<?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?s=PHNlYXJjaD48cGFyYW1zPjxwYXJhbSBuYW1lPSJsb2NhdGlvbiIgdmFsdWU9IjIiIC8%2BPHBhcmFtIG5hbWU9InN1YmplY3Rsb2dpYyIgdmFsdWU9Im9yIiAvPjxwYXJhbSBuYW1lPSJ0ZXJtc2xvZ2ljIiB2YWx1ZT0ib3IiIC8%2BPC9wYXJhbXM%2BPGZpbHRlcnM%2BPGZpbHRlciBmaWVsZD0ia2V5d29yZHMiIHZhbHVlPSIoJnF1b3Q7cGxvdyomcXVvdDsgT1IgJnF1b3Q7c2FsdComcXVvdDsgKSBBTkQgJnF1b3Q7c25vdyByZW1vdmFsJnF1b3Q7IiBvcmlnaW5hbF92YWx1ZT0iKHBsb3cqIE9SIHNhbHQqKSBBTkQgJnF1b3Q7c25vdyByZW1vdmFsJnF1b3Q7IiAvPjwvZmlsdGVycz48cmFuZ2VzIC8%2BPHNvcnRzPjxzb3J0IGZpZWxkPSJwdWJsaXNoZWQiIG9yZGVyPSJkZXNjIiAvPjwvc29ydHM%2BPHBlcnNpc3RzPjxwZXJzaXN0IG5hbWU9InJhbmdldHlwZSIgdmFsdWU9InB1Ymxpc2hlZGRhdGUiIC8%2BPC9wZXJzaXN0cz48L3NlYXJjaD4%3D" rel="self" type="application/rss+xml" /><description></description><language>en-us</language><copyright>Copyright © 2015. National Academy of Sciences. All rights reserved.</copyright><docs>http://blogs.law.harvard.edu/tech/rss</docs><managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor><webMaster>tris-trb@nas.edu (Bill McLeod)</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>Evaluating Signal Preemption Requests in Utah Using Vehicle-to-Everything Dedicated Short-Range Communication Equipped Snowplows</title><link>http://pubsindex.trb.org/view/2319892</link><description><![CDATA[At the start of the 2019 to 2020 snow season, vehicle-to-everything (V2X) systems using dedicated short-range communication (DSRC) were placed on Utah Department of Transportation snowplows and traffic signal controllers on selected state routes. This study was conducted to understand the overall impacts of snowplows using V2X DSRC to request signal preemption. Roadside units (RSUs) were deployed on five corridors throughout the Salt Lake metropolitan area. Similar routes without RSUs were selected as a control and were used in the analysis to quantify results. Each snowplow on these corridors was equipped with an onboard unit (OBU). Based on data collected, analysis was performed on both traffic signal performance and vehicle performance data. Within the traffic signal performance analysis, it was found that the V2X DSRC system was utilized often, with snowplows requesting preemption in more 50% of the occasions they approached a signalized intersection. Of those requests, signal controllers granted preemption in over 80% of cases. On average, signal controller coordination was affected for less than 5?min. The vehicle performance analysis found that the snowplows on equipped routes had travel speeds that were less affected when there was snow than on corresponding not-equipped routes. Vehicle crash data also showed that there was a greater decrease in crashes on equipped routes than not-equipped routes. Anecdotal evidence gathered from snowplow drivers indicated that snowplows stopped less when using signal preemption. Drivers also noted a benefit to overall snow removal operations on corridors equipped with the V2X DSRC system.]]></description><pubDate>Thu, 11 Jan 2024 17:02:48 GMT</pubDate><guid>http://pubsindex.trb.org/view/2319892</guid></item><item><title>Effectiveness of Green Warning Lights with Different Flashing Patterns for Winter Maintenance Operations</title><link>http://pubsindex.trb.org/view/1850045</link><description><![CDATA[Snow removal activities are performed by roadway agencies to enhance winter mobility and safety. Slower travel speeds during these operations, combined with low visibility and reduced pavement friction, mean that safety and collision avoidance remain a persistent concern. Many studies have implemented signing and lighting technologies to improve the visibility of snowplows. Although a few studies have evaluated the use of different colors on snowplows, there is no rigorous study that evaluates the potential impacts of using green warning lights for winter maintenance operations. This study, therefore, investigates the impacts of various warning light configurations on the visibility of snowplows, with the focus on green lights. To this end, 37 warning light configurations are designed using various color combinations (green and amber), and flashing patterns (single and quad) on the back (LED), the top (beacon), or both, of snowplows. These configurations are evaluated to identify the most effective configurations. Three sets of experiments are designed and implemented: static, dynamic, and weather to evaluate the visibility effectiveness in different contexts: day versus night, clear versus snowy weather, and static versus dynamic scenarios. Human subjects are employed to conduct the experiments and the test results are evaluated using statistical analyses. The conspicuity during the day time and glare during the night time are statistically different among various configurations. In addition, adding green lights with a single flash pattern to amber warning lights improves the conspicuity, while keeping the glare at an acceptable level relative to configurations using only amber.]]></description><pubDate>Tue, 11 May 2021 12:23:39 GMT</pubDate><guid>http://pubsindex.trb.org/view/1850045</guid></item><item><title>Friction and Snow–Pavement Bond after Salting and Plowing Permeable Friction Surfaces</title><link>http://pubsindex.trb.org/view/1739259</link><description><![CDATA[Open graded, ultrathin, and permeable friction course surfaces (collectively referred to as PFSs) have been successfully used by many transportation agencies in several countries as a wearing surface to help reduce water splash and spray, reduce potential for hydroplaning, increase friction, and reduce noise. Despite these advantages, when used in colder climates PFSs tend to freeze more rapidly, transport deicing/anti-icing chemicals from the road surface, clog from sands and other debris, and retain snow and ice for a longer period of time. Most of the reported difficulties with PFSs are at near-freezing temperatures (28°F–35°F). Laboratory tests were conducted using samples of traditional dense graded pavement (DGP), cores from new and old in-service open graded friction course pavements, and ultrathin friction course samples made from hot mix asphalt collected from paving operations. The tests were conducted in a walk-in environmental chamber at 28°F. Snow–pavement bond strength and static friction were measured to determine the effectiveness of anti-icing with salt brine and deicing with dry and pre-wet solid salt. The test results revealed that compacted snow bonds more strongly to PFSs, yet friction of PFSs was significantly greater than DGPs after snow removal, even without the use of salt. The PFSs appeared more white and snowy, and this appearance may be contributing to unnecessarily high application rates of salt by practitioners. Field testing is recommended to better understand the frictional behavior of PFSs during a variety of winter storm conditions and deicer application strategies.]]></description><pubDate>Mon, 21 Sep 2020 16:43:55 GMT</pubDate><guid>http://pubsindex.trb.org/view/1739259</guid></item><item><title>Role of Route Optimization in Benefiting Winter Maintenance Operations</title><link>http://pubsindex.trb.org/view/1495507</link><description><![CDATA[For winter maintenance purposes, the Ohio Department of Transportation (ODOT) deploys a fleet of approximately 1,600 snowplow trucks that maintain 43,000 lane miles of roadway. These trucks are based out of 200 garages, yards, and outposts that also house a combined total of 650,000?tons of salt. The deployment of such a large number of trucks over a vast maintenance area creates an operational problem in determining the optimal maintenance routes and fleet size. Traditionally, ODOT has used county borders as maintenance boundaries for ODOT garages. However, by removing these borders and optimizing the snowplow routes, ODOT may benefit from significant time and cost savings. The results of this project provide ODOT a tool to determine the minimum number of trucks needed to maintain the necessary roadways within Districts 1, 2, and 10. In addition, the project recommends to ODOT a tool to assign assets to specific facilities and the most optimal routes for each truck in a district. This research indicates the possibility of reducing the fleet size within Districts 1, 2, and 10 by a total of 29 trucks while maintaining the same level of service. Apart from fleet size reduction, the route optimization can decrease the amount of time in which to treat each road in the three districts by 17?hours for one iteration.]]></description><pubDate>Fri, 30 Mar 2018 09:50:07 GMT</pubDate><guid>http://pubsindex.trb.org/view/1495507</guid></item><item><title>Cost–Benefit Analysis of Using the Tow Plow for Winter Maintenance</title><link>http://pubsindex.trb.org/view/1494730</link><description><![CDATA[Several relationships between winter maintenance cost elements (direct cost such as labor, material, equipment and indirect cost such as travel delay) and snow storm severity (in terms of snow amount) were developed for two equipment fleet configurations. These configurations included Tow Plows present in the equipment fleet and Tow Plows absent in the equipment fleet. Analysis of these two equipment configurations identified the benefits of using Tow Plows in the equipment fleet for six-lane and four-lane freeways in Michigan at different winter storm severity levels. The developed relationships (based several different four- and six-lane lane freeway routes) were used to develop the most effective equipment fleet configurations for different Michigan Department of Transportation (MDOT) snow routes. Finally, the cost effectiveness of including Tow Plows in the equipment fleet was analyzed using direct cost and the total cost including delay costs. Results show substantial cost savings on the direct cost as well as total cost (including delay cost) if the recommended equipment configuration is employed.  Use of Tow Plow in the equipment fleet cleared the roadways faster, and the delay costs due to winter storms were greatly reduced. The equipment fleet configuration with Tow Plows can be modified to realize direct cost savings with the use of less regular plows as recommended in this paper.]]></description><pubDate>Thu, 22 Mar 2018 11:57:27 GMT</pubDate><guid>http://pubsindex.trb.org/view/1494730</guid></item><item><title>Maintenance Services, Transportation Weather, and Winter Maintenance</title><link>http://pubsindex.trb.org/view/1461078</link><description><![CDATA[This issue contains ten papers concerned with maintenance services, weather, and winter maintenance. Specific topics addressed in this issue include the following:  ice melting capacity; relating public opinion of roadway assets to field data; project prioritization; grouping of pavement and bridge projects; snow fences; microsimulation modeling of traffic in inclement weather; snow removal performance metrics; prewetting brines and mixing on ice-melting rate of salt; and anti-icing technology and crash reduction.]]></description><pubDate>Wed, 29 Mar 2017 08:41:18 GMT</pubDate><guid>http://pubsindex.trb.org/view/1461078</guid></item><item><title>A Survey on the Current Practices in Clearing Various Interchange and Intersection Configurations</title><link>http://pubsindex.trb.org/view/1439116</link><description><![CDATA[Interchanges and intersections are the most complex part in a roadway network and are very challenging for snow plowing operators. Currently, no detailed practice manuals are available for clearing interchanges and intersections. To address the needs for practical winter maintenance operations, ClearRoads initiated a research project to develop a training video based on the best practices for snow removal and ice control on interchange and intersection layouts. As part of the project, a survey study was conducted to gather information on the current practices of agencies in the U.S. on clearing ten types of interchange and intersection layouts. This paper presents the survey results and findings. The findings indicate that single and tandem-axle trucks with front plows are the commonly used by agencies. Tow plows were reported to be successful in clearing diverging diamond interchanges and directional T interchanges, but have limitations in clearing roundabouts. Diagram depicting example plowing patterns were provided for comments from survey respondents. The majority of the respondents accepted the examples, therefore, they will be considered as the best practices to be included in the training video. Although the best practice example for each interchange/intersection is different, some general rules were summarized from the survey findings: e.g. avoid plowing snow into highly elevated side to mitigate melting and freezing of snow across the road and square the plow at intersections and overpasses to avoid dragging snow onto already cleared lanes.]]></description><pubDate>Mon, 27 Feb 2017 17:12:24 GMT</pubDate><guid>http://pubsindex.trb.org/view/1439116</guid></item><item><title>Issues in the Planning and Management of Roundabouts in Cold, Snowy Regions: Traffic capacity
reduction at a roundabout with a compacted-snow road surface, and
truck apron design that considers snow removal</title><link>http://pubsindex.trb.org/view/1437414</link><description><![CDATA[Two-thirds of Japan is classified as cold and snowy. When roundabouts are planned and managed, snow must be considered. In this study, first the reduction in traffic capacity was determined for a roundabout with a snow-covered surface on a test track. Vehicle gap parameters were measured at a roundabout. These parameters were critical gap time (tc), follow-up time (tf) and minimum headway time for vehicles on the roundabout’s circulatory roadway (ɾ). When the roundabout had a compacted-snow surface, the entry capacity was about 300 vehicles/hour less than when it had a dry surface. However, when the surface was compacted snow spread with non-slip abrasives, the entry capacity was reduced by only about 150 vehicles/hour from that for the dry road surface.  Next, tests were conducted on damage to the truck apron structure from snow removal operations. Three types of apron with various height and angle conditions were tested in terms of damage to the apron from contact by snow removal machinery. The types were four conventional stepped aprons, one step-and-gradient apron, and four gradient aprons (i.e., a total of nine aprons). The tested snow removal vehicles were a wheel loader and a motor grader. The gradient aprons were found to be damaged less than the other types of aprons. This paper discusses issues to be addressed in the planning and operation of roundabouts in cold, snowy regions, specifically their decreased flow rate when covered with compacted snow and designs for their aprons that resist damage from snow removal machinery.]]></description><pubDate>Mon, 27 Feb 2017 09:25:49 GMT</pubDate><guid>http://pubsindex.trb.org/view/1437414</guid></item><item><title>Development of a Finite Element Model for Electrically Conductive Concrete Heated Pavements</title><link>http://pubsindex.trb.org/view/1439124</link><description><![CDATA[An electrically conductive concrete (ECON) heated pavement system (HPS) is a promising snow and ice removal technology for airports presenting advantages of enhanced safety for ground crew servicing the aircraft, reduced dependency on deicing salts, and minimal use of snow removal equipment. ECON works by applying an electrical current through electrodes embedded into the ECON layer to generate heat generated by resistive losses to melt ice/snow on paved surfaces. A 3-D FE model of the ECON slab (122 cm long x 86 cm wide x 10 cm thick) built at Iowa State University (ISU) was developed and validated through comparison with experimental test results produced by using decoupling thermal-electrical analysis of a phenomenon described as joule heating. The results demonstrate that the developed 3-D FE modeling approach can be utilized as a cost-effective evaluation tool for examining effects of various design parameters on the time-dependent ECON heating performance for ECON HPS design optimization.]]></description><pubDate>Mon, 13 Feb 2017 17:19:55 GMT</pubDate><guid>http://pubsindex.trb.org/view/1439124</guid></item><item><title>Field Test of Visibility Markers for Snow Maintenance Equipment</title><link>http://pubsindex.trb.org/view/1437902</link><description><![CDATA[Due to the evolution of the use of private contractors in Ontario for highway snow removal a lack of consistency developed in the lighting and marking of maintenance vehicles. Due to safety concerns raised by operators of snow removal equipment, the Ministry of Transportation of Ontario (MTO) initiated the development  of an  updated  standard  for  a  lighting  and  marking  system,  to  produce  greater visibility/conspicuity of, and safety for, highway snow removal equipment and associated workers. The standard was developed through a multi-disciplinary value engineering study. This paper describes a series of tests that were carried out to assess the proposed lighting and marking system. Tests involved selection of highly conspicuous elements, determination of the conspicuity of brake lights, turn signals and rotators, in the presence of other system elements and assessment of driver ability to determine closing speed with the proposed system. The final standard included: A fluorescent yellow-green/black checkerboard with Type III/IV sheeting; Constant Amber + Flashing Blue LED light bars to each side and above the checkerboard; Red and white retro-reflective tape on an airfoil above the checkerboard; Upper and lower tail and brake lights; and Amber and blue rotating beacons, one on the roof of the cab and the other two near the top left and top right corners of the back of the snow removal equipment. This design has now been accepted and published as a national guideline by the Transportation Association of Canada.]]></description><pubDate>Mon, 30 Jan 2017 09:54:08 GMT</pubDate><guid>http://pubsindex.trb.org/view/1437902</guid></item><item><title>Maintenance Services, Transportation Weather, and Winter Maintenance</title><link>http://pubsindex.trb.org/view/1375597</link><description><![CDATA[This issue contains 17 papers concerned with maintenance services, transportation weather, and winter maintenance.  Specific topics covered in this issue include fleet preventive maintenance practices; fuel use and emissions for heavy-duty diesel maintenance equipment; pavement marking service life; and performance-based pavement marking maintenance contracts.  Additional topics include:  satellite salt facility location; solution-induced weakening of compacted snow; winter road surface condition monitoring; ice formation and the effectiveness of deicing agents; prewetting brines; and icing management on a bridge’s stay cables.  This issue also includes papers on the impact of inclement weather on freeway traffic speed; weather conditions and snow removal operations on urban travel speed; fixed automated spray technology systems; the influence of weather on transport demand; cross-asset transportation project coordination; safety performance of urban arterials with lightning; and a multiple-step traffic speed forecasting strategy for winter freeway operations.]]></description><pubDate>Wed, 25 Nov 2015 08:33:48 GMT</pubDate><guid>http://pubsindex.trb.org/view/1375597</guid></item><item><title>Effects of Weather Conditions and Snow Removal Operations on Travel Speed in an Urban Area</title><link>http://pubsindex.trb.org/view/1336703</link><description><![CDATA[In Sapporo, Japan, the effective number of lanes in winter was decreased by some snow removal operations (plowing) and increased by others (hauling); the average speed of vehicles in February 2013 (winter) was about 10 km/h slower than in October 2013 (autumn). In other words, the roads are more prone to traffic congestion in winter than in the other seasons. The objective of this study was to investigate the effects of weather conditions and snow removal operations on travel speed to determine the causes of winter traffic congestion in Sapporo. Four steps were performed to identify the relationships between traffic, weather, and snow removal operation factors. The first step was to establish a data set for analysis by combining traffic, weather, and snow removal operation data. The second step was to develop multiple linear regression (MLR) models with all the variables. The third step was to investigate the periodicity of the residuals to apply autoregressive integrated moving average (ARIMA) models between the actual and predicted values of the MLR models. Then, ARIMA models or seasonal ARIMA (SARIMA) models were developed, depending on the periodicity. The fourth step was to combine the R-squares of the MLR and ARIMA models. It was found that the explanatory power of the speed prediction model was improved by combining the two models. As a result of applying the ARIMA and SARIMA models at the residuals, the R-squared values increased by .60.]]></description><pubDate>Tue, 27 Jan 2015 11:23:54 GMT</pubDate><guid>http://pubsindex.trb.org/view/1336703</guid></item><item><title>Tungsten Carbide for Snowplow Blades</title><link>http://pubsindex.trb.org/view/1308167</link><description><![CDATA[No abstract available.]]></description><pubDate>Wed, 07 May 2014 11:18:22 GMT</pubDate><guid>http://pubsindex.trb.org/view/1308167</guid></item><item><title>Strategies for Snow and Ice Control at Extreme Temperatures: Review of Current Practice</title><link>http://pubsindex.trb.org/view/1289150</link><description><![CDATA[Extremely cold winter storms (below about 10°F) bring about different considerations for taking care of roads than warmer winter storms, where granular salt and salt brine are cost-effective measures of melting snow and ice when used in combination with other operations (e.g., plowing). At temperatures lower than about 10°F, either extremely large quantities of salt are needed or no amount of salt can melt snow or ice pack. Chemical usage is of a widely used technique with various modifications (using deicers in daylight hours only, mixing salt with MgCl2, CaCl2, and/or agriculture by-products, and using high application rates) during extreme cold conditions. Additionally, plowing is still the ubiquitous and popular snow removal techniques in extreme cold conditions. Despite their environmental and hidden costs (air pollution, sedimentation, spring cleanup &amp; disposal), abrasives are frequently used during extreme temperatures to provide temporary traction in low traffic volume and rural roads. In spite of high cost, pavement treatments offer the benefit of reducing chemical usage and associated environmental toll, enhancing agency preparedness, and quicker recovery to bare pavement. Weather forecasting system need to be better utilized in predicting the cold weather temperatures for better preparedness. Innovative strategies continue to be tested at severe temperatures, but agencies are reluctant to use due to its higher cost especially at places of uncommon extreme cold conditions. More research needs to be done to combine innovative strategies with traditional strategies keeping cost reduction as a main factor.]]></description><pubDate>Thu, 27 Mar 2014 15:38:39 GMT</pubDate><guid>http://pubsindex.trb.org/view/1289150</guid></item><item><title>An Environmental Model for Predicting Impacts from Deicing Salts</title><link>http://pubsindex.trb.org/view/1298642</link><description><![CDATA[No abstract]]></description><pubDate>Wed, 19 Feb 2014 14:21:01 GMT</pubDate><guid>http://pubsindex.trb.org/view/1298642</guid></item></channel></rss>