This project implements research that classifies steel bridges based on the frequency and severity of fracture and fatigue-sensitive details that are present in each bridge. The gross ranking of bridges with high, medium or low need for preventive maintenance or special inspection will be stored in Pontis, MnDOT's bridge management database, for use by bridge inspectors and those responsible for managing Minnesota's bridges.
2007-51 Improving Minneapolis/St. Paul's Ramp Metering System for Smoother Traffic Flow
To streamline traffic flow and reduce backups on Twin Cities highways, MnDOT engineers researched ways to improve the algorithm they use to estimate queue size on entrance ramps and calculate minimum rates for releasing cars from ramps to highways. More than 20 parameters were tested through computer simulations. The new optimized algorithm and ramp-monitoring system increases average speed and reduces travel time and energy consumption.
2007-49 Developing a Computer Program to Select Peak Dynamic Sensor Responses from Pavement Testing
In order to better analyze the vast amounts of pavement response data that Mn/DOT collects, investigators updated and enhanced MnDOT's Peak-Pick software program. The updated version is more robust and efficient, and provides multiple ways to analyze the data.
2007-47 Shear Capacity of Prestressed Concrete Bridge Girders
Design specifications of shear reinforcement requirements in prestressed concrete bridges have changed significantly. Researchers load-tested to failure a girder that was built to older design codes and evaluated its shear capacity. They also examined how to judge the shear capacity of other bridges designed to older specifications.
2007-46 Performance Assessment of Underground Stormwater Treatment Devices
Researchers developed a universal method for evaluating the performance of underground stormwater treatment devices in retaining sediment for removal after a storm event. The method was the first of its kind and was endorsed by ASTM.
2007-45 Development of a PC-Based Eight-Channel Weigh-in-Motion System
Researchers developed technology for a WIM system that can be easily built, can record vehicle weight across four lanes of traffic and does not need to use actual vehicles to calibrate. The system is much less expensive and easier to modify than a proprietary system.
2007-44 Using Intelligent Transportation Systems Data to Improve Transit Performance and Management
Researchers analyzed the data collected by automatic vehicle location and automatic passenger counter systems on a Metro Transit bus route to understand and address its service reliability issues, developing a study methodology that can be applied to improve additional routes.
2007-43 Investigation of Low-Temperature Cracking in Asphalt Pavements
In the cold climates of the northern United States, asphalt pavements are susceptible to low-temperature cracking. This study identified simple laboratory tests for predicting the fracture resistance of asphalt mixtures, procedures that were found to correspond to field performance.
2007-42 Surveying Noxious Weeds in Roadway Rights-of-Way
Mn/DOT District 4 staff used a new sampling procedure to locate and measure infestations of noxious weeds and concluded that examining a greater number of much smaller areas, selected with regard to ecozone, was more accurate and would allow for better targeting of weed control resources.
2007-41 Rural and Urban Safety Cultures: Human-Centered Interventions Toward Zero Deaths in Rural Minnesota
To help Mn/DOT shape safety interventions, rural and urban respondents answered survey questions about driving risks and behaviors. A small group then underwent driver testing in simulated urban and rural environments. Rural drivers were found to have lower perceptions of driving risk, and the rural environment appears to encourage unsafe speed choices and intersection crossing behavior, particularly among teen drivers.
2007-39 Minnesota's Transportation Research Site Database
During a five-year project, researchers created and populated a database of the many roadway test sections created for research projects across Minnesota over the last several decades. This maximizes test section investments by putting original test data as well as more recent observations of test sites within the reach of city, county and state engineers.
Researchers investigated the effectiveness of the recently discovered biological control agent PST for the control of Canada thistle in roadside rights-of-way and prairie wetland restoration systems, and found that an integrated management system based on PST has a significant impact on the management of this weed.
2007-37 Using Real-Time Road Condition Measurements for Automated Winter Road Maintenance
Researchers developed and tested a first-of-its-kind measurement system that, when mounted on snowplows, produces real-time measurements of the tire-road friction coefficient. These measurements are used to automatically adjust the application of deicing chemicals, which allows deicing materials to be used more efficiently and reduces environmental damage from chemical runoff.
2007-36 Can Cone Penetration Testing Measure the Resilient Modulus of Soils?
Researchers evaluated the feasibility of using Cone Penetration Testing data to estimate resilient modulus in the field and to identify organic soils. Results show that while the statistical analysis model used by researchers was not sufficient to evaluate resilient modulus or organic soil content, this study provides groundwork for enhancing this model to further the use of CPT in the field.
2007-25 Measuring the Material Properties of Aggregate Base Containing Recycled Materials
Researchers performed both field and laboratory measurements of resilient modulus for three reconstructed roads that used recycled asphalt paving material in the pavement base, and also performed modulus, shear strength and deformation tests on reclaimed aggregate base and recycled asphalt mixed at various ratios. This established procedures and generated necessary inputs for Mn/DOT's pavement design manual.
2007-22 Incorporation of Fatigue Detail Classification of Steel Bridges into the Mn/DOT Database
This project produced a framework for enumerating and ranking bridge details that are prone to fracture and fatigue. Such a ranking system will assist in targeting funds and resources to the most vulnerable bridges and in evaluating requests for load limit increases.
2007-15 Commuter Bicyclist Behavior and Facility Disruption
Researchers tracked bicycle commuters' behavior using small Global Positioning System receivers enhanced by a wide-area augmentation system to better understand how infrastructure improvements and disruptions impact cyclists. Small GPS units offer an accurate and affordable method for tracking commuter behavior and will provide transportation planners with data to help prioritize infrastructure improvements.
Methods to Select the Lowest Cost Alternative
Researchers performed an economic analysis to identify the most cost-effective maintenance strategies for a large group of aging concrete bridge decks. Based on current prices, researchers determined that repair is preferable to redecking if repair can elevate a deteriorated deck to an acceptable condition. Researchers also developed least-cost repair/replacement strategies for all of the decks in the group.
2007-12 Demonstration of Ash Utilization in Low Volume Roads
Coal fly ash was used to stabilize reclaimed pavement materials in two Minnesota construction projects to demonstrate the viability of this practice. The ash-treated materials displayed improved stiffness, and analysis of leached moisture did not reveal unsafe trace element levels.
2007-11 Pavement Design Using Unsaturated Soil Technology
A new method of using the principles of unsaturated soil mechanics during pavement design was developed. This will allow pavement engineers to better take into account field conditions and seasonal variations in moisture content. The new models developed in this study allow pavement designers to estimate the stiffness and strength of any soil encountered in the field.
2007-10 Field Validation of Intelligent Compaction
Researchers evaluated intelligent compaction monitoring technology used in earthwork construction for quality control and assurance. They found that while IC technology is a feasible alternative for quality control and potentially quality acceptance, some challenges remain in validating IC rollers to accurately interpret their measurements.
2007-09 Implementing the International Roughness Index for Concrete Pavement Evaluation
Mn/DOT was trying to improve its method for awarding bonuses to contractors for especially smooth concrete pavement. Investigators compared the old method for measuring smoothness to the new International Roughness Index standard, looking at how each pavement analysis method depicts various surface imperfections and evaluating the different options for implementing IRI incentives.
2007-08 Improving the Strength and Stability of Prestressed Concrete Through-Girder Pedestrian Bridges
Because of a growing concern about the overall safety of pedestrian bridges, investigators used laboratory studies and computer simulation to gauge their ductility, strength and stability as compared with AASHTO specifications. Results showed that several modifications to AASHTO bridge specifications will make future pedestrian bridges stronger and more resistant to collapse.
2007-04 The Safety of Pedestrian and Bicycle Travel in Minnesota: Inventory, Analysis and Prospectus
Researchers scanned the available sources of accident data involving bicycles and pedestrians for trends such as correlations between accidents and neighborhood attributes. They examined current accident data collection and made recommendations to increase the quantity, quality and use of bicycle and pedestrian crash data.
Measuring the Safety Effects of Signal Installation and Left-Turn Phasing Schemes
Researchers analyzed before-and-after crash data, and used statistical analysis and computer modeling to measure the safety effectiveness of Mn/DOT's practices for signal installations and left-turn signal phasing schemes at highway intersections. The research findings were roughly consistent with Mn/DOT's guidance and practice in these areas; analysis should be repeated in several years when more after-treatment data are available.
2007-02 Factors Affecting Commute Times in the 1990s
The average length of time it took Minnesota workers to commute to work increased about 2.5 minutes during the 1990s, a larger-than-normal increase. Unidentified factors other than urban sprawl and traffic congestion were thought to be creating a significant shift in commuter behavior. A detailed statistical analysis showed little correlation between economic factors and commute times, and that some of the increase was due to a change in methodology in the 2000 census.
2007RIC09 Putting Research into Practice: Updating Minnesota's Crash Mapping Analysis Tool
The Minnesota Crash Mapping Analysis Tool is a geographic information system-based mapping tool used by Minnesota city and county engineers and other traffic safety professionals to analyze crash data and produce maps, charts and reports of selected crash data. The objective of this project was to augment MnCMAT with current and additional historical crash data, and implement a series of updates that enhance the user interface to better meet user needs.
PP07GEo Putting Research into Practice: Training Module for Designing and Constructing with Geosynthetics
A geosynthetics expert leveraged decades of Mn/DOT research and federal guidance to create a one-day seminar that described the range of geosynthetics applications occurring throughout Minnesota, such as pavement reinforcement and pavement layer separation, and presented guidelines for materials, design, installation and inspection for each use.