Automated Electric Transportation (AET) proposes a system of automated platooning vehicles electrically powered by the roadway via wireless inductive power transfer. This has the potential to provide roadway transportation that is less congested, more flexible, cleaner, safer, and faster than the current system. The focus of this research is to show how platooning can be accomplished in a safe manner and what capacities such an automated platooning system can achieve. To accomplish this, first two collision models are developed to show the performance of automated platoons during an emergency braking scenario: a stochastic model coded in Matlab/Simulink and a deterministic model with closed-form solutions. The necessary parameters for safe platooning are then defined: brake variances, communication delays, and maximum acceptable collision speeds. The two collision models are compared using the Student's t-test to show their equivalence. It is shown that while the two do not yield identical results, in most cases the results of the deterministic model are more conservative than and reasonably close to the results of the deterministic model. The deterministic model is then used to develop a capacity model describing automated platooning flow as a function of speed and platoon size. For conditions where platooning is initially unsafe, three amelioration protocols are evaluated: brake derating, collaborative braking, and increasing the maximum acceptable collision speed. Automated platooning flow is evaluated for all of these scenarios, compared both with each other and with traditional roadway flow patterns. The results of these models show that when platooning is initially safe, very high vehicle flows are possible: for example, over 12,000 veh/hr for initial speeds of 30 m/s and 10 vehicle platoons. Varying system paramaters can have large ramifications for overall capacity. For example, autonomous (non-platooning) vehicles do not promise anywhere near this level, and in many cases struggle to approach the capacity of traditional roadways. Additionally, ensuring safety under an emergency braking standard requires very small communication delays and, most importantly, tight braking variances between the vehicles within a platoon. As proposed by AET, a single type of electric vehicle, combined with modern wireless communications, can make platooning safer than was previously possible without requiring amelioration. Both brake derating and collaborative braking can make platooning safer, but they reduce capacity and may not be practical for real-world implementation. Stricter versions of these, cumulative brake derating and exponential collaborative braking, are also evaluated. Both can degrade capacity to near current roadway levels, especially if a large degree of amelioration is required. Increasing maximum acceptable collision speed, such as through designing vehicles to better withstand rear-end collisions, shows more promise in enabling safe intraplatoon interactions, especially for scenarios with small communication delays (i.e. under 50 ms).

Travelers experience different transportation-related problems on roadways ranging from congestion, delay, and crashes, which are partially due to growing background traffic and traffic generated by new developments. With regards to congestion, metropolitan planning organizations (MPOs) pursue a variety of plans for mitigating congestion. These plans include, amongst other measures, imposing impact fees. The current research evaluates how delay and safety can be incorporated in the mitigation process as special impact fees. This study also evaluates traffic projection methodologies used in traffic impact studies. Traffic volume is a critical factor in determining both current and future desired and undesired highway operations. Highway crashes are also influenced by traffic volume, as a higher frequency of crashes is expected at more congested locations and vice versa. Accurately forecasted traffic data is required for accurate future planning, traffic operations, safety evaluation, and countermeasures. Adhering to the importance of accurate traffic projection, this study introduces a simplistic traffic projection methodology for small-scale projection utilizing three parameters logistic function as a forecasting tool. Three parameters logistic function produced more accurate future traffic prediction compared to other functions. When validation studies were performed, the coefficient of correlation was found to be above 90 percent in each location. The t-values for the three parameters were highly significant in the projection. The confidence intervals have been calculated at a 95 percent confidence level using the delta method to address the uncertainty and reliability factor in the projection using logistic function. A delay mitigation fee resulting from increases in travel time is also analyzed in this research. In regular traffic flow, posted speed limit is the base of measuring travel time within the segment of the road. The economic concept of congestion pricing is used to evaluate the impact of this travel time delay per unit trip. If the relationship between the increase in time and trip is known, then the developer can be charged for the costs of time delays for travelers by using that relationship. The congestion pricing approach determines the average and marginal effect of the travel time. With the known values of time, vehicle occupancy, and number of travel days per year, the extra cost per trip caused by additional trips is estimated. This cost becomes part of the mitigation fee that the developer incurs as a result of travel time delays for the travelers due to the development project. Using the Bureau of Public Road (BPR) travel time function and parameters found in 2000 HCM (Highway Capacity Manual), the average and marginal travel times were determined. The value of time was taken as $7.50 per hour after reviewing different publications, which relate it to minimum wage. The vehicle occupancy is assumed as 1.2 persons per vehicle. Other assumptions include 261 working days per year and 4 percent rate of return. The total delay impact fee will depend on the number of years needed for the development to have effect. Since the developer is charged a road impact fee due to constructions cost for the road improvement, the delay mitigation fee should be credited to the road impact fee to avoid double charging the developer. As an approach to incorporate safety into mitigation fees, the study developed a crash prediction model in which all factors significantly influencing crash occurrences are considered and modeled. Negative binomial (NB) is selected as the best crash modeling distribution among other generalized linear models. The developed safety component of the mitigation fee equation considers scenarios in which the proposed new development is expected to increase crash frequency. The mitigation fee equation is designed to incorporate some roadway features and traffic characteristics generated by the new development that influence crash occurrence. Crash reduction factors are introduced and incorporated in the safety mitigation fees equation. The difference between crash frequency before and after the development is multiplied by the crash cost then divided by the trips to obtain crash cost per trip. Crash cost is taken as $28,000/crash based on literature review. To avoid double charging the developer, either the road impact fee is applied as a credit to the delay mitigation fee or vice versa. In summary, this study achieved and contributed the following to researchers and practitioners: ... Developed logistic function as a simplified approach for traffic projection ... Developed crash model for crash prediction ... Developed safety mitigation fee equation utilizing the crash modeling ... Developed delay mitigation fee equation using congestion pricing approach

Even though the practical experience of using coarse unbound granular materials is extensive, detailed knowledge on the mechanical and hydraulic behavior is to a large extent lacking. Regarding influence of water on mechanical properties, this is even more pronounced. The main objective of this work was to investigate the influence of water on behavior and properties of coarse granular materials. The study comprises measurements of resilient properties, soil-water characteristic curve and influence of water content on dielectric properties measured by the use of time domain reflectometry (TDR). The work described herein comprised two test series in terms of materials: firstly, a series where the grading was changed and secondly, a series where the influence of increased contents of free mica was studied. To measure resilient response, triaxial testing, using sample size of 500 mm diameter and 1000 mm height, was performed mainly using constant confining pressures. Tests were performed at incrementally varying water contents up to almost full saturation. Dielectric response and matric suction of compacted specimens were measured in a steel box at varying water content. Results from the first series indicated that the influence of water content on resilient properties depends on the material grading. The coarsest grading, containing least fines, experienced only a small reduction when brought close to saturation. Specimens with an increased amount of fines and more even distribution responded with a substantial loss of resilient modulus upon increased water content. It also appeared as water content increased, the specimens became more dilative. From the second series, generally, resilient modulus decreased with increased mica content and furthermore, elevated water contents caused reduction in stiffness. However, in relative terms, the reduction in resilient modulus caused by water decreased with increased mica content. The soil-water characteristic curves are influenced by grading coefficient and mica content; retentive capacity increases with decreased grading coefficient and increases with increased amount of mica. Volumetric water content as a function of apparent relative permittivity was fitted using a third-degree polynomial. Although, determined relationships deviated from Topp's (1980) relationship. Detailed information on the work is given in five enclosed papers. / QC 20100705

Graduation date: 1953

Highway lane closures cause reductions in the traffic throughput which lead to premature queuing. To minimize user delays, contractors are required to keep highway lanes open during the peak traffic hours and work at nights. However, these limitations can reduce the quality of the work and extend project duration. Finding a right balance between the times that the lanes can be closed and the times they should be kept open can increase the efficiency of the contractors’ work. Over 100 hours of throughput data were collected in two phases from 2007 to 2010 from Southern Ontario highways. Using regression analysis, a generic and a highway specific model were developed predicting the mean throughput in approximately 50% of cases within one hundred vehicles per hour per lane of the actual mean. Also the Simplified Work Zone User Delay Analysis model, developed in Phase 1, was refined to investigate the resulting queues.

Highway lane closures cause reductions in the traffic throughput which lead to premature queuing. To minimize user delays, contractors are required to keep highway lanes open during the peak traffic hours and work at nights. However, these limitations can reduce the quality of the work and extend project duration. Finding a right balance between the times that the lanes can be closed and the times they should be kept open can increase the efficiency of the contractors’ work. Over 100 hours of throughput data were collected in two phases from 2007 to 2010 from Southern Ontario highways. Using regression analysis, a generic and a highway specific model were developed predicting the mean throughput in approximately 50% of cases within one hundred vehicles per hour per lane of the actual mean. Also the Simplified Work Zone User Delay Analysis model, developed in Phase 1, was refined to investigate the resulting queues.

Weathering steel is a high-strength, low-alloy steel which has been proven to provide a significantly higher corrosion resistance than regular carbon steel. This corrosion resistance is a product of the small amounts of alloying elements added to the steel, which enable it to form a protective oxide layer when exposed to the environment. The main advantage of its use in bridges is that, under normal conditions, it may be left unpainted, leading to significantly reduced maintenance and environmental costs. Weathering steel has been a material of choice for highway structures for almost half a century, and a very large number of structures have been constructed with it. Although its use has for the most part been successful, it has also become evident that, in circumstances where there is the presence of salt and sulphur oxides, its performance is deficient. In these situations the corrosion penetration rate is much higher than expected, and the oxide layer forms in thick layers. This presents an added risk, since these layers flake off and fall onto the roadway. The degree of corrosion on structures can be very different, even if the structural type, location, and climate are similar. Therefore the focus of the thesis is on the lifespan of weathering steel highway structures. Primarily this research is concerned with the effect of corrosion on the integrity of these structures, as well as ways of quantifying corrosion loss and protecting the structure from further corrosion. In order to determine the lifespan of weathering steel highway structures subject to different rates of corrosion, a probabilistic structural analysis program has been developed to assess the time-dependent reliability of the structure. This program used iterative Monte Carlo simulation and a series of statistical variables relating to the material, loading, and corrosion properties of the structure. A corrosion penetration equation is used to estimate thickness loss at a selected interval, and the structural properties of the bridge are modified accordingly. The ultimate limit states of shear, moment, and bearing, and the fatigue limit state of web breathing, are taken into account. Three types of structures are examined: simply-supported box and I-girder composite bridges, and a two-span box girder bridge. Based on the structural analysis of the corroding bridge structures presented herein, it can be seen that corrosion to the weathering steel girders can cause reduced service lives of the structures. I-girder bridges are shown to be more susceptible to corrosion than box girder bridges, with continuous box girder bridges showing the best performance. The amount of truck traffic does not affect the reliability of the bridge. The short-span and high strength steel bridges are more susceptible to corrosion loss, primarily because their girders have thinner sections. A two-lane bridge also has better performance than the wider bridges because the weight of the barriers and sidewalks is carried by fewer girders, so these girders are stockier. The web breathing limit state is less significant than the combined ultimate limit states. Lastly, and most importantly, inspection data from a highway bridge is used to demonstrate the benefit that can be derived from using field data to update the time-dependent reliability. The ultrasonic thickness gauge (UTG) is a common tool for thickness measurement of steel sections. When used to measure weathering steel, this instrument provides accurate data about the depth of corrosion pits, but not their lateral dimensions. The measurement does not include the corrosion layer on the opposite side of the plate from the one being measured; however, if the corrosion layer is on the measured face, a disproportionate increase in the measured thickness can be seen. In order to prevent or minimize corrosion loss, the steel is currently painted, a process with several environmental and financial disadvantages. Therefore, three novel protection methods have been assessed in a cyclic corrosion test: a zinc metallizing, an aluminum-zinc-indium alloy metallizing, and a zinc tape with a PVC topcoat. All these coatings are designed to act not just as barriers, but also as sacrificial anodes. The test was run for 212 24-hr cycles, over the course of which the all the coatings were proven effective at protecting the steel substrate, regardless of steel type and surface roughness and pretreatment. In conclusion, the threat to all types of weathering steel highway structures by contaminant-induced corrosion is significant, but inspection data permits a more accurate prediction of time-dependent reliability for a structure, and protective coatings are a promising method of slowing the advance of corrosion.

No description available.

Weathering steel is a high-strength, low-alloy steel which has been proven to provide a significantly higher corrosion resistance than regular carbon steel. This corrosion resistance is a product of the small amounts of alloying elements added to the steel, which enable it to form a protective oxide layer when exposed to the environment. The main advantage of its use in bridges is that, under normal conditions, it may be left unpainted, leading to significantly reduced maintenance and environmental costs. Weathering steel has been a material of choice for highway structures for almost half a century, and a very large number of structures have been constructed with it. Although its use has for the most part been successful, it has also become evident that, in circumstances where there is the presence of salt and sulphur oxides, its performance is deficient. In these situations the corrosion penetration rate is much higher than expected, and the oxide layer forms in thick layers. This presents an added risk, since these layers flake off and fall onto the roadway. The degree of corrosion on structures can be very different, even if the structural type, location, and climate are similar. Therefore the focus of the thesis is on the lifespan of weathering steel highway structures. Primarily this research is concerned with the effect of corrosion on the integrity of these structures, as well as ways of quantifying corrosion loss and protecting the structure from further corrosion. In order to determine the lifespan of weathering steel highway structures subject to different rates of corrosion, a probabilistic structural analysis program has been developed to assess the time-dependent reliability of the structure. This program used iterative Monte Carlo simulation and a series of statistical variables relating to the material, loading, and corrosion properties of the structure. A corrosion penetration equation is used to estimate thickness loss at a selected interval, and the structural properties of the bridge are modified accordingly. The ultimate limit states of shear, moment, and bearing, and the fatigue limit state of web breathing, are taken into account. Three types of structures are examined: simply-supported box and I-girder composite bridges, and a two-span box girder bridge. Based on the structural analysis of the corroding bridge structures presented herein, it can be seen that corrosion to the weathering steel girders can cause reduced service lives of the structures. I-girder bridges are shown to be more susceptible to corrosion than box girder bridges, with continuous box girder bridges showing the best performance. The amount of truck traffic does not affect the reliability of the bridge. The short-span and high strength steel bridges are more susceptible to corrosion loss, primarily because their girders have thinner sections. A two-lane bridge also has better performance than the wider bridges because the weight of the barriers and sidewalks is carried by fewer girders, so these girders are stockier. The web breathing limit state is less significant than the combined ultimate limit states. Lastly, and most importantly, inspection data from a highway bridge is used to demonstrate the benefit that can be derived from using field data to update the time-dependent reliability. The ultrasonic thickness gauge (UTG) is a common tool for thickness measurement of steel sections. When used to measure weathering steel, this instrument provides accurate data about the depth of corrosion pits, but not their lateral dimensions. The measurement does not include the corrosion layer on the opposite side of the plate from the one being measured; however, if the corrosion layer is on the measured face, a disproportionate increase in the measured thickness can be seen. In order to prevent or minimize corrosion loss, the steel is currently painted, a process with several environmental and financial disadvantages. Therefore, three novel protection methods have been assessed in a cyclic corrosion test: a zinc metallizing, an aluminum-zinc-indium alloy metallizing, and a zinc tape with a PVC topcoat. All these coatings are designed to act not just as barriers, but also as sacrificial anodes. The test was run for 212 24-hr cycles, over the course of which the all the coatings were proven effective at protecting the steel substrate, regardless of steel type and surface roughness and pretreatment. In conclusion, the threat to all types of weathering steel highway structures by contaminant-induced corrosion is significant, but inspection data permits a more accurate prediction of time-dependent reliability for a structure, and protective coatings are a promising method of slowing the advance of corrosion.

Performance-based contracting (PBC) for roadway maintenance is relatively new among various alternative contracting options available at present and is increasingly drawing more attention from state Departments of Transportation (DOTs) and the contracting community. Because performance-based maintenance contracts extend over multiple years (typically 5-7 years) and shift performance risk to contractors, it is critical that contractors be selected based on a form of best-value method rather than on the conventional low-bid method. Currently, highway agencies use various methods for determining the best-value bid based on cost and technical scores. Five best-value bid identification methods that are already in practice by the state transportation agencies in Florida, Virginia, North Carolina, United Kingdom, and New Zealand were used as case studies for this research. These five methods were evaluated in terms of the agency’s willingness to pay for quality and the neutrality of these methods with respect to lowest bid and highest quality. To understand and describe the bid evaluation method, the agency can develop a willingness to pay (WTP) curve. This curve should represent the agency’s needs and budget, reflect their project characteristics, and accommodate associated performance risks. An Excel macro based software tool has been developed that automates these five best-value bid identification methods and also helps customize anyone of these options for any agency.