"In this report the research project resulted in a statewide map recommending primary and alternate Oversize/ overweight (OS/OW)route networks for the most common origins and destinations based on historical Motor Carrier Division data. Keeping strategic routes open for OS/OW loads and minimizing the number of reroutes along the way will reduce the impedance and unknowns in this critical segment of the motor carrier industry."
The Texas Department of Transportation (TxDOT) has a comprehensive on-going travel survey program that supports the travel demand models being developed for transportation planning efforts in urban areas throughout Texas. One component of the survey program is the external travel survey. External travel surveys provide data on travel movements into, out of, and through urban areas. In recent years, there has been a heightened sensitivity to the methods used to collect external survey data as well as the type of data that is collected. This research examines alternative methods for collecting data on external travel movements and evaluates the potential for synthesizing/modeling external travel in lieu of conducting external surveys. The research will provide recommendations to TxDOT on the most viable methods to estimate external travel movements for use in travel demand models in urban areas in Texas.
"This report summarizes the concerns expressed with the current Texas Department of Transportation(TxDOT) methods, presents approaches some TxDOT districts have taken to overcome problems, and summarizes the current status of other agencies' efforts at mechanistic based acceptance for flexible base. Also this report presents results and findings from a full-scale compaction experiment."
"In 2009, the Texas Transportation Institute produced for the Texas Department of Transportation a document called Video over IP Design Guidebook. This report summarized an implementation of that project in the form of a workshop. The workshop was developed and presented as a pilot in Austin in 2010 and taught an additional four times in 2011 in Fort Worth, Lubbock, Houston, and San Antonio."
Report regarding efforts to develop a benefit-cost analysis methodology for safety rest areas in Texas and to demonstrate its application in select corridors throughout the state. This project also considers approaches to developing rest areas that could reduce costs to the public.
"For this study, a total of 30 heavy-duty diesel vehicles (HDDVs) were selected from City of Houston (COH) fleet based on opacity testing for HEs and random selection for non-HEs. With the selected 30 vehicles, driving and idling emission testing were performed to characterize their emissions with respect to vehicle classes, types (HE or non-HE), and model years."
"An instrumented, simulated bridge pier was constructed, and two full-scale collisions with an 80,000-lb van-type tractor-trailer were performed on it. The trailer was ballasted with bags of sand on pallets. The simulated pier was 36 inches in diameter and was supported in the longitudinal direction by two load cells. Force-versus-time data were obtained from the load cells."
"This report aimed to conduct a comprehensive evaluation of compaction of asphalt pavements and develop software for monitoring field compaction in real time.The results were used to determine the effects of compaction temperature, compaction method, mixture design, and base type on the compactability of asphalt mixtures.Also in this report researchers developed a system for monitoring and documenting the compaction process of asphalt mixtures called compaction monitoring system (CMS)."
"This report summarizes the delivery and outcome of a series of workshops conducted at 23 Texas Department of Transportation (TxDOT) districts across the state on corridor management and preservation in Texas. The workshops served as follow-up implementation work for research project 0-5606, "Creating Partnerships with Local Communities to Manage and Preserve Corridors." The report provides an overview of the project and documents the dates, locations, and attendance of workshops implemented during the three-year project period."
"This two-year project was designed to provide TxDOT with comprehensive review and update of mounting details and standards for large and small sign supports, and to provide a mechanism for TxDOT to quickly and effectively evaluate and address high priority needs related to sign support systems."
The TxDOT Design Division is in the process of developing new guardrail standards that comply with the AASHTO Manual for Assessing Safety Hardware (MASH). The new guardrail system will provide increased capacity and improved impact performance relative to the current design. A key feature of the new system is an increased in rail mounting height from 27 inches to 31 inches. TxDOT's current TL-2 metal beam transition is 27 inches tall and is not compatible with the new 31 inch guardrail system. While the high-speed, nested thrie beam transition system meets MASH guidelines and is compatible with a 31-inch guardrail, it would be cost-prohibitive to use it on all roadways. The objective of this research was to develop a transition that is suitable for use on lower speed roadways, less expensive and complex than the current high-speed (i.e., TL-3) transition design, and is compatible with a 31-inch guardrail. A low-cost guardrail-to-bridge rail transition was successfully developed and tested under MASH Test Level 2 conditions. It is compatible with a 31-inch guardrail and can connect to rigid concrete bridge rails. It is considered suitable for implementation on roadways that have traffic conditions appropriate for the use of TL-2 safety hardware. Use of this system provides significant savings in material and installation cost compared to the high speed transition system.
"This report focused on the evaluation of traffic sign sheeting performance in terms of meeting the nighttime driver needs. Using the luminance requirements derived from the study and market-weighted headlamp flux matrices, the researchers developed an approach to sigh sheeting specification that is based on nighttime driver needs."
"This report presents data and technical analyses for Texas Department of Transportation Project 0-5235. This project focused on the evaluation of traffic sign sheeting performance in terms of meeting the nighttime driver needs. The goal was to develop a nighttime driver needs specification for traffic signs. Full information on the project is presented in Report 0-5235-1 Volume 1."
This research investigated the overhang and shear capacity of a precast overhang system for potential use during the construction of bridges with precast overhang panels. The research was performed in three phases: the Phase 1 research including work specifically for the Rock Creek Bridge in Parker County, Texas; the Phase 2 research for general precast overhang panels, and; the Phase 3 research investigating the shear capacity. Grout material characteristics were also assessed for possible use in the haunch; constructability issues were also addressed.
The objective of this project is to investigate field evaluation plans and procedures and develop field performance-based evaluation procedures for pavement marking materials (PMMs). Field decks are designed incorporating regular long lines, long line in the travel lane, and transverse lines for accelerated testing, while also considering different installation procedures. Three different test field deck sites are selected across the state considering area climate, roadway surface type, and traffic condition. Carefully selected PMM products are installed and monitored for their field performance over time. The relationships between transverse and longitudinal test decks are evaluated with correlation analysis. A tracking database is developed and can record and interactively query all relevant data, track individual jobs and products, and graphically display performance changes over time.
"This document summarized the research conducted and the conclusions reached during the development of guidelines for pedestrian safety treatments at signalized intersections. The guidelines are focused on treatments that alleviate conflicts between left-turning vehicles and pedestrians."
"The testing and analyses documented in this report (0-6100-3) provides a new equation for determining the number of shear pockets required for the various shear connector/coupler systems evaluated in this research. This equation was used to determine the number of shear pockets required for the newer TxDOT girders."
"In recent years, the Texas Department of Transportation has made significant progress with the development and implementation of new technologies to measure the uniformity of new hot mix asphalt layer construction. In Project 0-6992, researchers took this check one step further by developing an accurate global positioning system tracking system for compaction rolling so that the compaction effort applied can be monitored for 100 percent of the new surface. This report presents details of the hardware and software developed in this study. The system was field tested on a number of new overlay projects in Texas."
"This report summarizes the technical work performed developing and incorporating Metropolitan Planning Organization sub-models into the existing Texas Revenue Estimator and Needs Determination System (TRENDS) model. Additionally, this report explains the maintenance and monthly updates performed on the TRENDS model."
"This report documents the findings of the Texas Department of Transportation (TxDOT)sponsored research project that investigated the possible causes of the cracking and developed recommendations to prevent the occurrence of such cracking."
"This report describes the work completed to measure the impact of increased level of energy-related activities on the Texas Department of Transportation (TxDOT) right-of-way and infrastructure, as well as develop recommendations to reduce and manage TxDOT's exposure and risk resulting from those activities."
Changes in the population and land area of urbanized areas in Texas will play a significant role in determining the allocation of public transportation funds to service providers in Texas after Census 2010. The purpose of this research report is to review the impacts of the changes in urbanized area population and non-urbanized (rural) population and land area for 2010 on the current Texas Transit Funding Formula for allocation of Federal Section 5311 and state rural and urban funds. This collaborative effort between the Texas Transportation Institute and the Institute for Demographic and Socioeconomic Research at the University of Texas at San Antonio draws upon the complementary expertise of public Transportation planners, demographers, and geographic information systems professionals of the two research organizations. The research project identifies areas with the potential to exceed 200,000 in population and those non-urbanized areas that have potential to become urbanized (over 50,000 people) in 2010. The implications of these changes will be examined relative to the current public transportation funding allocations. The research staff provides a comprehensive assessment of these changes for the state as a whole and for individual transit service providers.
"The objectives of this project were to (a) provide a review of technical design and engineering requirements for utility accommodation in Texas, (b) provide an assessment of potential impact of overweight loads on buried utilities, (c) provide recommendations for a business process for TxDOT overweight routing coordination, (d) provide recommendations for changes to TxDOT manuals, (e) provide an assessment of UAR adequacy to deal with overweight loads on buried utilities, and (f) provide recommendations for changes to the UAR."
This report focuses on the year one project objectives, which were (a) provide a review of technical design and engineering requirements for utility accommodation in Texas, (b) provide a preliminary assessment of potential impact of overweight loads on buried utilities, (c) provide a preliminary assessment of Utility Accommodation Rules (UAR) adequacy to deal with overweight loads on buried utilities, (d) provide preliminary recommendations for a business process for Texas Department of Transportation overweight routing coordination, and (e) provide recommendations for the phase 2 utility damage evaluation.
This project was established to provide a means of conducting small-scale research activities on an as-needed basis so that the results could be available within months of starting the specific research. This report summarizes the research activities that were conducted between September 2010 and August 2011. There were five primary activities and five secondary activities. The five primary activities were evaluating nighttime visibility along rural highways with bright signs, continuing the evaluation of lead-free thermoplastic pavement markings, evaluating contrast pavement marking layouts, continuing the evaluation of accelerated pavement marking test decks, and providing district support for hurricane evacuation routing. In addition, the researchers also started to evaluated criteria for setting 80 mph and 85 mph speed limits, evaluated bridge clearance signing, narrowed the focus of a rotational sign sheeting study, provided technical support for the Texas Manual on Uniform Traffic Control Devices (MUTCD), and provided technical support for the Texas Department of Transportation (TxDOT) sign sheeting specification.
This project evaluates Vehicle Mileage (VM) fees as a possible funding mechanism for meeting the State of Texas' long-term transportation needs. Researchers conducted listening sessions with the general public and stakeholders to gather input on the concept. Researchers also prepared a decision matrix that can aid policy makers in evaluating the various trade-offs in policy that will be encountered in vehicle mileage fee system development. This study identified both challenges and opportunities for implementation of VM fees.
Full-depth reclamation (FDR) offers a timely, cost-effective solution to restore a pavement's condition. However, FDR represents only one technique in the engineer's toolkit available for addressing deteriorating pavement conditions. The purpose of this project is to provide guidance on determining whether a pavement is a candidate for FDR and, if so, what design, construction, and inspection processes will maximize the performance of the completed reclamation. This report presents initial recommendations for selecting a candidate FDR project and developing design options (including field sampling and lab design protocols). Along with a literature review, these recommendations are illustrated by application on several projects in the Texas Department of Transportation's Austin and Dallas Districts.
This report documents the findings from the research that was carried out as part of Phase II of TxDOT Project 0-5627. The research included measurements and analysis of mechanical and physical properties of aggregates used in surface mixes in the state of Texas. These properties were aggregate shape characteristics measured using the Aggregate Imaging System (AIMS), British Pendulum value, coarse aggregate acid insolubility, Los Angeles weight loss, Micro-Deval weight loss, and Magnesium sulfate weight loss. In addition, a database of field skid number measurements that were collected over a number of years using the skid trailer was developed. The Dynamic Friction Tester (DFT) and Circular Texture Meter (CTMeter) were used to measure friction and texture, respectively, of selected asphalt pavement sections. These data and measurements were used to carry out comprehensive statistical analyses of the influence of aggregate properties and mixture design on skid resistance value and its variability. Consequently, a method and software were developed for predicting asphalt pavement skid resistance. This method requires inputs that describe aggregate resistance to polishing, mixture gradation, and traffic. The developed software can be used to select the mixture type and aggregate source that are needed to achieve the required level of skid resistance for a given service life.
Rehabilitating an old pavement by pulverizing and stabilizing the existing pavement is a process referred to as Full Depth Reclamation (FDR). The stabilized layer becomes either the base or sub-base of the new pavement structure. This process has been used widely for over 20 years in Texas to strengthen and widen structurally inadequate pavement sections. This project developed guidelines on successful FDR practices, developed training materials, and identified areas where improvements to current practices are required. To improve the FDR process, this report includes the following enhancements: (1) As current laboratory testing to select the optimal type and amount of stabilizer takes too long and requires too much material, continue to run parallel testing with the small sample test protocols proposed in this report; (2) Use the falling weight deflectometer (FWD) during construction to validate that the design assumptions are being met; (3) Implement the proposed bond test to select the optimum prime material and amount needed to effectively bond the base to the surfacing materials; (4) Modify the specifications to avoid working in freezing conditions; and (5) Consider implementing the other modifications to specifications proposed in this report.
Highway safety is an ongoing concern for the Texas Department of Transportation (TxDOT). As part of its proactive commitment to improving highway safety, TxDOT is moving toward including quantitative safety analyses earlier in the project development process. To assist in achieving this goal, TxDOT research project 0-4703 developed the Roadway Safety Design Workbook for engineers responsible for highway geometric design. This Workbook describes quantitative safety relationships for specific design components known to be correlated with crash frequency. As part of TxDOT Project 0-4703, a series of workshops were developed to share safety information with TxDOT roadway designers. Information in the Workbook was used as the basis for the workshops. The workshops addressed rural highways, urban streets, and freeways. They included a mixture of classroom discussion and hands-on training activities for the participants. The participants indicated that the information presented in the workshops will be beneficial as they make decisions about highway safety improvements.
"This project developed a system of evaluative tools for the Texas Department of Transportation (TxDOT) to prioritize its investments in rail-related projects on a statewide basis. This work is meant to ensure that the limited available funding for rail projects is applied in the most beneficial and efficient manner and is focused upon addressing TxDOT's strategic goals. From the findings, researches recommend a transparent methodology for evaluating proposed rail projects and establishing an initial process through which rail-related investments can periodically be re-evaluated."
An implementation project was performed to expand use of transversely varied asphalt rate (TVAR) seal coat practices in all districts. The project included nine regional workshops, continued field texture testing of test sites, provided one set of sand patch test equipment to each Texas Department of Transportation (TxDOT) district, and published 500 copies of the TVAR Field Guide for broad TxDOT distribution.
"The Texas Department of Transportation and other state departments of transportation as well as cities nationwide are using video detection successfully at signalized intersections. However, operational issues with video imaging vehicle detection systems (VIVDS) products occur at some locations. The resulting issues vary but have included: camera contrast loss resulting in max-recall operation, failure to detect vehicles leading to excessive delay and red-light violations, and degraded detection accuracy during nighttime hours. This research resulted in the development of a formalized VIVDS test protocol and a set of performance measures that agencies can incorporate in future purchase orders and use to uniformly evaluate VIVDS products. It also resulted in the development of a VIVDS video library and conceptual plans for a field laboratory for future projects to deploy a range of VIVDS products at an operational signalized intersection. Researchers evaluated alternative VIVDS stop line detection designs and developed methods for enhancing the operation of VIVDS through adjustments in controller settings for day versus night versus transition periods, zone placement, and camera placement."
This report describes a spreadsheet tool for estimating trip generation for mixed-use developments, accounting for internal trip capture. Internal trip capture is the portion of trips generated by a mixed-use development that both begin and end within the development. The importance of internal trip capture is that those trips satisfy a portion of the total development's trip generation and they do so without using the external road system. As a result, a mixed-use development that generates a given number of total trips creates less demand on the external road system than single-use developments generating the same number of trips. This report describes the spreadsheet estimator and how to use it. It describes the data behind the estimator as well as how those data are applied. The two Texas mixed-use developments from which most of the data were derived are also described. This report is supplemented by the Excel® spreadsheet itself as well as task memoranda that document the survey data collected as part of this project.
An objective of this study was to monitor the performance of more than 10 warm mix asphalt (WMA) projects in the state. Several WMA technologies were included in the study (foaming, Advera, Evotherm, Rediset, Sasobit) and it was determined that performance of the warm mix was comparable to hot mix. In addition, mix from two warm mix projects were subjected to different curing times and temperatures and then evaluated for mixture volumetrics and performance properties. Results from this study lend support to the current procedures the Texas Department of Transportation has adopted.
"Texas' airports play a large role in the national and regional movement of goods by air. This includes goods moved within the state, across the country, and internationally to several continents. Most of this movement of goods is accomplished at the largest airports in Texas. However, as freight demand grows, a time will come when other airports will need to be utilized to accommodate additional demand. Properly planned transportation infrastructure is critical to ensure the vitality of an airport's freight operations. Time-sensitive air freight requires high levels of operational efficiency, which is generally optimized by taking steps to ensure both freight and passenger roadway access within the airport boundaries. Connections and design features of regional highways near the airports are no less important because they allow access to these important economic generators. This research report identifies the issues, barriers, physical bottlenecks (e.g., infrastructure needs), and solutions (including funding mechanisms) concerning landside access to airports in Texas. Inner city airports in large metropolitan areas sometimes face roadway geometric challenges, but typically have relatively low cargo activity levels. Shipping representatives stated that wayfinding is a key characteristic in providing good landside freight access to airports. Signage needs to be visible and informative in advance of necessary turns or lane changes. Efforts need to be taken to minimize comingling of freight and passenger traffic in areas near the passenger terminals. A variety of funding opportunities exist through public, private, and shared sources to improve access to airports."
"The test reported herein corresponds to American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) test 3-10. This is primarily a severity test that assesses risk of injury to the vehicle occupants."
This report presents the details of the design developed for mounting the traffic control sign support on top a portable concrete traffic barrier (PCTB), description of the full scale crash test performed on the design, and an assessment and evaluation of the performance of the PCTB with the sign support mounted on top according to specifications of "Manual for Assessing Safety Hardware" (MASH). The PCTB mounted sign support assembly anchored to the top of the TxDOT Type 2 PCTB tested for this project performed acceptably for MASH test 3-11.
The Texas T101 bridge rail is widely used in the state of Texas. Previous testing demonstrated its ability to contain and redirect passenger cars and a 20,000-lb school bus. Based on this testing, the Federal Highway Administration accepted the T101 bridge rail as an NCHRP Report 350 TL-3 barrier. However, its impact performance with pickup trucks was never evaluated. Under research project 0-5526, Impact Performance of Roadside Safety Appurtenances, researchers conducted a performance assessment of Texas roadside safety devices to help evaluate the impact of adopting the new AASHTO Manual for Assessing Safety Hardware (MASH) guidelines on current hardware. Testing and evaluation of the T101 bridge rail was recommended as a high priority. This recommendation was based primarily on the absence of pickup truck testing on the system, and concerns that the 27-inch rail height may not be compatible with pickup trucks and SUVs under design impact conditions. The T101 bridge rail did not meet MASH evaluation criteria for test 3-11. The vehicle overturned after losing contact with the barrier.
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