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2008 Reports and Technical Summaries

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2008 Reports and Technical Summaries


Local Road Material Properties and Calibration for MnPAVE Summary Report

Final Report: 2008-56

Minnesotas M-E design program began as a Mn/DOT-funded research project at the University of Minnesota in the mid 1990s. The outcome of that research was a computer programs called ROADENT. In 2000, Mn/DOT expanded the ROADENT software into a new design program called MnPAVE. This software was calibrated using existing R-Value and Soil Factor designs, and validated using MnROAD test sections. A statewide MnPAVE training program was conducted in 2002. The current project was funded by the Local Road Research Board (LRRB) to determine material properties and model calibrations for use on local road designs.


Mileage-Based User Fee Public Opinion Study: Summary Report Phase II (Qualitative)

Final Report: 2008-55

In 2008, a series of follow up focus groups was conducted with drivers in Minnesota in order to further understand their perceptions of a mileage based user fees, especially in light of a several of major transportation events including an Interstate bridge collapse, soaring gas prices and a motor fuel tax increase. Overall, Minnesotans are much aware of the recent transportation related events because they received substantial media attention and because skyrocketing gas prices had induced some changes to driving behavior. Unlike drivers in the Phase I focus groups, it appears the recent events have impacted drivers to the degree that they are now able to make the connection between current events and the long term impacts on transportation funding. While some are able to understand and express this issue independently, others need to have the connection made for them. Regardless, participants understand the connection and agree that a decrease in the number of miles driven or reduced amounts of gas purchased will result in less revenue available from the gas tax. Some see the situation as zero sum in that they believe the impact of driving fewer miles or driving lighter, more efficient vehicles will create less damage to the roadways and, therefore, require less revenue for repair. While few had heard of a mileage based user fee concept prior to the focus groups, they understand the concept and appear to perceive it as a logical alternative which maintains the pay for use aspect of the current gas tax. Participants understanding of the concept was underscored by the types of questions raised, which attempt to understand the details of how the program might be implemented. Phase I is located at View Report


Recommended Practices for Crack Sealing HMA Pavement

Final Report: 2008-54

This report is intended to present the conclusions from LRRB 822 Tasks 1-3 in combination with several other pertinent sources including: Chapter 4 of the Best Practices Handbook on Asphalt Pavement Maintenance (2000-04), the Guidelines for Sealing and Filling Cracks in Asphalt Concrete Pavement - Best Practice by the National Guide to Sustainable Municipal Infrastructure (NRC-CNRC, 2003), and Special Provision 2331, Bituminous Pavement Crack Treatment (Mn/DOT-Revised 2/7/2008).


Overview of Rural Intersection Crashes at Candidate Intersections for the Intersection Decision Support (IDS) System

Final Report: 2008-53

The Intersection Decision Support (IDS) research project is sponsored by a consortium of states (Minnesota, California, and Virginia) and the Federal Highway Administration (FHWA), whose objective is to improve intersection safety. The Minnesota team's focus is to develop a better understanding of the causes of crashes at rural unsignalized intersections and then develop a technology solution to address the cause(s). In the original study, a review of Minnesota's rural crash records and of past research identified poor driver gap selection as a major contributing cause of rural intersection crashes. Consequently, the design of the rural IDS technology has focused on enhancing the driver's ability to successfully negotiate rural intersections by communicating information about the available gaps in the traffic stream to the driver. In order to develop an IDS technology that has the potential to be nationally deployed, the regional differences at rural intersections must first be understood. Only then can a universal solution be designed and evaluated. To achieve this goal of national consensus and deployment, the University of Minnesota and the Minnesota Department of Transportation initiated a State Pooled Fund study, in which nine states cooperated in intersection-crash research. This report provides an overview of the crash analysis phase of the pooled fund study for all participating states. This includes patterns identified in severity, driver, and type of error as well as countermeasures previously tried by states.


Review of California's Rural Intersection Crashes: Application of Methodology for Identifying Intersections for Intersection Decision Support (IDS)

Final Report: 2008-52

The Intersection Decision Support (IDS) research project is sponsored by a consortium of states (Minnesota, California, and Virginia) and the Federal Highway Administration (FHWA), whose objective is to improve intersection safety. The Minnesota team's focus is to develop a better understanding of the causes of crashes at rural unsignalized intersections and then develop a technology solution to address the cause(s). In the original study, a review of Minnesota's rural crash records and of past research identified poor driver gap selection as a major contributing cause of rural intersection crashes. Consequently, the design of the rural IDS technology has focused on enhancing the driver's ability to successfully negotiate rural intersections by communicating information about the available gaps in the traffic stream to the driver. In order to develop an IDS technology that has the potential to be nationally deployed, the regional differences at rural intersections must first be understood. Only then can a universal solution be designed and evaluated. To achieve this goal of national consensus and deployment, the University of Minnesota and the Minnesota Department of Transportation initiated a State Pooled Fund study, in which nine states are cooperating in intersection-crash research. This report documents the crash analysis phase of the pooled fund study for the State of California.


Self-Compacting Concrete for Prestressed Bridge Girders

Technical Summary: 200851TS (PDF, 275 KB, 2 pages)
Full Report: 2008-51 (PDF, 4 MB, 347 pages)

Self-compacting concrete offers significant cost benefits in precast girder construction, but performance testing and mix design standards were needed to enable use of SCC in Minnesota. Researchers evaluated wet-state performance of a range of mixes, and cast and instrumented four full-scale girders for laboratory performance testing. They also cast numerous cylinders to monitor physical characteristics and create performance models. They found SCC to be a suitable construction option.


Long Term Maintenance Effects on HMA Pavements Caused by Rumble Strips and Available Preventive Treatment Methods

Final Report: 2008-50

Rumble strips are a cost effective safety treatment for rural pavements, however they allow water to pool and increase the surface area of the pavement exposed to the elements. This research sought to address the maintenance effects of rumble strips on HMA pavements and what effect, if any, these have on the service life of the pavement. A survey was conducted which found that most respondents either noted the presence of distresses in rumble strips, or were concerned that the rumble strips were the direct cause of distresses. Next this study recommended several treatment options for pavements with rumble strips. Many of these recommendations are anecdotal and based on engineering judgment, which underscores the need for additional research. The recommended preventive maintenance treatment is to use construction funds to apply a cationic rapid set polymer modified diluted (CRS-2pd) fog seal over the entire shoulder, including the rumble strips. This will ensure an initially sealed surface and provide the maximum benefit in terms of service life extension. Crack sealing, although not an integral part of preventive maintenance for rumble strips should be applied to the adjacent cracks to slow the growth of cracks into ground in rumble strips.


Investigating the Effects on Wildlife of Reed Canarygrass Infestation of Minnesota Wetlands

Technical Summary: 200849TS (PDF, 488 KB, 2 pages)

Full Report: 2008-49 (PDF, 593 KB, 62 pages)

Habitats that contain reed canarygrass have been found to have lower diversity of traditional native plants, causing researchers to posit that the lower diversity of vegetation resulting from the invasion of reed canarygrass will have a corresponding negative effect on wildlife. While results of this study did not indicate a clear negative impact on wildlife from the invasion of reed canarygrass, researchers did note effects were more evident at lower trophic levels, negatively influencing the plant and invertebrate communities.


Improved Methodologies for the Inoculation of Prairie Legumes in Roadside/Revegetation Settings

Technical Summary: 200848TS (PDF, 761 KB, 2 pages)
Full Report: 2008-48 (PDF, 681 KB, 92 pages)

Researchers have identified that legumes and the level of nitrogen they can contribute are integral to prairie development. MnDOT includes a number of indigenous legumes in its roadside vegetation and wetland restoration plant mixes. Better inoculant delivery systems are needed to ensure that the strains being used are able to persist and function under revegetation conditions. This study recommends the use of granular soil-applied peat inoculant.


Corrosion Performance of Epoxy-Coated Reinforcement Bars

Technical Summary: 200847TS (PDF, 425 KB, 2 pages)

Full Report: 2008-47 (PDF, 10 MB, 224 pages)

High salt levels on the roadways from deicing agents can lead to serious corrosion of uncoated steel reinforcement in bridge decks. Since the 1970s, reinforcing bars have been coated with epoxy to protect them from corrosion. In this study, researchers revisit four bridges that were examined 10 years ago to evaluate the continuing performance and level of corrosion of the epoxy-coated reinforcing bars.


Evaluation of Concrete Pavement Texturing Practices in Minnesota Using the Wet Weather Accident Evaluation Criterion

Final Report: 2008-46

This project studied the effect of texturing practices on wet weather accident data in some concrete paving projects in the network of Minnesota Roads. The study responded to the requirement of Federal Highway Administration's (FHWA) Texture advisory TP 1060 of June 2005. It catalogued the various accident counts, percentage of wet weather accident and crash rates and percentage of crashes occurring in wet weather.


Report of Pavement Surface Characteristics Mini-Rodeo (M/DOT Test Data and Data Comparison)

Final Report: 2008-45

In June 2008, the Iowa State University/ Transtec Rob Rasmussen and TPF 5-(124) team were in Minnesota to do some testing on some cells at MnROAD. As Mn/DOT had only recently completed Spring OBSI and friction testing, the effort was considered as a Mini-Rodeo, few days removed. It facilitated comparison of our methods and results particularly with respect to the OBSI measurements.


Safety Effects of Centerline Rumble Strips in Minnesota

Technical Summary: 200844TS (PDF, 255 KB, 2 pages)
Full Report: 2008-44 (PDF, 1.8 MB, 111 pages)

Centerline rumble strips are a safety treatment that is gaining momentum nationally and internationally as an effective, low-cost treatment that can reduce centerline-crossing crashes. This report examines the relationship between centerline rumble strips and traffic safety on rural Minnesota roadways and makes recommendations for centerline rumble strips best practices.


Improving Carsharing and Transit Service with ITS

Technical Summary: 200843TS (PDF, 444 KB, 2 pages)
Full Report: 2008-43 (PDF, 576 KB, 80 pages)

Intelligent Transportation Systems apply technologies to solve surface transportation problems. Two ITS applications—carsharing and Advanced Transportation Information Services—could bring significant benefits to Minnesota residents by providing increased mobility and access to transit services. Researchers surveyed members of HOURCAR, a nonprofit Twin Cities carsharing organization, to gain a better understanding of CSO users in the Twin Cities. Users of Metro Transit's online trip planner were surveyed to assess how their perceptions of trust and confidence in the transit agency were affected by their use of the online trip planning service.


Environmental Effects of Deicing Salt on Water Quality in the Twin Cities Metropolitan Area

Technical Summary: 200842TS (PDF, 284 KB, 2 pages)
Full Report: 2008-42 (PDF, 3.5 MB, 88 pages)

Using salt to deice roadways in winter plays an important role in providing for the driving safety of Minnesotans. The objective of this research was to learn more about what happens to sodium chloride, the primary chemical used for deicing purposes, after the road salt has completed its job of providing safer winter roadways.


Validating Mn/DOT's Precast Composite Slab Span System

Technical Summary: 200841TS (PDF, 356 KB, 2 pages)
Full Reports: 2008-41 (PDF, 14 MB, 219 pages)

Investigators studied the effectiveness of a new design for short-span bridges, monitoring and analyzing bridges in the field and in the laboratory, paying special attention to the development of cracking in the deck above the joints of the bridge.


Best-Value Based on Performance

Final Report: 2008-40

This report discusses a Best-Value strategy for increasing the value added to a project for each dollar added. This research helps DOTs select the best contractor for a project, but the results are relevant to academics and practitioners. MnCAST, a computer software, has been developed to help implement this system.


Production and Wind Dispersal of Canada Thistle Seeds

Technical Summary: 200839TS (PDF, 404 KB, 2 pages)
Full Report: 2008-39 (PDF, 2.8 MB, 50 pages)

Researchers sought to understand the role that wind dispersal and seed production play in the spread of Canada thistle infestations. They found that wind dispersal is not as significant a factor in Canada thistle seed movement as was commonly thought.


Computation of Travel Time Data for Access to Destinations Study

Final Report: 2008-38

The goal of this project was to generate reliable travel time data using loop detector data from the Twin Cities’ freeway network collected over the past 14 years for the Access to Destinations projects.


Developing and Implementing Enhanced Pavement Marking Mangement Tools: Phase I - Mapping Tool

Technical Summary: 200837TS (PDF, 266 KB, 2 pages)
Full Report: 2008-37 (PDF, 1.8 KB, 41 pages)

MnDOT needed an application to support easy online viewing and querying pavement marking data to enable consistent, objective and cost-effective decisions regarding pavement marking needs. Phase I of this multiphase project engaged the Center for Transportation Research and Education at Iowa State University to create a mapping tool to graphically display pavement retroreflectivity data.


Generational Perspective on Teen and Older Drivers on Traffic Safety in Rural and Urban Communities

Technical Summary: 200836TS (PDF, 266 KB, 2 pages)
Full Report: 2008-36 (PDF, 3.7 MB, 94 pages)

Researchers examined the differences between the experiences and perceptions of high-risk rural and urban drivers—teens and seniors—in connection with driving purpose, crash risk, risk factors associated with crash reduction, and safety interventions. These findings will contribute to the development of effective safety intervention programs targeted to high-risk drivers.


Design Tool for Controlling Runoff and Sediment from Highway Construction

Technical Summary: 200835TS (PDF, 463 KB, 2 pages)
Full Report: 2008-35 (PDF, 4 MB, 109 pages)

Storm water runoff from construction sites can degrade the quality of waters in streams and lakes. To control runoff and create best management practices, developers enhanced a software tool that simulates the impact of highly variable weather conditions on runoff and erosion. The enhanced version factors in both on- and off-site construction variables, and improves modeling capabilities. Additional work is planned to further improve the user interface.


Perceptions of the View from the Road AIMS II: A Statewide Web Survey Aesthetic Initiative Measurement System Phase II

Final Report: 2008-34

This is Phase II of the Aesthetic Initiative Measurement System.


The Impact of Bicycling Facilities on Bicycle Commuting Levels

Technical Summary: 200833TS (PDF, 267 KB, 2 pages)
Full Report: 2008-33 (PDF, 865 KB, 39 pages)

Researchers investigated whether the presence of new bicycle facilities could be correlated with an increase in bicycle commuting rates in various U.S. cities. By mapping facilities constructed in the 1990s and analyzing changes in census data, researchers found no evidence that facilities have a stand-alone effect on bicycle commuting rates. Interviews with city bicycle coordinators revealed the influence of factors including the location of facilities, overall network connectivity and promotion efforts.


The Road to a Thoughtful Street Tree Master Plan

Full Report: 2008-32

Many if not most urban forestry successes and failures begin at the planning stage. The intent of this design manual is to replace as many of the subjective decisions made during street tree design and plant selection with objective criteria. The manual will assist communities and planners to not only select the best trees for their available planting sites, but to use specific principles of street tree design to most effectively create public green spaces, positively affect traffic patterns, and create healthy living spaces. The format of the design manual is one of prompting questions. This will not only help the user select the best plants for the area, but will pose sufficient questions to better ensure that issues of spacing, relative placement to travel corridors, and a wide variety of design elements will be satisfied. The tree species selection philosophy includes not only whether the tree is hardy enough but whether it can achieve the design function for the area. In theory, a well-placed tree in a well-designed landscape will require less maintenance and yield more rewards for the community.


Review of Nevada's Rural Intersection Crashes: Application of Methodology for Identifying Intersections for Intersection Decision Support (IDS)

Full Report: 2008-31

This is the seventh report in a series that will be used to understand the regional differences in rural intersection crashes. It documents the initial crash-analysis phase of a nine-state pooled fund study for Nevada and concludes that the best overall candidate for test deployment of the IDS vehicle surveillance system is US 50 and Sheckler Cutoff.


Review of New Hampshire's Rural Intersection Crashes: Application of Methodology for Identifying Intersections for Intersection Decision Support (IDS)

Final Report: 2008-30

Toward a Multi-State Consensus on Rural Intersection Decision Support. This is the sixth in a series of reports sponsored by a consortium of nine states and the Federal Highway Administration to improve intersection safety. To develop an Intersection Decision Support (IDS) technology that potentially can be deployed nationally, regional differences at rural intersections must be understood. To achieve this goal, the University of Minnesota and Mn/DOT conducted a State Poled Fund Study. This report documents the crash analysis phase of the Pooled Fund Study for the State of New Hampshire and concludes that the intersection that is the best overall candidate for test deployment of the IDS Vehicle System is NH 101 and HN 123.


LED Emergency Lighting for Snowplows and Other Maintenance Vehicles

Technical Summary: 200829TS (PDF, 230 KB, 2 pages)
Full Report: 2008-29 (PDF, 456 KB, 43 pages)

Researchers evaluated the safety and effectiveness of equipping MnDOT snowplows with LED-based strobe lights, which are more efficient and cost-effective than standard HID lights. Results showed that while LED lights are as conspicuous as HID for standard driving conditions and viewing angles, they are not as visible when approached from a variety of other viewing angles. Further research is needed to determine whether these angles are relevant to safety.


Design Procedure for Bituminous-Stabilized Road Surfaces for Low-Volume Roads

Technical Summary: 200828TS (PDF, 636 KB, 2 pages)
Full Report: 2008-28 (PDF, 939 KB, 70 pages)

Researchers found that bituminous stabilization of low-volume gravel roads is more cost-effective than maintaining gravel surfaces or upgrading to hot-mix asphalt, creates fewer dust problems, and increases driver safety. Investigators also developed procedures and software to make design choices easier and more reliable than decisions based on empirical estimates.


The Effectiveness and Safety of Traffic and Non-Traffic Related Messages Presented on Changeable Message Signs: Phase II

Technical Summary: 200827TS (PDF, 438 KB, 2 pages)
Full Report: 2008-27 (PDF, 469 KB, 84 pages)

Researchers evaluated how reducing the complexity and ambiguity of CMS messages would affect driver behavior and traffic flow, and learned that clarifying message content could lead to significant improvements in CMS safety and effectiveness.


Access to Destinations: Monitoring Land Use Activity Changes in the Twin Cities Metropolitan Region

Final Report: 2008-26 (PDF, 6.7 MB, 107 pages)

This report attempts to recast the process of modeling and forecasting land use change, a traditionally complex undertaking, in simpler terms. The report introduces models based on a few basic principles of land use change, and tests the models using data from the Twin Cities (years 1958 to 2005). Results of the modeling efforts indicate that none of the models presented are able to fully reproduce patterns of land use change over time. However, their simple and transparent structures are beneficial for certain sketch planning applications along with the ability to be extended rather easily and incorporate new features of urban growth processes to add complexity and realism to the models.


Traffic Volume Thresholds for Requiring Right Turn Lanes and Treatments on Two-Lane Roads

Technical Summary: 200825TS (PDF, 636 KB, 2 pages)
Full Report: 2008-25 (PDF, 3.5 MB, 194 pages)

Mn/DOT's right turn lane volume warrants were generally based on qualitative assessment rather than quantitative analysis, resulting in inconsistent application of right turn lanes and an inability to ensure cost-effective intersection design. This research project developed procedures for establishing and applying volume-based warrants that strike a balance between the cost to build a right turn lane or treatment and the money it will save in safety and operational benefits.


Determining the Impacts of Roundabouts on Roadway Networks

Technical Summary: 200824TS
Full Report: 2008-24

Roundabouts are gaining in popularity as a method for controlling traffic flow at particular intersections or portions of roadway corridors. They may, however, negatively affect overall system performance. MnDOT developed a toolbox to help cities, counties and other agencies accurately assess the impact of roundabouts on different kinds of highway systems and corridors.


Effects of Seasonal Changes on Ride Quality at MnROAD

Technical Summary: 200823TS
Full Report: 2008-23

Investigators found that frost heave, a common problem in winter weather, occurs less frequently and with less severity in thick pavements, in well-draining pavements and in those built over sand subgrades rather than clay subgrades.


Putting Research into Practice: Intelligent Compaction Implementation—Research Assessment

Technical Summary: 200822TS
Full Report: 2008-22

This project provided a qualitative assessment of MnDOT's intelligent compaction specifications and procedures, with recommendations for improving IC practices, including the use of lightweight deflectometers for quality assurance, improving equipment calibration techniques and streamlining IC data processing.


Designing a Machine for Picking Up Litter Along Minnesota Highways

Technical Summary: 200821TS
Full Report: 2008-21

Collecting trash by hand along highway shoulders and medians in the Twin Cities metropolitan area costs about $2 million per year, is time-consuming and presents serious safety hazards for MnDOT workers. Investigators designed a prototype "trash harvester" for picking up litter in grassy areas. While this prototype did not perform to MnDOT expectations and will not be commercialized at this time, it provides a starting point for further research, design and testing.


Putting Research into Practice: Best Practices Handbook for Roadside Vegetation Management 2008

Technical Summary: 200820TS

This project updated the 2000 handbook in light of recent MnDOT studies related to roadside management. The updated handbook includes a new chapter on managing roadside vegetation for wildlife and vehicle safety.


Access to Destinations: Parcel Level Land Use Data Acquisition and Analysis for Measuring Non-Auto Accessibility

Final Report: 2008-19 (PDF, 1.4 MB, 43 pages)

The goal of this Parcel Level Land Use project was to develop a detailed dataset of land use in the seven-county metro area that includes destinations influenced by all modes of transportation: auto, transit, walking, and bicycling. The resulting geographic information system (GIS) reliably represents the types of land use activities that people travel to at the neighborhood and regional levels of analysis. This dataset will serve as the second component for accessibility calculations in the Access to Destinations Initiative.


MnROAD Cell 54 - Cell Constructed With Mesabi-Select (Taconite-Overburden) Aggregate: Construction and Early Performance Report

Final Report: 2008-18 (PDF, 10.2 MB, 92 pages)

The purpose of this research was to construct and evaluate a concrete pavement made with Mesabi-Select aggregate taken from the overburden of the taconite mines in northern Minnesota. Preliminary results suggest that because taconite concrete is heavier than ordinary gravel, adequate consideration must be given to the actual build density and specific gravity of the batch. Workability-enhancing admixtures are required for best performance.


Predicting the Cost-Effectiveness of highway Median Barriers

Technical Summary: 200817TS
Full Report: 2008-17

Median barriers are an effective but costly countermeasure for cross median crashes on divided highways. Researchers developed tools MnDOT can use to identify highway sections at high risk for these crashes and predict the costs and benefits of installing cable median barrier on a given highway section.


Determination of Optimum Time for the Application of Surface Treatments to Asphalt Concrete Pavements - Phase II

Final Report: 2008-16 (PDF, 9.4 MB, 287 pages)

This report presents the results of a comprehensive effort to identify the optimum timing of surface treatment applications by providing a better understanding of the fundamental mechanisms that control the deterioration process of asphalt concrete pavements. The researchers draw a number of important conclusions from this research protecting pavements against cracking and deterioration. They also map out comprehensive recommendations for future research.


Access to Destinations: Twin Cities Metro-wide Traffic Micro-simulation Feasibility Investigation

Final Report: 2008-15 (PDF, 3.4 MB, 81 pages)

This research investigates the feasibility of developing a metro-wide traffic simulation system. The researchers looked at the state of the practice in large urban simulation projects around the world, conducted interviews with local stakeholders, and examined the capabilities of currently available simulation packages. They conclude that while a micro-simulation approach would have been the best possible solution, lack of suitable data precludes such an approach. Thus, the research team considers the hybrid mesoscopic/microscopic approach optimal. The first four in the series are numbered 2006-16, 2007-24, 2007-35 and 2008-11.


Turn Lane Lengths for Various Speed Roads and Evaluation of Determining Criteria

Full Reports: 2008-14

Researchers developed automated methods for modeling historical and prehistoric surface water features from GIS data already available to enhance the predictive accuracy of Mn/Model, a GIS-based model that predicts the potential of archaeological sites within the state of Minnesota. The research resulted in the development of the ArcGIS Toolbox Historic Water Features Tools, which create a new GIS layer of historic and prehistoric hydrologic features.


Methods to Incorporate Historic Surface Hydrology Layer in Mn/Model [Phase 4] Using Existing Geographic Information System Data

Technical Summary: 200813TS (PDF, 843 KB, 2 pages)
Final Report: 2008-13 (PDF, 5.6 MB, 56 pages)

This research was undertaken to develop methods for identifying indicators of historic and prehistoric surface hydrologic features in available Geographic Informations System (GIS) data to create a GIS layer representing relict hydrography for inclusion in Mn/DOT's MN/Model. The research resulted in an automated tool that can be used on any country in Minnesota where data input are available.


Assessing Mn/DOT's Freight Performance Measures

Technical Summary: 200812TS
Full Report: 2008-12

Researchers assessed MnDOT's current freight performance measures by identifying more general industry measures, finding available public and private sector freight information sources required for the application of these measures, assessing the cost of using these information sources, and examining the relevance of source data to MnDOT. These measures will aid long-range planning efforts for improving MnDOT's freight transportation system, including the update of the Statewide Transportation Plan.


Access to Destinations: How Close is Close Enough? Estimating Accurate Distance Decay Functions for Multiple Modes and Different Purposes

Final Report: 2008-11 (PDF, 2.5 MB, 76 pages)

The findings of the research, particularly as they relate to non-motorized modes (walking and bicycling), provide evidence that can supplement existing rules-of-thumb for pedestrian and bicyclist behavior. The findings suggest, for example, that substantial shares of pedestrian travel (perhaps one-quarter to one-third) exceed the often-cited threshold of one-quarter mile. Moreover, this finding appears to be invariant to trip purpose. Unless the segment of the population who reported these pedestrian trips are substantially different from those who either did not make utilitarian trips by the pedestrian mode or did not think to report them, this may be a welcome finding for pedestrian planning as it indicates a greater willingness to walk than is generally thought to be the case. Results for bicycle travel data reveal a substantial difference in travel distances by trip purpose. Primary activities such as work and school often involved very long bike trips (up to 20-30 KM) for those who chose this mode. In contrast, more discretionary trips (e.g. for shopping, entertainment or recreation purposes) tended to be substantially shorter in length. It would be desirable to future studies of these types of behavior to target bicycling specifically in order to provide a large enough sample to further substantiate these findings.


Pavement Evaluation Using Ground Penetrating Radar

Technical Summary: 200810TS
Full Report: 2008-10

This research developed an improved method for using ground penetrating radar data that allows users to determine pavement thickness and the presence of subsurface moisture while driving a GPR van at speeds up to 50 mph, even without having design and construction records about the pavement.


Improving Capacity Planning for Demand-Responsive Paratransit Services

Technical Summary: 200809TS
Full Report: 2008-09

Researchers analyzed archived paratransit data to create models and algorithms that can be used to help implement two approaches for improving efficiency: reoptimizing routes and selectively using nondedicated service providers such as taxis. Both measures could provide a cost savings for local transit agencies and service providers.


Developing Improved Test Rolling Methods for Roadway Embankment Construction

Technical Summary: 200808TS
Full Report: 2008-08

As part of an effort to improve test rolling equipment and specifications, investigators used models and simulations to study soil-wheel interaction, and conducted field and laboratory tests to develop theories linking wheel sinkage to soil mechanical properties.


Effects of Center-Line Rumble Strips on Non-Conventional Vehicles

Technical Summary: 200807TS
Full Reports: 2008-07

This research considered the safety impacts of centerline rumble strips on motorcyclist safety and behavior. After reviewing accident data and observing cyclist behavior on the highways and in a closed course, investigators concluded that the strips present no safety hazard to motorcyclists.


Decision Tree for Choosing the Optimal Asphalt Pavement Rehabilitation Method

Technical Summary: 200806TS
Full Report: 2008-06

Researchers developed a decision tree for choosing among three common methods of rehabilitating asphalt roads: full depth reclamation, cold-in-place recycling, and mill and overlay. The project report also describes best practices for each of these three rehabilitation techniques.


An Inventory of the Public Land Survey Records for Minnesota: The Special Instructions

Technical Summary: 200805TS
Full Report: 2008-05

Investigators located and categorized letters sent to the surveyors who ran public land survey lines and established corner monuments in Minnesota during the 1800s, describing how they should carry out their contracted work. These records, now located in archives in Iowa, Minnesota and Washington, D.C., are of great value to modern surveyors and can be digitally photographed to create a comprehensive Web-based resource.


Wet Meadow Revegetation Following Invasive Plant Control

Full Report: 2008-04

Phalaris arundinacea invades sedge meadow restorations, forming persistent monotypes that prevent community establishment. Eradicating Phalaris, however, leaves restored ecosystems prone to reinvasion. In order to restore desired plant communities, methods to control Phalaris are needed. To determine if reducing light by sowing cover crops and reducing nitrogen by incorporating soil-sawdust amendments would prevent Phalaris invasions, a study was conducted under conditions similar to a restored wetland in two experimental basins with controlled hydrology.


Investigation of Winter Pavement Tenting

Technical Summary: 200803TS
Full Report: 2008-03

Researchers studied factors that local engineers believed to cause winter pavement tenting, as well as maintenance strategies for remedying tenting. Based on a literature review, a survey of road engineers in Minnesota and field research, investigators confirmed that deicing chemicals and sands contribute to tenting, and that sealing cracks can reduce its frequency and severity.


Evaluation of Paving Fabrics for Isolation of Bituminous Cracking

Technical Summary: 200802TS
Full Report: 2008-02

Makers of pavement fabrics claim that the products can dramatically extend the service lives of overlays without requiring expensive milling and replacing. This study into the impacts of spun-glass paving fabrics in pavement sections scheduled for structural overlays found little performance benefit from these fabrics.


Compaction Remediation for Construction Sites

Technical Summary: 200801TS
Full Reports: 2008-01

Machinery passing over the right of way during highway construction results in severe soil compaction, which complicates storm water management and requires the purchase of additional land for retaining ponds. Researchers used deep tilling on a variety of soils with different plow types over two growing seasons. Deep tilling proved to be an ROW rehabilitation method.

RIC Products


Putting Research into Practice: Creating a New Bridge Information Management Tool

Technical Summary: 2008RIC08TS

Access to bridge data is essential to the effective management of the state's bridges. The Bridge Hydraulic Information database, an interactive, GIS-based application, was launched in late 2002 to allow users to display bridge hydraulic information from Trunk Highway and State Aid structures using a static database of bridge information. The new Bridge Tool, derived from this database, provides authorized users with more data about the state's bridges; displays it on maps; and generates reports from Pontis, the state's bridge management system.


Putting Research into Practice: Resource for Implementing a Street Sweeping Best Practice

Technical Summary: 2008RIC06TS
Full Report: 2008RIC06

This project synthesized recent street sweeping research to create four information sheets and a PowerPoint presentation about street sweeping best practices. These resources cover street sweeping practices, available technologies and their suitability to local needs.


Putting Research into Practice: Training Module for Pavement Rehabilitation Selection

Technical Summary: 2008RIC04TS
Full Report: 2008RIC04

This six-hour training workshop leads engineers through the process of determining a pavement rehabilitation approach. Steps include pavement assessment, survey of rehabilitation techniques and decision making.


Putting Research into Practice: Rural Road Safety Solutions Workshop Materials

Technical Summary: 2008RIC03TS
Full Report: 2008RIC03

This project developed a half-day train-the-trainer workshop and associated educational materials summarizing the latest technologies and techniques most suitable for implementing safety improvements on the local transportation system.