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Crash-based safety analysis is set back by several shortcomings such as randomness and rarity of crash occurrences, lack of timeliness, and inconsistency in crash reporting. Non-crash-based safety analysis has been around for more than three decades but its potential was limited due to a difficulty in the data collection and the evaluation. Recent advancement in digital videos and image detection technology renewed our interest in facilitating the data collection and improving the evaluation method. Two image detection systems for the measurement of traffic characteristics were evaluated: (a) a commercial video detection system and (b) proprietary image processing software. The measurement evaluation revealed that both systems were still not sufficiently accurate for the safety evaluation purpose and thus a manual measurement from digitized video clips was preferred for a collection of evaluation data. We proposed a novel application of extreme value theory to safety evaluation based on observable traffic characteristics. The proposed method was evaluated by applying to right-angle collisions at signalized intersections. A traffic characteristic so-called post-encroachment time (PET) was collected at selected intersections as a surrogate safety measure. Based on PET characteristics, risk and frequency of rightangle crashes at the studied intersection or individual conflict zone can be estimated using only the data collected at the location. For comparison, a traditional approach to safety analysis using Poisson and negative binomial regression analyses was also examined. Both evaluation methods – extreme value approach and regression – indicate a significant relationship between PETs and historical crash data. Simulation experiments were carried out to examine the effect of observation period on a variance of estimates obtained the proposed method. Advantages and problems with the proposed method are described in this study. A simple method for an evaluation of the

0-6583, 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.

Project 0-6121, Mass evacuations of the Texas Gulf Coast remain a difficult challenge. These events are massive in scale, highly complex, and entail an intricate, ever-changing conglomeration of technical and jurisdictional issues., This project focused primarily on the specific issue of developing a new technical tool to help TxDOT and, other key operating agencies/stakeholders better predict when major elements of evacuation operations, should be implemented. In particular, a variety of technical analyses were employed to develop a new, prototype decision support system that provides additional insights to more effectively decide when, evaculane shoulder operations versus full contraflow operations are needed to manage evacuation demand., This new tool has a predictive mechanism designed to provide lead time for implementing these two, prospective operational scenarios. The work conducted during this research involved a large-scale, application of the DynusT model, and integrates several different factors into the evacuation operation, decision-making process―namely real-time traffic conditions, hurricane characteristics (strength and size), a nd human behavior.

Project 0-6120, Exit gore signs present a significant maintenance challenge for TxDOT. There is concern regarding the safety, of personnel working in gore areas to replace these signs, and the resources necessary for continual, maintenance. The objective of this project was to identify and evaluate alternative methods that may reduce, the number of sign hits. Researchers visited several sites with safety problems related to frequent sign hits, determined factors that contribute to sign crashes, and recommended potential treatments. They also evaluated, the impact of eliminating exit gore signs at locations where appropriate advance warning with overhead exit, signs are provided. Field studies were conducted at two freeway exits in Corpus Christi, Texas. It was found, that the lack of exit gore signs at the two freeway exits did not have any negative consequences in terms of, vehicle speeds, deceleration behavior, and erratic maneuvers.

Project 0-6390, A primary product of this research was the Asset Management Guidebook that TxDOT division and district, personnel can use to help them define, develop, and implement asset management across all levels—, particularly as it relates to establishing performance measures for safety and operations. The guidebook is a, stand-alone product and contains easy-to-use, practical guidelines that TxDOT personnel can use to identify, the best approach to asset management on three possible levels if feasible and practical: (1) total asset, management for large urban areas encompassing multiple counties, (2) asset management of critical, functions on a smaller regional scale—such as maintenance of roadside components excluding the pavement, and (3) asset management for specific types of assets—such as pavement markings or light emitting diode, (LED) signal indications—that may be based on warranty specifications. The research team also, recommends that they present to TxDOT district engineers the results of the project to facilitate the, dissemination of this research and present the potential benefits of asset management for safety and, operations in the organization and the effective use of all of its resources.

Project 0-6121, Mass evacuations of the Texas Gulf Coast remain a difficult challenge. These events are massive in scale, highly complex, and entail an intricate, ever-changing conglomeration of technical and jurisdictional issues., This project focused primarily on the specific issue of developing a new technical tool to help TxDOT and, other key operating agencies/stakeholders better predict when major elements of evacuation operations, should be implemented. In particular, a variety of technical analyses were employed to develop a new, prototype decision support system that provides additional insights to more effectively decide when, evaculane shoulder operations versus full contraflow operations are needed to manage evacuation demand., This new tool has a predictive mechanism designed to provide lead time for implementing these two, prospective operational scenarios. The work conducted during this research involved a large-scale, application of the DynusT model, and integrates several different factors into the evacuation operation, decision-making process―namely real-time traffic conditions, hurricane characteristics (strength and size), and human behavior.

0-6659, 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.

Project 0-6828, Early indications from the use of the newest vehicle detectors for high-speed signalized intersections, suggested that they perform well as replacements for the Texas Department of Transportation’s, (TxDOT’s) legacy systems, but this early conclusion needed verification based on rigorous field testing, in a variety of traffic and environmental conditions. This research investigated the performance, characteristics of detectors designed for the stop line area and indecision zone detection. In some cases, new detectors involved two technologies to cover both upstream and stop line areas. Increasing use of, infrared (IR) cameras with video imaging systems was an attempt to overcome some of the limitations of, traditional video detection. While these IR cameras may improve video detection for some lighting and, temperature conditions, evidence suggested that they do not improve detection performance under all, conditions., The objectives of this research were to,  Determine current TxDOT-specific needs for new vehicle detectors.,  Identify the most promising detectors for both stop line and dilemma zone detection.,  Develop guidelines on each new technology and establish recommended controller and detector, settings to guide TxDOT on installation and use of each detector and combination of detectors.

10727, The connected vehicle research initiative is the core of the U.S. Department of Transportation’s intelligent, transportation system research program. The initiative is beginning to gain momentum in the research, community because of the development of a promising wireless communications technology—dedicated, short-range communications. Connected vehicle technology has the potential to transform the transportation, industry and significantly improve the quality of life of drivers. This study aims to explore the potential uses, of connected vehicle technology in real-world settings., Researchers first conducted a comprehensive review of the state-of-the-art connected-vehicle research and, technologies. Once researchers had a thorough understanding of the technology, they focused on selecting, and developing the near-term practical applications that use connected vehicle technology. The research team, then sought expert opinions from the Texas Transportation Institute working group during two brainstorming, sessions, which produced two lists of potential applications and prioritized the applications based on, deployment feasibility. In particular, a total of five applications were selected for development of the full, concept of operations, including two in safety, two in mobility, and one in environmental security. These, applications address various problems, including wrong-way driving and unprotected-grade-crossing crashes, (safety); work-zone merge efficiency and safety, and freeway speed harmonization (mobility); and slipperypavement, related crashes (environmental security).

Project 0-6390, The Texas Department of Transportation (TxDOT) is challenged with managing a wide range of, transportation safety and operations assets in order to respond to public and other outside interests. These, assets include, but are not limited to pavements, pavement markings, raised pavement markers, structures, roadside signs, traffic signals, roadway illumination, traffic barriers, guard fences, attenuators, maintenance, equipment, vehicles, intelligent transportation systems (ITS) equipment, traffic detection equipment, real, estate, corporate data, and materials. Asset management is a comprehensive strategic approach to, documenting and managing these assets, as well as using information gathered during the process to assist, TxDOT in making cost-effective investment decisions. This project provided TxDOT with guidance on, developing a well-designed asset management system as a critical component of the agency’s approach to, providing for the mobility of its customers, preserving the infrastructure already in place, planning for future, improvements of that infrastructure, and being responsive and accountable to the public regarding the, investment of their tax dollars. This guidance is in the form of a comprehensive Guidebook and a Screening, Tool to help TxDOT quickly identify the best approach for managing assets. Such a system will be an, integral part of TxDOT’s ability to meet its goals of reducing congestion, enhancing safety, expanding, economic opportunity, improving air quality, and increasing the value of transportation assets.

Project 0-6828, Early indications from the use of the newest vehicle detectors for high-speed signalized intersections, suggested that they perform well as replacements for the Texas Department of Transportation’s, (TxDOT’s) legacy systems, but this early conclusion needed verification based on rigorous field testing, in a variety of traffic and environmental conditions. This research investigated the performance, characteristics of detectors designed for the stop line area and indecision zone detection. In some cases, new detectors involved two technologies to cover both upstream and stop line areas. Increasing use of, infrared (IR) cameras with video imaging systems was an attempt to overcome some of the limitations of, traditional video detection. While these IR cameras may improve video detection for some lighting and, temperature conditions, evidence suggested that they do not improve detection performance under all, conditions., The objectives of this research were to,  Determine current TxDOT-specific needs for new vehicle detectors.,  Identify the most promising detectors for both stop line and dilemma zone detection.,  Develop guidelines on each new technology and establish recommended controller and detector, settings to guide TxDOT on installation and use of each detector and combination of detectors.

0-5294, The Texas Department of Transportation (TxDOT) uses ramp control signals (also called ramp meters or, flow signals) to control the rate at which vehicles enter the freeway. This helps TxDOT (1) promote a more, consistent and uniform flow of traffic entering the freeway, and (2) promote a more efficient use of the, existing freeway capacity., The purpose of this project was to develop guidelines and criteria to assist TxDOT decision makers in, determining when and where to install new ramp control signals and remove existing ramp control signals, when they no longer provide a benefit to freeway traffic. This report documents the process, procedures, and, research used to develop those guidelines and criteria. The actual guidelines, criteria, and forms are in, Product 0-5294-P1, “Operating Guidelines for TxDOT Ramp Control Signals.”

Project 0-6029, The objective of this project was to develop three modules that would improve the efficiency of, intersection operations at isolated signalized intersections. The motivation for these modules was to use the, existing detectors more efficiently. This would in turn reduce the number of detectors required at the, intersection and also improve operations in case of detector failures. The adaptive variable initial module, (Module 1) can improve the typical variable initial feature available in most signal controllers by factoring, the turning movements at the intersections in real time along with queue distribution, and activity on, driveways between the detectors and stop bar. The detector failure module (Module 2) develops a rolling, database of phase utilizations of all phases at the intersections. The module uses this database to determine, the appropriate phase time when a detector failure is identified. The variable detector module (Module 3), monitors the phase utilizations on the major-street phase and the volume on the right-turn and left-turn, detectors to vary the delay programmed on detectors to further improve the intersection operations., Researchers evaluated Module 1 and Module 2 and found them improving the intersection operations., However, initial implementations of Module 3 showed limited benefits and only under very rare conditions., Thus, researchers did not develop Module 3 further. Modules 1 and 2 require data that are easily available, within the controller and can be incorporated into the signal controller firmware.

0-6176, The objective of this project is to evaluate the operations at signalized intersections with wide medians in, order to improve safety and efficiency. Intersections with wide medians are characterized by two, intersections and operate differently compared to a typical intersection. Space in the wide median between, the two intersections can be used to store vehicles. However management of the storage space is critical to, avoid queue backing up into the upstream intersection. There are no guidelines specific to operate such, intersections. This results in agencies using their discretion to develop strategies to operate such, intersections, resulting in inconsistent operations. Texas Transportation Institute researchers used VISSIM, simulation model to evaluate numerous strategies that were either in use by TxDOT districts or were, developed by the research team. These strategies were evaluated for various widths of medians, the number, of lanes for the minor street in the median, and the presence of left-turn bays on the major street. The, strategies were also evaluated for low, medium, and high volumes on the major street and on the minor street, as well as different percentages of turning traffic. The research project produced recommended strategies for, various volume and geometric conditions.

Project 0-6402, For intersections with a permissive or protected-permissive left-turn mode, pedestrians cross during the, permissive period. This operation requires the left-turn driver to yield to both opposing vehicles and, pedestrians, prior to accepting a gap and completing the turn. Pedestrian crash risks are increased in these, complicated driving conditions because left-turn drivers sometimes fail to yield to pedestrians., This document summarizes 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. One treatment addressed in, the document is the use of protected or protected-permissive left-turn operation. The guidelines are based on, consideration of pedestrian safety and vehicle operation. These considerations include the road-user costs, associated with pedestrian-vehicle crashes and vehicle delay. The guidelines were incorporated in the Traffic, Signal Operations Handbook. The guidelines were also incorporated into a spreadsheet that was developed, to accompany the Handbook. The Handbook was previously developed for Project 0-5629. It provides, guidelines for timing traffic control signals at intersections that operate in isolation or as part of a, coordinated signal system.

Project 0-5485, The companion guidebook (0-5485-P2) developed as part of this study provides the procedures and, methodologies for effective use of historical incident data at Texas Transportation Management Centers, (TMCs). This research report documents the results from the case studies conducted using the procedures, outlined in the guidebook. Researchers examined the data collected from three Texas TMCs, which are, Houston’s TranStar, Austin’s Combined Transportation and Emergency Communications Center (CTECC), and Fort Worth’s TransVISION. Researchers conducted six categories of analyses in this study – (a) analysis, of incident characteristics, (b) hot spot analysis, (c) incident impact estimation, (d) analysis of incident, management performance measures, (e) incident duration prediction, and (f) incident-induced congestion, clearance time prediction., Researchers found that historical incident data can be effectively used to support incident management and, performance evaluation processes both reactively and proactively. Some procedures need to be automated to, be used efficiently in day-to-day operations. As such, various prototype tools, such as the incident duration, and incident-induced congestion clearance prediction tools, were developed during this study to facilitate and, automate the proposed methodologies. These prototype tools provided a platform for TxDOT to deploy the, research results in the future.

Project 0-6402, "This handbook provides guidelines for timing traffic control signals at intersections that operate in isolation, or as part of a coordinated signal system. The guidelines are intended to describe best practices, as identified, through interviews with engineers and technicians, and to identify conditions where alternative practices are, equally workable. The handbook is intended to make resource investment in signal timing maintenance costeffective, and signal operation more consistent on an area-wide basis. It is likely to be most useful to, engineers that desire quick-response methods for maintaining or improving the operation of existing, signalized intersections., The second edition of the handbook includes new material focused on pedestrian safety at signalized, intersections. One element of the new material is presented as guidelines for determining whether protected, left-turn operation is appropriate based on consideration of pedestrian-vehicle crashes and vehicle delay. A, second element is presented as guidelines for determining whether an exclusive pedestrian phase is needed., A third element is presented as a new appendix that describes alternative pedestrian treatments that can, improve pedestrian safety at signalized intersections."

Project 0-6427, This project defined an approach to integrating data collected and traveler information displayed in a work zone, with a regional transportation management center and/or other state websites. The project conducted a literature, review to define the state of the practice in work zone Intelligent Transportation Systems (ITS; smart work, zones) and worked with the Texas Department of Transportation traffic managers to identify their safety and, mobility needs in a work zone and where ITS can play a role. The research conducted a market review to find, current product offerings that provide solutions to address the identified work zone needs. It also developed two, levels of architecture for integrating work zone ITS data from these products into a regional transportation, management center. The project also explored new uses of work zone information and made recommendations, for operating existing ITS systems in concert with Smart Work Zones.

Project 0-6177, Researchers from the Texas Transportation Institute developed a portable tool consisting of a fieldhardened, computer interfacing with the traffic signal cabinet through special enhanced Bus Interface Units., The toolbox consisted of a monitoring tool and an analysis tool. The monitoring tool monitors and logs, relevant events within the cabinet that provide input to analyze intersection operations. These inputs include, signal status, detector status, preempt status, and coordination status. The user has to provide the basic signal, timing data and coordination data as input data. The analysis tool then analyzes the log files for each day and, produces easy to understand reports. The reports are available either in an hourly average format or, individual cycle format for a selected time period. The measures of effectiveness (MOEs) presented include, phase time, phase failures, queue clearance time, time to service; as well as counts on green, yellow, red, and, split utilization during coordinated operations. Preempt data include the type of preempt, time of preempt, and the duration of preempt for each day. Detector failure data include type of detector failure and the time at, which the detector failure occurred., The analysis tool analyzes the log files and generates user-specified MOEs in Microsoft Excel®, format. This type of format provides the user with an opportunity to further analyze the data in a manner the, user considers appropriate.

0-5326, The primary objective of the research was to identify and evaluate effective ways of improving traffic operations and, safety on congested freeways. There was particular interest in finding condition-responsive traffic control solutions, for the following problem areas: (1) end-of-queue warning, (2) work zones with lane closure, and (3) queue spillover, at exit ramps. Available techniques considered by this research include combination of static and dynamic queue, warning systems, dynamic merge control in advance of freeway lane closures, and various traffic control strategies, such as traffic diversion and ramp metering, to mitigate queue spillover at exit ramps., Three sets of evaluation studies were conducted: first, two queue warning systems deployed on IH 610 and US 59 in, Houston, Texas, were evaluated based on field observations. Second, strategies to resolve a ramp spillover problem at, an exit ramp in El Paso, Texas, were analyzed using traffic simulations. Third, the Dynamic Merge work zone traffic, control concept was evaluated using traffic simulations, and recommendations were developed for its potential use for, various work zone types with different lane closure configurations.