<?xml version="1.0" encoding="utf-8"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>TRB Publications Index</title><link>http://pubsindex.trb.org/</link><atom:link href="http://pubsindex.trb.org/common/TRIS Suite/feeds/rss.aspx?q=&amp;cdatein=1year" rel="self" type="application/rss+xml" /><description></description><language>en-us</language><copyright>Copyright © 2009. National Academy of Sciences. All rights reserved.</copyright><docs>http://blogs.law.harvard.edu/tech/rss</docs><managingEditor>lloyo@nas.edu (Lisa Loyo)</managingEditor><webMaster>lloyo@nas.edu (Lisa Loyo)</webMaster><image><title>TRB Publications Index</title><url>http://pubsindex.trb.org/Images/PageHeader-wTitle.png</url><link>http://pubsindex.trb.org/</link></image><item><title>Sometimes It Pays to Be Lazy When Responding to Freeway Incidents</title><link>http://pubsindex.trb.org/view/1130731</link><description><![CDATA[Traffic Operations Centers (TOC) deal with incidents. These incidents vary by location, time of day, and degree of disruption. Operator responses vary by how quickly they are implemented and the degree of operational actions they take. Operators can react instantaneously, or they can wait to assess the incident’s impact. They can divert traffic from an entire highway or simply implement a mild variable message. The paper presents an analysis of critical incident locations on a test Salt Lake Valley freeway network. The microsimulation modeling is through VISSIM.  We define Closure Level as the percentage of lanes closed due the incident. The Incident Duration is the interval from lane closure to traffic taking back the obstructed lane or lanes. The Response Time is the interval between the onset of the modeled traffic impact and the implementation of the Variable Message Sign Levels (VMS Levels). The VMS Levels are four levels of driver response to the intensity of the message. While no messages are offered, we identify a range of proportion of drivers who comply with diversion recommendations. This paper analyses a wide range of incidents and responses. As expected, the resulting degree of incident disruption is mitigated by the speed of response and the proportion of drivers who divert. However, for certain minor incidents, a “laid back” approach is the better option. This counter intuitive finding can be characterized as “too much diversion, too soon, for too many drivers”.]]></description><pubDate>Wed, 08 Feb 2012 17:22:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1130731</guid></item><item><title>Driving Behavior in case of Emergency Situations: A Psycho-spacing Modeling Approach</title><link>http://pubsindex.trb.org/view/1129734</link><description><![CDATA[Emergency situations have a large impact on society. Simulation software packages have been developed aiming to simulate traffic flow operations in case of these situations. However, it is not yet clear which adaptation effects in empirical longitudinal driving behavior can be observed. Furthermore, it is not yet clear to what extent these adaptation effects in case of emergency situations are represented in current car-following models. To this aim a driving simulator experiment intending to induce longitudinal driving behavior under emergency conditions was performed. Longitudinal driving behavior was measured through registered behavior in the driving simulator and analyzed using a Multivariate Analysis of Variance. So-called action points in psycho-spacing models were estimated using a new data analysis technique. Also acceleration as well as ’jumps’ in acceleration at action points were determined using a Multivariate Regression Analysis. The results show that substantial and significant adaptation effects in longitudinal driving behavior can be observed in case of an emergency situation. Furthermore, the results show substantial differences in the position of action points in the (∆v, s) plane in the psycho-spacing model between normal driving conditions and emergency conditions as well as substantial differences in acceleration and ’jumps’ in acceleration at these action points. The contribution is concluded with a discussion section as well as recommendations for future research.]]></description><pubDate>Wed, 08 Feb 2012 17:09:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1129734</guid></item><item><title>Barrier-Free Ring Structures and Pedestrian Overlaps in Signalized Intersection Control</title><link>http://pubsindex.trb.org/view/1129647</link><description><![CDATA[Compared to the ring-barrier framework used for ring structures (or “phasing plans”) in signalizing intersection control in the United States, the Dutch framework has no explicit barriers, but only a requirement to respect pairwise conflicts. This paper describes how ring structures can be modeled using pairwise conflicts as a starting point. The authors extend modeling techniques to account for offset constraints such as leading pedestrian intervals (LPI’s) in which the start or end of one traffic movement is constrained by the start or end of another movement that is otherwise compatible. One drawback of the more flexible Dutch framework is that it permits many more possible ring structures, and it can be prohibitive to evaluate them all manually. They describe VRIGEN, a new, automated method for identifying and evaluating all possible ring structures that overcomes this drawback. Finally, the authors present several examples in which barrier-free ring designs allow signals to cycle more quickly and efficiently, with safety and delay improvements to pedestrians and bicyclists. Most of these examples include pedestrian phases that overlap one another, recognizing that pedestrian phases don’t conflict with each other and therefore one shouldn’t have wait for each other.]]></description><pubDate>Wed, 08 Feb 2012 17:08:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1129647</guid></item><item><title>Anticipatory Traveler Information System for Freeway Arterial Networks in Shanghai, China</title><link>http://pubsindex.trb.org/view/1130788</link><description><![CDATA[Variable message signs (VMS) can be used to divert traffic to less congested areas of road networks and enhance network performance. However, ensuring increased acceptability of the suggested guidance and improving the credibility of VMS information among drivers are crucial objectives. This paper aims to develop a real-time behavior-consistent anticipatory traveler information system based on VMS and design novel network-level guidance signs for Shanghai, China. A target objective is for the system to be equipped with the capability to provide dynamic route guidance for en-route travelers and perform the calibration of real-time drivers' en-route diversion behavior. The system should also facilitate the formulation of VMS-based route guidance control strategies consistent with drivers' en-route diversion behavior, enabling the agencies responsible to exploit the data obtained from the system's license plate readers, loop detectors, and other traffic data collection devices. The proposed system is designed to contend with most of the critical issues associated with real-time operations, including the automated calibration of the parameters of a time-variant traffic behavior model using aggregate-level data, data cleaning and reliable estimation of missing data, and spatio-temporal coordination and integration in VMS-based routing strategies. The implementation results demonstrate that the route guidance information displayed by the proposed system is well received by drivers. The findings also reveal that the integrated and coordinated VMS-based traffic routing information effectively provides guidance to drivers, and encourages better use of roadway capacity, thereby resulting in better system performance over the same period of operations.]]></description><pubDate>Wed, 08 Feb 2012 17:23:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1130788</guid></item><item><title>Naturalistic Car Driver Behavior: Hybrid Wiedemann and Gazis-Herman-Rothery Model Calibration</title><link>http://pubsindex.trb.org/view/1130583</link><description><![CDATA[This research effort combines the Wiedemann car-following model with the GHR car-following model for car drivers using The Naturalistic Car Driving Study’s data collected by the Virginia Tech Transportation Institute (VTTI).  From past research efforts, it can be seen that the GHR model calibrates differently depending upon the situations that drivers face.  The Wiedemann model uses thresholds in order to divide car-following into different regimes.  These regimes represent different situations which correspond to a particular action to be taken.  When the two models are combined, the Wiedemann model defines the different regimes while the GHR model calculates the accelerations based on those regimes.  In this way, the two models work together in order to clarify the intended action of the driver as a result of different situations.  The results of this combination along with the Naturalistic Data of five drivers show a difference in behavior between the drivers and presents a measure of the attentiveness of different drivers.  The results show that the Hybrid model has an ability to be more independent of the actions of the lead vehicle. This is a valuable trait that is reflected in the data of some of the drivers.]]></description><pubDate>Wed, 08 Feb 2012 17:20:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1130583</guid></item><item><title>Evaluation of Transit Signal Priority Options for Future 5600 W Bus Rapid Transit Line in West Valley City, Utah</title><link>http://pubsindex.trb.org/view/1130717</link><description><![CDATA[This paper presents an analysis of different Transit Signal Priority (TSP) for a future Bus Rapid Transit (BRT) corridor in West Valley City, UT. The goal is to find the optimal TSP strategy for estimated and planned traffic and transit operations. The study uses VISSIM microsimulation software in combination with ASC/3 Software-in-the-Loop (SIL) simulation. Four different models were used in the analysis: No TSP, TSP, TSP with phase rotation and Custom TSP. The results show that TSP with phase rotation and Custom TSP can both be considered for implementation. TSP with phase rotation brings significant benefits for BRT, with minimum impacts on vehicular traffic. Custom TSP brings major benefits for BRT in terms of travel times, delays and stops. However, this strategy has more impacts on vehicular traffic. Custom TSP is an advanced strategy that still needs examination and improvement. The study provides a set of instructions on how the described strategies can be implemented in the field traffic controllers.]]></description><pubDate>Wed, 08 Feb 2012 17:22:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1130717</guid></item><item><title>Leveraging Information Technology for Balanced Scorecard Prototyping and Implementation: State Department of Transportation Case</title><link>http://pubsindex.trb.org/view/1130736</link><description><![CDATA[The objective of this study is to apply the Balanced Scorecard (BSC) framework to develop a conceptual strategic performance measurement system leveraging an integrated ERP system for a state Department of Transportation (DOT). Analysis of DOT literature, site visits with an anonymous DOT, and interviews with relevant DOT employees were used to derive the Balanced Scorecard framework and software prototype design. A case and an automated software prototype were developed and used to illustrate the Balanced Scorecard development process for a state department of transportation (DOT).  The prototype emphasizes the appearance and interpretability of the balanced scorecard data to address accountability, traceability, timeliness of information, continuous improvement, and data visualization to address issues facing DOT’s strategic planning and performance measurement. This research contributes to development of best strategic performance measurement practices in a state DOT.  The generalized framework, when combined with Information Technology, contributes a starting point for customization, as well as uniformity for a best business practice. Furthermore, this study is one of few studies that utilized ERP technology to propose a generalized framework that addresses the need for comparative studies, continuous improvement, sharing best business practices, implementation of best business practices, collaboration, learning and growth, and ubiquitous recognition of strategic mission of Departments of Transportation.]]></description><pubDate>Wed, 08 Feb 2012 17:22:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1130736</guid></item><item><title>Estimating a Road Mask to Improve Vehicle Detection and Tracking in Airborne Imagery</title><link>http://pubsindex.trb.org/view/1129706</link><description><![CDATA[This research proposes a method to estimate a road mask in airborne imagery to improve vehicle detection and tracking. The road mask can remove false detections and reduce the computation time. The road mask is estimated based on the smoothed positions of vehicles tracked by the short-term and long-term trackers in the software tool TRAVIS in a fixed number of frames, i.e., one cycle. Firstly, raw vehicle positions obtained from TRAVIS are smoothed using a Kalman filter. Secondly, the slope of the roadway is estimated based on the smoothed positions of these vehicles. Thirdly, falsely detected vehicles are removed based on the criterion that the slope of the lines connecting two vehicles in the same lane should be close to the slope of roadway. Finally, the road mask is generated according to the minimal and maximal intercepts of the approximated roadway edges in one cycle. Experimental results show that the estimation of the road mask is accurate and that the improvement of the correct detection and tracking rate and the computation time is significant.]]></description><pubDate>Wed, 08 Feb 2012 17:08:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1129706</guid></item><item><title>Development of Travel Time Data Quality Hypothesis Test</title><link>http://pubsindex.trb.org/view/1130714</link><description><![CDATA[The accuracy of travel time data generated by Traveler Information Systems (TIS) is a topic of interest for transportation engineers. A number data quality evaluations have been conducted in recent years to try and measure the accuracy of these systems. In general, the approach taken has been to quantify errors from the system by measuring the distance between an estimate and a benchmark or “ground truth” value. A number of distance-based metrics have been used including average error bias, absolute average error, and root mean squared error. However, because the benchmark values are random values, the errors are also random and subject to some uncertainty. This paper proposes a novel approach to measuring errors such that the distribution of the errors can be quantified and a statistical hypothesis test can be constructed. The hypothesis test can be used to decide whether or not the system is operating at the desired level of accuracy.]]></description><pubDate>Wed, 08 Feb 2012 17:22:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1130714</guid></item><item><title>Using GPS Data Collected in Household Travel Surveys to Assess Physical Activity</title><link>http://pubsindex.trb.org/view/1130495</link><description><![CDATA[Transportation planners have an increasing interest in identifying transportation investment solutions that encourage healthy living.  Once the domain of health professionals, physical activity studies are being considered by transportation agencies. The use of Global Positioning System (GPS) data collection in tandem with traditional travel survey methods and physical activity studies has become commonplace in each discipline over the past decade as researchers and practitioners seek technology solutions to address issues associated with increasing respondent burden and decreasing response rates. GPS technology used as a passive, objective measure of both travel and physical activity results in the collection of highly accurate, incredibly detailed data that could never be supported by self-report survey methods.  The level of detail provided by GPS, while incapable of identifying some instances of physical activity, provides an accurate and useful assessment of active transport.  Agencies wishing to encourage healthy living can use research results regarding active transport to evaluate the effectiveness of certain transportation investments.  To demonstrate, GPS travel data from the Massachusetts Statewide Travel Survey is used to identify and evaluate segments of active transport. The GPS travel data is then used to evaluate whether the presence of transit options near home, work and/or school locations have a positive impact on health.]]></description><pubDate>Wed, 08 Feb 2012 17:19:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1130495</guid></item><item><title>Development and Evaluation of an Algorithm for Resolving Conflicting Transit Signal Priority Calls</title><link>http://pubsindex.trb.org/view/1130662</link><description><![CDATA[The goal of this paper is the development and evaluation of an algorithm for resolving conflicting Transit Signal Priority (TSP) requests. This algorithm was designed to work with actual traffic controllers, without the need of new hardware or software installations. It was tested in VISSIM microsimulation and ASC/3 Software-in-the-Loop (SIL) controllers on an actual intersection which will be upgraded to serve two conflicting Bus Rapid Transit (BRT) lines. The ASC/3 logic processor was used to control built-in TSP in the case of conflicting requests, and to develop custom TSP strategies that do not rely on built-in TSP. Custom TSP provides a much higher level of TSP for transit vehicles then the built-in TSP, and it creates opportunities for more adaptable TSP control.  The results show that the widely used first-come first-served policy for resolving conflicting TSP requests is not the best solution. It can perform worse than if no priority is provided. For the analyzed intersection, this option even increased BRT delays by 13% over the no TSP option. The presented algorithm can help resolve the problem of the conflicting TSP requests. It works best when combined with several TSP strategies. For the custom TSP strategies, the application of the algorithm reduces BRT delays for more than 30%, with minimal impact on vehicular traffic. The algorithm shows promising results, and with small upgrades it can be applied to any type of TSP.]]></description><pubDate>Wed, 08 Feb 2012 17:21:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1130662</guid></item><item><title>Use of Cell Phone Network Data in Traffic Data Collection and Long-Haul Truckshed (Geographic Extent) Tracking</title><link>http://pubsindex.trb.org/view/1130880</link><description><![CDATA[This study analyzed the potential of cell phone positioning techniques in freight trucks data collection and long-haul truckshed (geographic extent) tracking.  The freight truck identification and tracking algorithms were developed by means of cell phone network data and the established freight truck analysis GIS to recognize the freight trucks and determine their geographic extent (trucksheds).  A case study was conducted to illustrate the truckshed tracking process and verify the tracking result from the cell phone network. Cell phones leaving from the test logistics distribution center were tracked and classified based on the developed tracking algorithms. The case study also demonstrated the processes of determining the geographic extent and traffic impact on the transportation network from the test logistics distribution center. The results found that the proposed tracking algorithms can identify a similar percentage of freight truck data from the test facility.  The analysis of geographic extent indicated that 60 percent of freight traffic stayed within 30 miles from the facility, and approximately 20 percent of the traffic was considered long-haul freight traffic traveling more than 80 miles away.  The long-haul tracking results found that most of the long-haul trucks returned to the original test facility during the same day. It is recommended that the tracking algorithms and data analysis process can also be applied to any other freight trucking terminal or intermodal transportation facility as long as the cell phone network data are available.  A complete freight GIS analysis network around the study area is also recommended before processing the study.]]></description><pubDate>Wed, 08 Feb 2012 17:24:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1130880</guid></item><item><title>Effects of Open Road Tolling on Safety Performance of Freeway Mainline Toll Plazas</title><link>http://pubsindex.trb.org/view/1130546</link><description><![CDATA[Advances of Intelligent Transportation Systems (ITS) technologies promoted the implementation of open road tolling (ORT) on tolled freeways worldwide. This new tolling solution converts existing barrier tollbooths to express lanes capable of collecting tolls at high-speeds. ORT has demonstrated numerous benefits in reducing traffic congestion and air pollution. However, effects of ORT on safety are still not clear, as most of ORT systems have only been operated for a relatively short period of time. Therefore, this study aims to evaluate the safety impacts of ORT by studying locations where such tolling solution was recently deployed on the Garden State Parkway in New Jersey. Multiple-year crash data at the toll plazas before-after the implementation of the ORT systems were used for analysis. Full Bayes methodology is employed to estimate crash frequency models as a function of traffic and toll plaza configurations. These models were used to estimate the crash frequency assuming that the ORT systems were not installed. Then, these estimations were compared with the observed number of crashes occurred after the deployment of the ORT systems. Individual comparisons show that crash reductions are observed at most of the toll plazas. The overall comparison shows that crashes at locations where ORT systems were deployed are decreased by about 24 percent after deployment of these systems. It can thus be concluded that the use of ORT is a beneficial solution towards improving toll road safety. From an implementation point of view, the analyses results indicate that special attention should be paid to operational elements such as signage, diversion and merge designs of the ORT systems.]]></description><pubDate>Wed, 08 Feb 2012 17:20:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1130546</guid></item><item><title>Impacts of Centerline and Shoulder Rumble Strips on Vehicular Lateral Lane Position and Passing Maneuvers on High-Speed Two-Lane Rural Roadways</title><link>http://pubsindex.trb.org/view/1130730</link><description><![CDATA[A before-and-after field evaluation was performed to assess the impacts that centerline and shoulder rumble strips on rural two-lane roadways have on various characteristics of driver behavior.  The following characteristics were assessed as part of this evaluation:  passing maneuvers, lateral lane placement, and centerline and edgeline encroachments.  The data were collected using video cameras that were temporarily installed at 18 passing zone locations and 12 curve locations on rural two-lane roadways throughout Michigan.  The cameras were installed at the same locations both before and after the installation of rumble strips.  A manual review of the videos was performed to assess the various behavioral characteristics.  Nearly 78,000 vehicles were observed during review of the passing zone videos, while more than 50,000 vehicles were observed during review of the curve videos.  Centerline rumble strips were found to improve drivers’ central lane positioning tendencies and decrease the occurrence of centerline encroachments.  The inclusion of shoulder rumble strips in addition to centerline rumble strips provided incremental improvements in central lane positioning, while also reducing edgeline encroachments.  Most notably, centerline and shoulder rumble strips greatly reduced the occurrence of drivers laterally shifting to the inside (i.e., “corner cutting”) while maneuvering through curves.  Additionally, centerline rumble strips did not reduce the rate of passing maneuvers.  Collectively, these results suggest that both centerline and shoulder rumbles strips have a positive impact on surrogate measures for roadway safety, while providing no negative impacts to driver behavior.]]></description><pubDate>Wed, 08 Feb 2012 17:22:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1130730</guid></item><item><title>Preliminary Development of Methods to Automatically Gather Bicycle Counts and Pedestrian Delay at Signalized Intersections</title><link>http://pubsindex.trb.org/view/1129627</link><description><![CDATA[The increase of bicycle and pedestrian traffic in many urban areas has led to growing interest in multimodal performance measures.  Traditionally, counts of pedestrians and bicycles have only been collected for short durations at spot locations.  The lack of reliable long-term data precludes systematic performance monitoring and analysis of trends. This paper summarizes preliminary efforts to develop a long-term monitoring and collection system that leverages existing infrastructure to monitor  bicycle and pedestrian activity. Communication and logic protocols have been implemented to gather bicycle counts and pedestrian delay using existing hardware (loop detectors, signal controllers) and software at select intersections within the City of Portland, Oregon. Bicycle counts are being gathered using advance loops in bike lanes. Two novel methods for collecting pedestrian delay at signalized intersections are proposed in this paper. One method uses transit priority logging feature in the traffic controller software to track individual pedestrian phase actuations and corresponding delay. The other method uses internal logic commands to capture pedestrian delay estimates in relevant bins. Both methods provide delay and number of pedestrian actuations which can be used to characterize the pedestrian LOS at an intersection. The results from the study reveal that automation of data collection techniques for generating multimodal performance measures can assist in analyzing performance and long-term trends. The methods developed in this study can benefit other regions in understanding the effects of signal timing settings on multimodal performance.]]></description><pubDate>Wed, 08 Feb 2012 17:07:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/1129627</guid></item></channel></rss>
