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Evaluation of traffic control devices : year 3

Description: 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.
Date: March 2012
Creator: Carlson, Paul J.; Pike, Adam M.; Miles, Jeff D.; Ullman, Brooke R. & Borchardt, Darrel W.

Exploratory study : vehicle mileage fees in Texas

Description: 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.
Date: January 2011
Creator: Baker, Richard & Goodin, Ginger

Field and laboratory investigations for Full Depth Reclamation projects

Description: 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.
Date: March 2011
Creator: Sebesta, Stephen; Scullion, Thomas & Estakhri, Cindy K.

Field evaluation of asphalt mixture skid resistance and its relationship to aggregate characteristics

Description: 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.
Date: December 2010
Creator: Masad, Eyad; Rezaei, Arash; Chowdhury, Arif & Freeman, Thomas J.

Full-depth reclamation : new test procedures and recommended updates to specifications

Description: 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.
Date: July 2012
Creator: Scullion, Thomas; Sebesta, Stephen; Estakhri, Cindy K.; Harris, Pat; Shon, Chang-Seon; Harvey, Omar et al.

Highway safety design workshops

Description: 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.
Date: November 2010
Creator: Bonneson, James A. & Pratt, Michael P.

Identification of priority rail projects for Texas: initial methodology/user manual and guidebook

Description: "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."
Date: February 2012
Creator: Morgan, Curtis Alan

Implementation of Transverse Variable Asphalt Rate seal coat practices in Texas

Description: 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.
Date: January 2011
Creator: Krugler, Paul E. & Estakhri, Cindy K.

Improving stop line detection using video imaging detectors

Description: "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."
Date: August 2009
Creator: Middleton, Daniel R.; Longmire, Ryan; Charar, Hassan; Bullock, Darcy & Bonneson, James A.

Internal trip capture estimator for mixed-use developments

Description: 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.
Date: February 2010
Creator: Bochner, Brian S. & Sperry, Benjamin R.

Laboratory and field performance measurements to support the implementation of warm mix asphalt in Texas

Description: 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.
Date: July 2012
Creator: Estakhri, Cindy K.

Landside freight access to airports : findings and case studies

Description: "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."
Date: August 2010
Creator: Frawley, William E.; Borowiec, Jefferey D.; Protopapa, Annie A.; Morgan, Curtis Alan & Warner, Jeffery E.

Manual for Assessing Safety Hardware test 3-10 on 31-inch W-beam guardrail with standard offset blocks

Description: "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."
Date: November 2010
Creator: Abu-Odeh, Akram Y.; Menges, Wanda L. & Bligh, Roger P.

Manual for Assessing Safety Hardware test 3-11 of the Texas Department of Transportation Portable Concrete Traffic Barriers with sign support assembly

Description: 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.
Date: January 2011
Creator: Williams, William F. & Menges, Wanda L.

Manual for Assessing Safety Hardware test 3-11 on the Texas T101 bridge rail

Description: 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.
Date: March 2011
Creator: Bligh, Roger P. & Menges, Wanda L.

MASH test 3-37 of the TxDOT 31-inch w-beam downstream anchor terminal

Description: Report discussing the findings of a study into issues related to roadside safety devices: "The objective of this study was to develop a suitable replacement for the downstream 'turn-down' guardrail anchor system. The 'turn-down' guardrail anchor system does not meet mandated test requirements under MASH for upstream anchor application terminals; however, it does meet downstream requirements for previous crash testing standard" (abstract). It includes background information, system details, test requirements and evaluation criteria, crash test procedures, crash test results, and conclusions.
Date: October 2011
Creator: Bligh, Roger P.; Menges, Wanda L. & Arrington, Dusty R.

Microsurfacing in Texas

Description: This report describes the current state of practice of microsurfacing in Texas and compares it to best practices extracted from existing literature. A survey of DOT personnel, contractors and emulsion suppliers in Texas provides insight into the most crucial factors contributing to the success or failure of a microsurfacing. From the results of the survey, literature reviews, case studies and site visits, the research team analyzed material selection and mix design methods, construction practices, equipment practices and performance measures for microsurfacings.
Date: August 2011
Creator: Broughton, Benjamin & Lee, Soon-Jae

Mobility and economic effects of system investments in Texas: 2010 to 2020

Description: "The report summarizes estimates of the consequences of current funding levels and a range of greater and lesser funding amounts. The report describes the population, travel, system extent and expenditure data and analyses used to develop the mobility and economic effect analyses. An associated study by the Center for Transportation Research analyzed pavement maintenance spending and condition. Both the mobility and pavement studies were used as part of the March 2011 Texas 2030 Committee report."
Date: August 2011
Creator: Lomaz, Tim