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Development of a MASH TL-2 guardrail-to-bridge rail transition compatible with 31-inch guardrail

Description: 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.
Date: December 2011
Creator: Bligh, Roger P.; Arrington, Dusty R. & Menges, Wanda L.
Item Type: Report

TxDOT uses of real-time commercial traffic data : opportunity matrix

Description: Based on a TxDOT survey, a review of other state DOTs, and researcher understanding of Intelligent Transportation System (ITS) needs, the Texas Transportation Institute (TTI) team developed a comprehensive list of opportunities for TxDOT to consider pertaining to future use of private sector (PS) data. Specific opportunities for applying private data were reviewed in light of accuracy of the data, coverage areas, data availability, cost, and control of the data stream.
Date: January 2012
Creator: Middleton, Dan; Brydia, Robert; Kraus, Edgar; Cheu, Kelvin; Rajbhandari, Rajat, 1973-; Songchitruksa, Praprut et al.
Item Type: Report

Benefits of public roadside safety rest areas in Texas : technical report

Description: 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.
Date: May 2011
Creator: Carson, Jodi L.; Pezoldt, Val J.; Koncz, Nicholas A., 1964- & Obeng-Boampong, Kwaku Oduro, 1977-
Item Type: Report

Development of a MASH TL-3 median barrier gate

Description: Report regarding a median barrier gate designed to both offer protection to motorists and easier cross-median access for emergency and maintenance vehicles.
Date: February 2011
Creator: Bligh, Roger P.; Arrington, Dusty R.; Sheikh, Nauman Mansoor; Silvestri, Chiara & Menges, Wanda L.
Item Type: Report

Energy developments and the transportation infrastructure in Texas

Description: "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."
Date: March 2012
Creator: Quiroga, César A.; Fernando, E. G. & Oh, Jeongho
Item Type: Report

Modern traffic control devices to improve safety at rural intersections

Description: "The goal of this project was to obtain a better understanding of modern TCD capabilities. Researchers conducted the following tasks literature review, crash data examination, TxDOT district survey, laboratory survey, field study, and development of principles for selecting TCDs."
Date: September 2011
Creator: Fitzpatrick, Kay; Chrysler, Susan T.; Sunkari, Srivivasa R.; Cooper, Joel; Park, Byung-Jung & Higgins, Laura
Item Type: Report

Studies to determine the effectiveness of automated flagger assistance devices and school crossing devices

Description: "This report describes the methodology and results of analyses performed to determine motorist understanding, as well as the operational and safety effectiveness, of automated flaggers assistance devices (AFADs) relative to the use of flaggers at lane closures on two-lane, two-way roadways."
Date: October 2011
Creator: Finley, Melisa D.; Ullman, Brooke R.; Trout, Nada D. & Park, Eun Sug
Item Type: Report

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.
Item Type: Report

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.
Item Type: Report

Non-vital advance rail preemption of signalized intersections near highway-rail grade crossings

Description: The Texas Department of Transportation (TxDOT) primarily uses simultaneous preemption of traffic signals near highway-rail grade crossings to clear queued vehicles prior to the arrival of a train at the crossing. At some intersections, 20 seconds of advanced warning may not be sufficient to allow the traffic signal to clear pedestrians using the normal clearance intervals between phases. The research developed an alternative method (non-vital advance preemption) of ensuring adequate pedestrian clearance in the presence of an approaching train without interfering with the normal preemption sequence at the intersection or installing costly additional track circuitry needed to provide advance preemption. Two strategies were investigated to ensure pedestrian clearance time. The first utilizes a lower-level preemption sequence to guarantee full pedestrian clearance to a terminating phase before the traffic signal starts the preemption sequence. The second strategy uses the pedestrian-omit feature to prevent the controller from activating the pedestrian interval if there is not sufficient time in advance of the start of the preemption sequence to provide full pedestrian clearance.
Date: June 2007
Creator: Balke, Kevin N.; Engelbrecht, Roelof Johannes & Ruback, Leonard G.
Item Type: Report

Development guidance for sign design standards

Description: "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."
Date: November 2011
Creator: Silvestri, Chiara; Arrington, Dusty R.; Bligh, Roger P. & Menges, Wanda L.
Item Type: Report

Development of a model performance-based sign sheeting specification based on the evaluation of nighttime traffic signs using legibility and eye-tracker data

Description: "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."
Date: September 2010
Creator: Carlson, Paul J.; Miles, Jeffrey D.; Park, Eun Sug; Young, Sarah; Chrysler, Susan & Clark, Jerremy
Item Type: Report

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.
Item Type: Report

Performance comparison of various seal coat grades used in Texas

Description: This report documents research efforts to provide comparative quantitative performance information for various grades of seal coat aggregate available in the Texas Department of Transportation standard specifications. Length of service before replacement and level of noise generated at the tire-pavement interface were the primary focuses of the relative performance evaluations. The additional service life possible from seal coats with larger aggregate and higher asphalt application rates is compared to the additional cost generally associated with these larger aggregate seal coats. The comparative performance information combined with knowledge gathered from numerous department field engineers resulted in the development of guidelines for optimal seal coat grade selection.
Date: July 2012
Creator: Krugler, Paul E.; Wirth, John E.; Estakhri, Cindy K.; Freeman, Thomas J.; Wikander, John P. & Wimsatt, Andrew J.
Item Type: Report

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
Item Type: Report

School traffic workshop: dealing with Texas-sized problems around schools

Description: "This report summarized the series of "Traffic around Schools"" workshops conducted throughout the state of Texas to familiarize TxDOT employees and partner agencies with two key products from previous research projects (0-4286 and 0-5470) and other tools and guidance that are available for dealing with problems around schools."
Date: October 2011
Creator: Brewer, Marcus A.; Fitzpatrick, Kay & Cooner, Scott A.
Item Type: Report

Development of Texas Transportation Institute's asphalt compaction monitoring system

Description: "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."
Date: July 2012
Creator: Liu, Wenting; Scullion, Thomas & Kassem, Emad
Item Type: Report

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
Item Type: Report

The Freight Shuttle System : advancing commercial readiness

Description: This report summarizes the results of research aimed at advancing the commercial readiness of a new hybrid mode of inter-modal freight transportation called the Freight Shuttle System (FSS).
Date: November 2010
Creator: Roop, Stephen S.; Ragab, Ayman H.; Olson, Leslie E.; Protopapa, Annie A.; Yager, Michael A.; Morgan, Curtis Alan et al.
Item Type: Report