressive, tensile, and shear properties. Computational simulations which accurately represent the randomness within the microstructure have been validated against these experimental results and then used to simulate other material scale tests. Simulated test matrices have determined macroscopic system sensitivity to various material and geometrical parameters.
An Analysis Of The Saftey Effects Of Crosswalks With In-pavement Warning Lights
(2007) Gadiel, George
Pedestrian safety is among one of the largest concerns in the transportation profession. Many treatments have been developed and implemented to improve pedestrian safety. This current research focuses on the efficiency of in-pavement warning lights systems and involves multiple objectives. The primary objective is to evaluate the yielding rates and crosswalk usage of existing and proposed in-pavement lights systems with comparisons including before and after data through a case study approach. A secondary objective is to evaluate where drivers are looking when they approach in-pavement lights systems and develop a model to evaluate their behavior. The research described herein formulated these objectives into two research hypotheses and used statistical evaluation methodologies to provide quantitative and/or qualitative responses to the developed hypotheses. Data on pedestrian and driver behavior in the field, and the interaction between, them was collected using video camera technology in the Amherst, Massachusetts area. Data regarding drivers scan patterns during the approach to a crosswalk with in-pavement warning light system was collected using a driving simulator and an eye tracker. In total, 1,949 non-staged pedestrians and 606 staged pedestrians were observed crossing at the seven crosswalk locations in the field experiment and a total of 32 drivers participated in 576 crosswalk scenarios in the driving simulator evaluation. The field evaluation resulted in increased yielding rates and crosswalk usage after installation of in-pavement warning lights, while driving simulator evaluation resulted in drivers not becoming accustomed to scanning for lights instead of a pedestrian. Recommendations include installation of in-pavement warning lights at traditional, midblock crosswalks and continued exploration of all crosswalks in the driving simulator evaluation.
Driver Dynamics and the Longitudinal Control Model
(2012-05) Leiner, Gabriel G.
Driver psychology is one of the most difficult phenomena to model in the realm of traffic flow theory because mathematics often cannot capture the human factors involved with driving a car. Over the past several decades, many models have attempted to model driver aggressiveness with varied results. The recently proposed Longitudinal Control Model (LCM) makes such an attempt, and this paper offers evidence of the LCM's usefulness in modeling road dynamics by analyzing deceleration rates that are commonly associated with various levels of aggression displayed by drivers. The paper is roughly divided into three sections, one outlining the LCM's ability to quantify forces between passive and aggressive drivers on a microscopic level, one describing the LCM's ability to measure aggressiveness of platoons of drivers, and the last explaining the meaning of the model’s derivative. The paper references some attempts to capture driver aggressiveness made by classic car-following models, and endeavors to offer some new ideas in study of driver characteristics and traffic flow theory.
New Technologies in Short Span Bridges: A Study of Three Innovative Systems
(2012-05) Lahovich, Andrew
Short span bridges are commonly used throughout the United States to span small waterways and highway overpasses. New technologies in the civil engineering industry have aided in the creation of many unique designs of these short span highway bridges in efforts to decrease construction cost, decrease maintenance costs, increase efficiency, increase constructability, and increase safety. Three innovative systems, the Integral Abutment Bridge, “Bridge-in-a-Backpack”, and the Folded Plate Girder bridge will be analyzed to study how the bridges behave under various types of loading. Detailed finite element models were created for integral abutment bridges of varying geometry. These models are used to study how the live load distribution transversely across the bridge is effected by varying geometric properties and varying modeling techniques. These models will also be used to determine live load distribution factors for the integral abutment bridges and compare them to current American Association of State Highway and Transportation Officials specifications. The “Bridge-in-a-Backpack” and the Folded Plate Girder bridges were each constructed with a variety of instruments to measure the bridge movements. Readings from these instruments are used to determine the bridge response under various loading conditions. Bridges were analyzed during their construction process, during static live load testing, and during long term seasonal changes. The results from these studies will aid in the refinement of these innovative designs.
Vehicle Miles Traveled (vmt) Fee Financing Alternatives: Lessons Learned and Future Opportunities
(2012-05) Costa, Ashley L
State Departments of Transportation (DOTs) today are seeking financing alternatives so that transportation infrastructure investments can become less dependent on the amount of fuel U.S. drivers consume. Because the fuel tax is no longer viewed as a sustainable and stable option, other financing alternatives are being considered. One such alternative includes the vehicle miles traveled (VMT) fee. Examples of such VMT fee alternatives include: 1) collection using an onboard diagnostic system (OBD), 2) collection at the fuel pump using an OBD in conjunction with GPS technology, and 3) collection at a vehicle inspection station using the OBD. This proposed research has two primary objectives: 1) to conduct a comparative review of VMT fee alternatives and their data collection methods, payment collection processes, expected costs and revenues, and anticipated challenges; and 2) to examine the suitability of these VMT fee alternative for consideration in Massachusetts. The major results and conclusions are the fuel tax, if increased and reviewed annually, is a viable short term solution and that a VMT fee should be considered further as part of a long term strategy. It is expected that the results of this research will be of interest to Federal and State DOT personnel and policy makers.

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