Researchers evaluated the low-temperature fracture properties of 12 asphalt mixtures and nine asphalt binders used in the 2008 MnROAD reconstruction project. Results will help departments of transportation choose materials that are fracture-resistant in cold weather and provide baseline data for several other low-temperature cracking research efforts.
Researchers developed a new protocol for testing the relative density in hot-mix asphalt pavement construction. The proposed procedure determines the required number of samples that should be tested based on user-specified reliability metrics. Developed for use in the lab and in the field, the new testing protocol results in more accurate payments based on contractor performance.
2009-39 In-Vehicle Technologies and Infrastructure Modifications to Prevent Crashes Along Curves and Shoulders
Researchers developed a new protocol for testing the relative density in hot-mix asphalt pavement construction. The proposed procedure determines the required number of samples that should be tested based on user-specified reliability metrics. Developed for use in the lab and in the field, the new testing protocol results in more accurate payments based on contractor performance.
2009-37 Increasing Pile Driving Efficiency for Bridge Foundations
Researchers conducted a systematic evaluation of MnDOT's pile driving formula resistance factor and investigated field and laboratory tests for predicting the magnitude and rate of pile setup. Results showed that MnDOT's pile driving formula tends to overpredict pile capacity; researchers suggest reducing its load resistance factor. Researchers also developed a new and more cost-effective dynamic formula. Setup results showed that while very few states are using field and laboratory tests to estimate setup, such methods are being investigated and show promise for application in the near future.
2009-36 Responding to the Unexpected: Development of a Dynamic Data-Drvien Model for effective Evacuation
Researchers developed an evacuation software tool for small-scale, no-notice evacuations that determines evacuee departure rates, time schedules, shortest paths and critical intersections for police officer deployment. The tool provides substantially improved network clearance times when compared to other approaches to traffic assignment.
Investigators developed software and processes for storing, manipulating and visualizing the large quantities of data produced by IC-equipped rollers so that it can be used for quality control and assurance. The software enables researchers to better understand the compaction process, to evaluate the uniformity of compaction across the entire pavement structure by identifying areas of weak and strong compaction, and to direct field personnel where to conduct quality assurance using in situ measurement devices.
2009-33 Development of Data Warehouse and Applications for Continuous Vehicle Class and Weigh-in-Motion Data
Researchers developed a data warehouse for data collected from MnDOT's continuous vehicle classification and weigh-in-motion sites that uses a standard data format. Data retrieval, statistical analysis and reporting utilities were developed to support MnDOT's data reporting needs.
2009-32 Strength and Drainage in Aggregates Mixed with Recycled Materials
Researchers compared the suitability of four recycled materials to that of virgin aggregates for use in the construction of road base and subbase layers by evaluating their hydraulic, mechanical and environmental properties. Results show that with the exception of foundry sand, recycled material mixtures were similar to virgin aggregates in drainage characteristics, stiffness, strength and environmental impact, and so are expected to be good substitutes for them as base and subbase materials in road construction.
2009-29 Bridge Health Monitoring and Inspection: A Survey of Methods
The evaluation of bridges for both safety and performance can be significantly enhanced by using remote monitoring systems to complement costly and time-consuming hands-on inspections. Researchers surveyed the many technologies and methods available for remotely monitoring bridges and developed a database tool to aid bridge engineers in deciding which commercially available products best fit a particular application.
2009-28 Putting Research into Practice: Reducing the Costs of Noxious Weed Management
Researchers set out to verify the key findings of Phase I of this implementation, which compared the efficiencies of two weed surveying methods using different segment lengths. Results confirmed Phase I findings showing that while taking less effort to conduct, the use of 14-foot segments was less precise than the use of 225-foot surveys, and too imprecise to be used to quantify infestation density.
2009-27 Using Fly Ash to Improve Recycled Pavement Foundations
Researchers evaluated the strength, stiffness and performance of fly ash-stabilized recycled pavement materials both in the laboratory and in the field, and found that their resilient modulus increased significantly with fly ash content and remained stable even over numerous freeze-thaw cycles. They used these results to create design procedures establishing a gravel equivalency to Class 5 base course. Researchers also evaluated the environmental impacts of these materials and found that groundwater concentrations of leachates would be expected to meet environmental standards.
2009-25 Preventive Maintenance for Recreational Trails
Researchers evaluated the effectiveness of using pavement preventive maintenance techniques for recreational trails—including various surface sealing and crack treatments—by applying them to several trails in Minnesota and comparing their permeability and surface texture to untreated control sections. Results showed that all of the treatments reduced the permeability, and all fog seal treatments did so while consistently providing a high-quality surface for trail users.
2009-24 Access to Destinations: Application of Accessibility Measures for Non-Auto Travel Modes
Using measures of time and distance and highly detailed land use data, researchers developed reliable accessibility measures for transit, walking and cycling in the Twin Cities metropolitan area for three time periods (1995, 2000 and 2005). A study area in south Minneapolis is used to demonstrate proof of concept for the project.
2009-23 Integrating Platoon-Priority Signal Control with Advance Warning Flashers
Investigators developed an integrated signal control system that uses platoon priority and advanced warning flashers to increase the efficiency of high-speed isolated intersections. Simulations on data collected at a high-speed intersection found that the new system reduced delays and stops on the major approach by more than 50 percent, with an overall reduction in intersection delays and stops of 20 percent.
2009-21 Mechanistic Modeling of Tests of Unbound Granular Materials
Researchers made progress toward developing a mathematical model that provides a physics-based, mechanistic correlation between the California bearing ratio, resilient modulus and dynamic cone penetrometer tests. To accomplish this objective, researchers investigated and modeled relationships between the basic material properties of unbound aggregates, including the interaction of individual particles.
2009-20 Cost Analysis of Fish-Friendly Culvert Designs
Traditional culvert designs can interfere with the natural passage of fish and other aquatic life. In this study, researchers evaluated four alternative fish-friendly culvert designs and performed a cost analysis comparing their costs with traditional culvert project costs.
2009-18 Preventive Maintenance Best Practices for HMA Pavements
Researchers evaluated the effectiveness of pavement management crack and surface treatments, and created a manual to provide agencies with guidance on the use of these treatments as part of a long-term strategy for preserving and improving the condition of road networks. One project recommendation was that Superpave pavements still require preventive maintenance.
2009-17 Subsurface Drainage Manual for Minnesota Pavements
Investigators compiled best practices for selecting, designing, constructing and maintaining subsurface drainage structures for pavement types and situations commonly found in Minnesota.
2009-16 Impacts of Upgrading Roads on Local Property Values
Researchers used case studies to quantify the benefits of road improvements reflected in local property values. The empirical analysis method used in this study yielded mixed results, suggesting the need for improved methods and more robust data sets to analyze the effects of transportation improvements on property values.
2009-15 Best Practices for RAP Use Based on Field Performance
Researchers examined whether asphalt pavements containing recycled asphalt pavement in the wear course are prone to early failures. They conducted a survey of county engineers and tested samples from selected projects for dynamic modulus and other properties. Results showed that field performance of pavements depended more on the low-temperature performance grade of binders and the stiffness of underlying layers than on the percentage of RAP in the wear course mixture.
2009-14
Putting Research into Practice: Intelligent Compaction Performance-Based Specifications in Minnesota
Investigators developed procedures for implementing intelligent compaction and light weight deflectometer equipment. The project also developed four IC specification options and involved a series of five training seminars for MnDOT staff and contractors.
2009-13 Crack and Concrete Bridge Deck Sealant Performance
Researchers synthesized best practices and product recommendations for concrete bridge deck crack sealants from published research, the performance of various solutions and a survey of state DOTs regarding their current practices.
2009-12 Putting Research into Practice: Using the DCP and LWD for Construction Quality Assurance
Investigators developed model specifications and test procedures for using dynamic cone penetrometers and light weight deflectometers during road construction to ensure adequately stiff subgrade, granular fill, subbase and base materials.
2009-11 Post-Construction Evaluation of Traffic Forecast Accuracy
Accurate traffic forecasting is essential for planning transportation projects that will fit future traffic demands. This study compared forecasts to actual post-construction traffic for projects in the Twin Cities metro area to determine forecast accuracy and to identify factors affecting accuracy.
2009-10 Putting Research into Practice: Refining Noxious Weed Management
This project evaluated the relative efficiencies of two sampling plans for measuring weed infestations in highway rights-of-way. Results, while not conclusive, suggest that while 14-foot population distribution surveys require less time to conduct, they were less precise than 225-foot population density surveys at quantifying infestation.
2009-09 Recycled Pavements Using Foamed Asphalt in Minnesota
Investigators gathered and recorded information about the best practices, construction techniques, mix design, specifications and performance of foamed asphalt recycled pavement, and used this information to develop preliminary design guidelines and specifications for the use of foamed asphalt in Minnesota. An evaluation of existing Minnesota projects showed that pavement layers recycled using foamed asphalt develop a uniform strength, and that the foamed asphalt formed a cohesive matrix when mixed with reclaimed material.
Researchers compared the performance of conventional edge drain systems to centerline drainage systems to determine if centerline drainage is a viable alternative to edge drains. The study does not recommend centerline drainage except at the occasional site in which water may rise from below the subgrade into the pavement structure.
2009-07 Best Practices for Advanced Acquisition of Right of Way
Acquiring right of way can be the most expensive part of many transportation projects. Advanced acquisition—purchasing ROW before project design approval—has been used in an effort to decrease costs and expedite project completion. Researchers examined current MnDOT ROW practices, identified the types of properties that offer the greatest financial benefit when employing advanced acquisition, and recommended the development of guidelines to increase awareness and standardize application of ROW preservation tools.
2009-06 Putting Research into Practice: Calibrating the MEPDG for Minnesota
Investigators calibrated the 2002 Mechanistic-Empirical Pavement Design Guide Manual of Practice for Minnesota conditions by developing input parameters, conducting a sensitivity analysis, and comparing MEPDG predictions to those of MnPAVE and the current design standard. Results helped debug the MEPDG software and reduce its bias and error in design predictions for both rigid and flexible pavements.
2009-05 The Effect of RAP on the Structural Capacity of Pavement Base Layers
Researchers evaluated the effects of freeze-thaw cycles and severe moisture conditions on the stiffness and strength of RAP pavement base layers by evaluating RAP and virgin aggregate samples for resilient modulus, shear strength and other properties from several road construction projects. Results showed that RAP had a higher resilient modulus and equivalent shear strength to virgin aggregate, was negligibly affected by freeze-thaw and is a viable alternative to virgin aggregates for use in road base layers.
2009-04 Best Practices for Dust Control on Gravel Roads
Road dust from increased traffic on aggregate-surfaced roads results in complaints from roadside residents, impaired driver vision, and potential hazards for drivers on narrow roads and at intersections. In this study, researchers evaluated three dust control products and determined a maximally effective application schedule for dust control treatments.
2009-03 Evaluating Active and Passive Crosswalk Warnings at Unsignalized Intersections and Mid-Block Sites
Researchers compared the safety effects of passive warnings (roadway markings accompanied by warning signs facing oncoming traffic) and active warnings (passive warnings accompanied by a flashing light that is either continuously flashing or activated by someone wishing to use the crosswalk) at crosswalks at unsignalized intersections or mid-block sites. The study found no significant differences between passive warnings and active warnings in encouraging more cautious behavior in motorists approaching the crosswalk and suggests the need for further research.
2009-02 Assessing the Environmental Impact of Tire Shreds Used Below the Water Table in Road Base Fills
Researchers evaluated the environmental effects of chemicals leached from tire shreds placed below the groundwater table for use as a lightweight fill in wet road bases. They found an increase in surface and groundwater concentrations of various chemicals; metals; and four tire-relevant semivolatile organic compounds, which had a toxic effect on some aquatic organisms.
2009-01 Real-Time Arterial Performance Monitoring Using Traffic Data from Existing Signal Systems
Researchers developed the SMART-SIGNAL (Systematic Monitoring of Arterial Road Traffic Signals) system to collect and archive high-resolution traffic signal data and automatically generate real-time performance measures such as travel time, queue length and intersection delay. Engineers can use this data to set timing schedules for individual traffic signals.
2009RIC12 Stormwater Maintenance Best Management Practices Resource Guide
Investigators assembled a guide that provides definitions and descriptions of the five stormwater management systems most commonly used in Minnesota. The guide offers inspection and maintenance templates for adaptation by local engineers to specific facilities and procedures.
2009RIC11 Putting Research into Practice: Implementing Pavement Management in Minnesota
Investigators surveyed Minnesota's cities and counties and pavement management system vendors to develop a resource guide for local agencies interested in implementing a pavement management system. The guide includes a matrix that compares the features and functionality of pavement management systems used in Minnesota as well as Minnesota case studies that offer implementation tips and benefits identified by users.
2009RIC08 Putting Research into Practice: Snowplow Calibration Guides for Mn/DOT and Local Governments
Investigators used the expertise of vendors and winter operations professionals from across Minnesota to create calibration guides that address the most common types of snowplow sander controllers used by cities and counties in Minnesota and by Mn/DOT districts. The guides include step-by-step calibration instructions, one-page quick sheets for staff more experienced with calibration, instructions for weighing material for sander calibration and other calibration aids.
2009RIC02 Putting Research into Practice: Innovative Contracting Resources for Local Governments
Investigators developed guidance for local governments to make effective use of traditional and innovative contracting methods on the transportation projects they manage. Innovative contracting practices presented in the report include best value, force account, bidder qualification and alternate bidding.
