Oklahoma Department of Transportation

Microbiomes play a key role in the health of animal hosts. To improve conservation translocation programs like headstarting, it is necessary to consider how the structure of these programs impact the host-associated microbiome. Bringing animals into captivity introduces novel diets and environments; however, the extent to which these factors contribute to the structure of the host’s gut microbiome remains poorly understood. Additionally, it is unclear if periods of captivity leave a lasting signature on the host-associated gut microbiome, which could impact individual health and fitness in the long-term. In this study, we repeatedly sampled the gut microbiome of a cohort of headstart Texas horned lizards (Phrynosoma cornutum) throughout their transition from captivity to the wild. We also collected samples of extrinsic microbial communities present in their captive and wild diet and environment. Finally, we sampled the gut microbiome of wild resident lizards to serve as a baseline comparison. Using 16S rRNA microbial inventories, we examined differences in microbial community composition and diversity between pre-release headstart, post-release headstart, and resident lizards of the wild population. Additionally, we assessed the contribution of environmental and dietary microbial communities to the assembly of P. cornutum gut microbiomes in captivity and the wild. Our results suggest captive P. cornutum harbor gut microbiomes that are distinct from their wild counterparts. However, within two-months post-release, the headstart gut microbiome restructures to be indistinguishable from the wild resident microbiome. Microbiomes associated with the captive diet and environment are distinct in beta diversity, but not alpha diversity, from those in the wild. Our results provide important insights into host-associated microbiome dynamics associated with transition from captivity to the wild and can be used to inform conservation translocation practices.

Safe and efficient transportation of freight is important to the U.S. economy and economic growth. Between 1975 and 1997 domestic intercity tons of the U.S. freight grew 60%, and that growth in freight movement was placing pressure on a congested highway system. Between 1980 and 2002, truck travel grew by 90% while lane miles grew only 5%. The percentage of urban interstates carrying 10,000 or more trucks was 27% in 1998, and forecasted to grow to 69% in 2020. Freight volumes were also expected to increase by 70% by 2020. In 2015, the U.S. Congress responded to the persistent and growing voice of freight stakeholders and made freight mobility a national issue in the Fixing America’s Surface Transportation (FAST) Act. Each state is a key player to the implementation of freight mobility in the FAST Act. Oklahoma has a relatively large highway system mileage compared to its population, ranked 19th in state-owned system size. Located in the Crossroads of the U.S., Oklahoma is served by major highway corridors like Interstate 35, Interstate 40, and Interstate 44. The Oklahoma Department of Transportation (ODOT) is charged with planning, constructing, and maintaining Oklahoma’s surface transportation infrastructure, including the interstate system, the U.S. highway system, and the Oklahoma highway system. ODOT began the process of developing a FAST Act compliant state freight plan in 2016. A Freight Advisory Committee (FAC) was created to assist in the planning process by helping to prioritize goals and identify concerns around particular operational issues such as bottlenecks. The Oklahoma Freight Transportation Plan (OFTP) was approved on December 4, 2017. This paper provides a critical overview of the OFTP relative to the conditions of Oklahoma’s transportation infrastructure, particularly bridges and pavements. This plan sets forth a vision and goals, strategies and policies to achieve the goals, measures to track achievement, and investments selected because they support the goals. Importantly, ODOT has gone beyond planning for utilizing $100.2 million in National Highway Freight Program (NHFP) funds toward freight projects as required by the FAST Act. It has identified a series of investments for priority multimodal freight projects to be funded by traditional means, and all told has created an $875 million statewide freight investment program for the next five years.

Based on the thermodynamic theories and current experiment method of solid surface energy, surface energy of limestone aggregate in millimeter scale is determined by SGA -100 water vapor sorption analyzer. The major variation exhibited by limestone aggregates are Lewis base component, which is several times to that of mineral particles. Large sizes of the constituent particles forming millimeter size aggregates induce large surface energy. It is also shown that hydrophilicity of limestone aggregates vary severely, which means variety interfacial interaction between different particles.

Abstract Use of polymer-modified binder has become much more important in recent years to enhance the durability and strength of asphalt concrete (AC) pavements in order to sustain higher traffic volumes, heavier loads, and extreme weather conditions. Unlike neat (unmodified) asphalt binders, polymer-modified binders are sensitive to the applied stress levels and show a nonlinear response in rutting factor and phase angle. The widely used dynamic shear rheometer (DSR) test (AASHTO T315) is not sufficient to capture viscoelastic properties of polymer modified-asphalt binders. Thus, state transportation agencies often need to conduct additional expensive and time consuming “PG Plus” tests (e.g., elastic recovery (ER), force ductility, toughness, and tenacity) for characterizing polymer-modified binders. Multiple stress creep recovery (MSCR), a recently introduced test method (AASHTO TP 70) for measuring high temperature properties of an asphalt binder, is expected to replace the existing AASHTO T315 for short-term aged binder. In the current study, MSCR and Superpave tests were conducted on three commonly used performance grade (PG) binders (PG 64-22, PG 70-28, and PG 76-28) from 12 different sources throughout Oklahoma. Based on expected traffic loads and service temperatures, the tested binder samples were graded in accordance with the MSCR grading system. The non-recoverable creep compliance (Jnr) and MSCR % recovery values obtained from the MSCR tests were then analyzed using the polymer curve and quadrant methods to assess the feasibility of the adoption of the MSCR test method for conditions prevailing in Oklahoma. Findings of this study reveal that the MSCR test method can be used to characterize polymer-modified binders without penalizing suppliers or risking the users.

As part of ITS initiatives worldwide, Advanced Traveler Information Systems (ATIS) provide potential travelers with information and images from roadway and roadside technology. This information benefits the traveling public by improving pre-travel routing and other trip planning capabilities. As part of broader traffic management ITS strategies, these systems improve overall safety by reducing the number of congestion-related crashes and improve the efficiency of transportation systems by increasing roadway capacity. However, the development of an ATIS offers numerous challenges that are unique to the individual region served. The cost of deployment and operation is of critical importance, particularly for states with smaller populations and transportation budgets. This paper presents the design of the Oklahoma Pathfinder ATIS, addressing the state's constraints and exploiting the state's unique ITS deployment. It details the information capabilities, deployment experiences, and traveler reception of the system.

Usage of recycled asphalt pavement (RAP) in the construction of new pavements has increased in recent years due to the movement to conserve energy and raw materials, and reuse waste materials. To assess the effectiveness of RAP materials in new asphalt mixes, it is important to evaluate the properties of the recovered binders and aggregates. The widely used “Abson” method is employed in this study to recover asphalt binder from RAP. Also, the frequently used “NCAT ignition” method is used to extract aggregates. A laboratory study comprising two field RAP materials, two simulated RAP materials, and corresponding virgin materials was undertaken to assess possible influences of the aforementioned recovery processes. The performance grade (PG) of the recovered binders, and gradation, durability (LA Abrasion and Micro-Deval), specific gravity, sand equivalent, and insoluble residue of the extracted aggregates were evaluated as per the AASHTO and Oklahoma Dept. of Transportation (ODOT) standards. The test results showed that the Abson method notably influenced the critical PG temperatures of the recovered binder. It was also observed that some mechanical properties (durability and sand equivalent) of RAP aggregates were inconsistent with their virgin counterparts. Furthermore, field RAP aggregates showed significant variations in LA Abrasion loss and insoluble residue test results. The findings of this study are expected to be helpful in the evaluation of RAP for reuse in asphalt paving.

Environmental conditions such as temperature and moisture can significantly influence the performance of a pavement structure. These conditions vary within the pavement layers, degrading or enhancing the properties of pavement materials. The AASHTO 1993 design guide accounts for this influence by incorporating a single resilient modulus ( MR) value that represents the effective roadbed resilient modulus; the revised AASHTO Mechanistic–Empirical Pavement Design Guide (MEPDG) uses models that predict changes in modulus due to moisture, temperature, or both. The effect of changes in postcompaction moisture content (i.e., wetting or drying) on the resilient moduli of subgrade soils is evaluated. The effects of wetting and drying were examined by conducting resilient modulus tests on specimens compacted at various initial moisture contents: optimum moisture content (OMC), 4% drier than OMC (OMC – 4%), and 4% wetter than OMC (OMC + 4%). Results showed that MR–moisture content ( MRMC) relationships caused by drying exhibited higher values than the corresponding MRMC curves for specimens subject to wetting. The most significant finding was that changes in MR values depended on the initial compaction moisture contents; the MR values compacted at OMC exhibited a different drying and wetting trend than the ones compacted at OMC ± 4%. Finally, the MEPDG MR–moisture model was modified in this study to better predict the variations of resilient modulus with moisture changes.

Several models exist to predict the interaction between unsaturated soils and slab foundations or pavements. Validation of these models requires real-world data about the distribution and movement of water within the soil. Electrical resistivity tomography (ERT) offers an economical, non-destructive, and relatively non-invasive method of creating 2- and 3-dimensional views of moisture distribution. This is a case study of an asphalt bicycling/walking path constructed on an expansive clay subgrade. A test section was underlain by a horizontal moisture barrier, in an attempt to minimize seasonal shrink/swell behavior. A string of electrodes was installed across the pavement section, beneath the barrier. By measuring the subgrade resistivity at monthly intervals, it was believed possible to estimate the depth of the active zone, the edge moisture variation distance, the long-term equilibrium moisture beneath the covered area, and seasonal fluctuations of moisture at the edge.

In recent years, interest in determining the influence of moisture changes on the resilient modulus ( MR) of subgrade soils beneath a pavement has increased. This is because the 1993 AASHTO Guide for Design of Pavement Structures recommends using a single MR value. The design MR is expected to account for the seasonal variation in subgrade moisture content. This study was undertaken to evaluate the variation of MR with postcompaction moisture content and suction of selected subgrade soils in Oklahoma. A sandy soil (S-Soil) and a clayey soil (C-Soil) were used for laboratory testing. The C-Soil specimens to be subjected to wetting were prepared by a modified compaction method. The proposed method was expected to enhance the flow of water in a specimen during the wetting process. New laboratory procedures for wetting and drying of specimens were also introduced and were used to establish correlations among MR, moisture variation, and suction. Results indicate that MR-moisture content relationships for C-Soil exhibit a hysteretic behavior due to wetting and drying. A similar behavior was observed for S-Soil. The C-Soil was more susceptible than the S-Soil to moisture variation, as expected. It was also observed that changes in MR values and suction were influenced by the initial (compaction) moisture content.