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As a low-cost countermeasure to rural intersection crashes, transverse rumble strips (TRS) provide an audible and tactile warning to drivers approaching an intersection with the primary goal of decreasing crashes that result from running a stop sign. The objective of this project is to evaluate the effectiveness of different TRS patterns on stopping behavior at rural stop-controlled intersections. Eight rural intersections in St. Louis County, Minnesota, were selected as test sites. Milled-in rumble strips were installed at the sites that varied in terms of number of panels (2 or 3) and number of rumble strips per panel (6 or 12). Speed, traffic volume, and video data were collected at each site before, 1 month after, and 9 months after TRS installation to evaluate various crash surrogate metrics. The most significant metrics affected by TRS configuration included percentage of vehicles engaging in a full/rolling stop at the intersection, change in average speeds on the approach near the intersection, percent of vehicles traveling 45 mph or more, and percent of vehicles engaging in late braking. A qualitative summary of the various metrics suggested that the 3-panel, 12-rumble strip design performed the best. Noise analyses were also conducted to assess whether the number of rumble strips per panel (6 or 12) affected exterior and in-vehicle noise. No significant differences in exterior noise were found, and both panels produced sufficient in-vehicle noise to alert a drowsy driver. As a result, noise was not a factor in selecting one panel type over another.

While pedestrian safety countermeasures contribute to reducing vehicle-pedestrian crashes, their impacts on winter maintenance operations are sometimes overlooked during design. There is a need to investigate the best practice guidance and solutions for the design, installation and maintenance of pedestrian safety features for year-round maintenance. To address this, we conducted a search of literature as well as agency interviews to identify and document current best practices for designing and implementing pedestrian safety countermeasures for year-round maintainability. The countermeasures reviewed included curb ramps, crosswalk markings, corner radii, curb extensions, refuge islands, and speed humps and raised crosswalks. The information collected allowed for the development of conclusions and recommendations for these features. The design dimensions and features of pedestrian curb ramps are established by the Americans with Disabilities Act and should have a slope of greater than 1:12 and a maximum cross slope of 1:50. Durable materials can be used for crosswalk markings, and these can be grooved into the pavement to provide protection from abrasion. Bulb-outs should use a 1:2 or 1:3 upstream taper and a 1:3 downstream taper. When used, tight radii of 15 feet or less should be employed. Refuge islands can range from 6 feet or greater in width, 24 feet to 40 feet in length, with a 4-foot or greater walkway width. Finally speed humps and tables should be between 3-4 inches in height, with lengths of 12-14 feet (humps concave in shape) and up to 22 feet (tables).

Various costs and benefits are incurred while performing winter maintenance operations. However, a summary of these costs and benefits for different maintenance scenarios has not been compiled to date. This report summarizes past work that documented the quantified and non-quantified costs and benefits of three different winter maintenance strategies of interest; use of abrasives, salts and other chemicals in solid and liquid forms, and snow plows. Basic strategies were defined as plowing and use of abrasives, intermediate strategies were defined as the use of rock salt and salt brine (NaCl), and advanced strategies were defined as the use of corrosion inhibitors, inhibited salt brine, magnesium chloride, calcium chloride, and blended products. These approaches employ different components, both in terms of equipment as well as materials. Some components of the various strategies have better cost and benefit information available than others. This is particularly true of sanding/abrasives and salting. Other, more recently developed and employed approaches and materials have more limited cost and benefit information published. There are also a number of different environmental impacts associated with different components of each maintenance strategy. Using information gained from the literature review, surveys, and interviews summary benefit-cost matrices were developed for various winter maintenance strategies. Information and data gap analysis has aided in identification of areas for recommended research. This document is intended for use by transportation agencies, such as by maintenance supervisors, to aid in the decision making process in terms of the selection of winter maintenance strategies used to achieve a prescribed LOS.

This toolbox was developed to provide a summary of information that local agencies should be aware of to prepare for connected and autonomous vehicles (CAVs). The main goal of this toolbox is to assist local agencies in preparing for CAVs in the short term--5 to 10 years. Since local agencies are not generally expected to have the resources to become test beds; this report provides information so that local agencies can leverage ongoing activities and resources to prepare for CAVs.

The installation and maintenance of pavement markings represents a significant financial investment for local agencies. Local agencies need a mechanism to better understand the value; cost; and need for markings along their roadways to make the best use of available budgets. This project developed a prioritization approach and spreadsheet tool (link provided in box 15) to assist local agencies in meeting this need. Multicriterion decision analysis using the simple additive weighting method was employed to assess the multiple factors/criteria that affect pavement marking decisions. An Excel spreadsheet tool was developed to implement this approach using different pavement marking alternatives; including centerlines; edgelines; centerlines and edgelines; high-visibility markings; and enhanced-durability markings. The criteria considered by the process include project type; County Roadway Safety Plan (CRSP) rating; functional classification; pavement condition; traffic volume; age of current markings; pavement width; preferences for marking costs; desired marking durability; and crash reduction potential. This tool is posted on the Local Road and Research Board (LRRB) website in the "Resources" section at the following URL: https://lrrb.org/resources/. Factor weights are used to assign a relative importance to each of these criteria for a respective alternative compared to other alternatives. The result is a performance rating score for each marking alternative relative to all model criteria and factors that provide users with information on the relative performance of different marking alternatives in comparison to one another and an estimated project cost for the highest ranking alternative for a site. The highest scoring alternative represents the marking that should be considered for use. Additionally; the tool ranks all sites being evaluated compared to one another based on the highest rating scores from each individual site.

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. Best practices for using chemicals during extremely cold winter storms include: waiting until the end of the storm, using deicers in daylight hours only, mixing salt with MgCl2, CaCl2, and/or agriculture by-products, and using high application rates. Despite their environmental and hidden costs (air pollution, sedimentation, spring cleanup & disposal), abrasives are frequently used during extreme temperatures to provide temporary traction. Best practices for using abrasives during severe cold includes prewetting with liquid deicers (although not plain salt brine-it may freeze) or hot water. Innovative strategies continue to be tested at severe temperatures, including conductive pavements and geothermal systems, which have demonstrated to be potentially effective tools.

The Pavement Marking Prioritization Tool provides a means for users to estimate the cost of pavement marking projects.

The operators and maintainers of highway networks are facing increasing demands and customer expectations regarding mobility and transportation safety during inclement weather, while confronting budget and staffing constraints and environmental challenges related to chemical and material usage. It is desirable to use the most recent advances and best practices to improve the effectiveness and efficiency of winter operations, optimize material usage, and reduce annual spending, corrosion and environmental impacts. Determining the benefits and costs of various winter maintenance practices, equipment and operations is a difficult and time consuming proposal for winter maintenance managers. This project enhanced and expanded a toolkit that was previously developed to facilitate benefit-cost analysis for winter maintenance. The toolkit items included comparing flexible blades to traditional blades, prewetting at the spreader, spreader calibration, slurries, tow plows, contracted truck (private or municipal) versus a state-owned truck, open versus closed loop spreader controls, remote cameras for monitoring remote sites locations, laser guides, and tailgate versus hopper spreaders. The toolkit is a website which receives parameter inputs from a user and generates a benefit-cost ratio for the item of interest