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Transportation Research Syntheses (TRS)


TRS Overview

What is a TRS?

A Transportation Research Synthesis (TRS) is a short-turnaround research report that addresses a specific research topic. TRSs include summaries of completed and in-progress research, or reports about the state of the practice among departments of transportation (DOTs).

A TRS goes beyond the scope of literature searches; it can include interviews or surveys, and the resources found are clearly organized and summarized — with contact names, web links and other specifications.

To learn more about our TRS program can help you, download our TRS program flyer (PDF).

Alternatives to Seal Coats


(PDF, 0.3 MB, 44 pages)

Seal coats are one of many techniques commonly used for asphalt pavement preservation and chip seals are the most commonly used in Minnesota. In some applications, chip seals are not the best surface treatment alternative, such as in areas with frequent or high stress turning movements like cul-de-sacs or intersections, and can suffer chip loss and/or bleeding. The purpose of this Transportation Research Synthesis (TRS) was to summarize current seal coat practices and identify alternatives that provide pavement protection, extend pavement life similar to chip seals, and avoid the identified problems. Other surface treatment techniques used around the country include fog seals, bio seals, sand seals, sandwich seals, slurry seals, and micro surfacing and include many proprietary or brand name products.

Mitigating Frost Heaves and Dips Near Centerline Culverts


(PDF, 0.5 MB, 16 pages)

Minnesota county engineers have sometimes observed heaves and dips near centerline culverts during cold winter months. In these instances, during the late winter and early spring, the area where a culvert has been replaced does not heave or heaves only slightly, while the roadway on either side of the replaced culvert heaves. The heave and dip disappear entirely, or nearly entirely, during the late spring and early summer when the road embankment thaws. This Transportation Research Synthesis includes a review of literature and results of a survey of transportation agencies in cold-climate states in the United States and provinces in Canada that may have experience with heaves and dips near centerline culverts during cold weather, and practices to mitigate them.

Large Corrugated Metal Pipe Repair Techniques: A Survey of Practice and Related Resources


(PDF, 1.9 MB, 47 pages)

Much of the research-oriented literature on rehabilitation methods for corrugated metal pipe culverts is focused on smaller-diameter pipes. MnDOT is interested in learning more about the effective practices and costs to structurally rehabilitate bridge-size large‐diameter (10 feet or greater) CMP. Of particular interest are current practices for extending the life of a deteriorating CMP by performing a repair or rehabilitation that provides continued structural support for traffic. This Transportation Research Synthesis uses a literature review and a survey of cold-weather states to gather information about repair techniques, potential environmental concerns, structural issues to consider before and after repair, and the life-cycle cost-effectiveness of various repair techniques used for large-diameter CMP.

Quantifying the Impact of Bridge Maintenance Activities on Deterioration: A Survey of Practice and Related Resources


(PDF, 2.6 MB, 81 pages)

Bridge maintenance treatments are expected to have an impact on remaining service life and bridge life-cycle costs. MnDOT is interested in learning about other transportation agencies’ practices to quantify the benefits of bridge maintenance treatments and how those treatments are incorporated into an agency’s deterioration model. This Transportation Research Synthesis uses a literature review and a survey of domestic and international transportation agencies to gather information about the use of various bridge maintenance treatments, efforts to quantify the benefits of bridge maintenance treatments, and the use of deterioration models in examining the impact of bridge maintenance.

State of the Practice for Managing, Maintaining and Operating Culverts: A Review of Deterioration Curves and Tools


(PDF, 501 KB, 25 pages)

When estimating the service lives of culverts, MnDOT generally relies on predictions of the durability of the pipe materials with which culverts are constructed. However, because of varying environmental conditions and other factors, this method is not always accurate. MnDOT is looking for other factors that affect the service lives of culverts under 10 feet in diameter and how they can be incorporated into mathematical models of their deterioration. The agency would also like to better quantify the effects of repairs. This Transportation Research Synthesis includes a literature review on the state of the practice for managing, maintaining and operating culverts, in particular the effects of maintenance activities on culvert deterioration; and results of phone interviews with representatives at state departments of transportation concerning their methods for tracking culvert deterioration. Results show that most states do not use deterioration models for culverts and have not quantified the effects of maintenance on culvert service life.

Appendices (.zip)
Appendix B.3 (zip)

Managing Ancillary Pavements: A Survey of Practice and Related Resources


(PDF, 5.9 MB, 170 pages)

Practices for managing the ancillary pavements that are not part of the main roadway, such as shoulders, ramps, turn lanes and frontage roads, do not appear to be as widely documented as the practices for managing mainline pavements and bridges. MnDOT is interested in learning how other transportation agencies inventory and track the condition of ancillary pavements, what measures and targets they use to track agency performance in managing these assets, and how these pavements are addressed in programming and investment decisions. A literature search conducted for this Transportation Research Synthesis netted relatively little documentary evidence of transportation agency practices to manage ancillary pavements, while a survey of transportation agencies provided significant detail about agency practices for managing these pavement classes.

Work Zone Intrusion Reporting: A Survey of State


(PDF, 2 MB, 14 pages)

Work zone intrusions—when traveling vehicles enter the work space of a work zone—are a clear safety concern even if they do not result in an accident, and they may indicate locations where future accidents are likely. MnDOT is interested in learning how other state DOTs collect work zone intrusion data, both in terms of the technology they use for data collection and the specific information they collect. This Transportation Research Synthesis surveyed state DOTs and conducted follow-up interviews with states that collect work zone intrusion data. The relatively small number of states that do collect intrusion data typically do so via paper or electronic form.

Future Impact on Minnesota Transportation Revenue Collection of Commercial Fleet Conversion from Diesel Fuel to Natural Gas


(PDF, 2 MB, 14 pages)

Natural gas has the potential to be increasingly used as a motor vehicle fuel, particularly for trucks, in the future. Since the fuel tax makes up nearly half of Minnesota's Highway User Tax Distribution Fund, MnDOT is concerned about the potential impact of natural gas on future fuel tax receipts. This TRS includes a review of literature and current policies, as well as interviews with practitioners in nearby states and in the natural gas industry, to evaluate the likely impact of natural gas conversion. The report concludes that the near-term impact of natural gas conversion on Minnesota fuel tax receipts is likely to be relatively small, in part because the state currently taxes both liquefied natural gas and compressed natural gas at nearly the same rates as gasoline or diesel fuel on an energy equivalent basis.

Summer Maintenance Operations Reporting: A Survey of State and National Practice


(PDF, 29 MB, 593 pages)

MnDOT is interested in learning about the publications prepared by other state departments of transportation that provide quantitative and qualitative information about an agency’s summer maintenance performance. This Transportation Research Synthesis presents the results of a survey of state DOTs and a literature review that examined reporting produced by state DOTs to assess an agency’s maintenance performance, specifically the performance of summer maintenance activities. Among the topics addressed in this research are the types of maintenance activities monitored, data management, target audiences and reporting practices. Sample reporting from state DOTs is also reviewed.

Benefits and Costs of Increasing Truck Load Limits: A Literature Review


(PDF, 5.4 MB, 25 pages)

When lawmakers raise the legal weight limits for heavy trucks, local highway agencies must address the impacts of heavier vehicles on their roadways. The Local Road Research Board is examining the advantages and disadvantages of increased weight limits, and investigating how counties and cities in Minnesota can prepare for the impacts of future weight limit increases at the federal or state level. This Transportation Research Synthesis reviews recent research on infrastructure impacts, traffic and safety impacts, roadway design considerations, environmental impacts, and other considerations, with an emphasis on the effects on local highways. The report includes a map of neighboring states’ weight limits.

Coordination Between State Transportation Agencies in Multi-State Metropolitan Planning Areas: A Survey of State Practice


(PDF, 14.0 MB, 194 pages)

With the passage of MAP-21 and the increased emphasis on performance-based planning, greater coordination is expected between state departments of transportation when a metropolitan planning organization’s metropolitan planning area covers more than one state. This Transportation Research Synthesis used a survey of a select group of state DOTs to gather information about how those states address multi-state MPO oversight. Survey respondents provided sample agreements that define participants’ roles, and addressed the distribution of federal funds, best practices and any areas of concern identified when coordinating multi-state MPO activities.

Monitoring Motor Vehicle Driver Fatigue


(PDF, 1.3 MB, 21 pages)

MnDOT staff are required to complete a wide range of driving tasks, and MnDOT is interested in determining how fatigue affects an individual’s ability to drive safely. To better understand the relationship between fatigue and unsafe driving, MnDOT would like to learn more about the methods, tools and technologies used to predict, diagnose and monitor driver fatigue. To meet this need, CTC & Associates conducted a review of recently published research and supporting documents that examine the characteristics of driver fatigue and how to predict and monitor it.

Appendix A (PDF, 0.5 MB, 33 pages)
Appendix B (PDF, 5.9 MB, 68 pages)

New Approaches for Roundabout Lighting to Enhance Pedestrian Safety


(PDF, 0.5 MB, 20 pages)

As the number of roundabouts in Minnesota continues to grow, local road authorities are interested in new approaches to roundabout lighting to enhance pedestrian safety while reducing ongoing energy costs. One emerging approach is ecoluminance, a lighting concept that incorporates light reflected from plants, low-height bollard-based lighting, and retroreflective elements to light roundabouts while reducing power consumption. The Local Road Research Board was interested in more information about this and other approaches to lighting roundabouts effectively but efficiently to improve pedestrian safety, and more generally in a synthesis of information that could serve as a starting point for review of several topics in roundabout lighting.

To gather this information, the authors conducted a literature search to identify design guidance, research and best practices. We also conducted interviews with researchers and practitioners who have extensive experience in this area.

Strategic Plans for Transportation Research Programs: A Survey of State and National Practice


(PDF, 2.5 MB, 93 pages)

MnDOT is embarking on a strategic planning effort for research across the agency and is interested in knowing more about the effective elements of other state and national transportation research program strategic plans. Of particular interest are steps taken to measure the effectiveness of meeting strategic program goals.

Twenty-two state or district departments of transportation (DOTs) responded to a survey. Half of the respondents provided a plan or indicated that a plan was in process; the other half of the respondents reported that they have no plan or have suspended update of an existing research strategic plan.

PowerPoint presentation (PDF, 3.2 MB, 30 pages)

Chloride Free Snow and Ice Control Material


(PDF, 0.5 MB, 42 pages)

Rock salt is the most common deicer used for winter maintenance in Minnesota. It is affordable to purchase, and is usually an effective winter maintenance tool, but it causes damage to lakes, rivers and groundwater. The Local Road Research Board (LRRB) funded this review of areas within winter maintenance that might lead to lower salt (chloride) use.

State of Practice for Defining, Demonstrating and Documenting Transportation Efficiencies


(PDF, 4 MB, 98 pages)

Public transportation agencies often have an interest in demonstrating efficiencies in the capital development, maintenance and operations of transportation systems. This Transportation Research Synthesis examines how transportation agencies define, demonstrate and document efficiencies.

Pavement Preservation Resource Centers


(PDF, 0.2 MB, 22 pages)

Although MnDOT was involved with the initial development (and provides a link to) Pavement Interactive, the Local Road Research Board (LRRB) conducted this study to understand the needs of a pavement preservation resource center by Minnesota local agencies. The two main goals were: to understand if there is a need for a pavement preservation resource center in Minnesota and if so, what type (online resource, staffed center, virtual center, etc.); and investigate what pavement preservation resource centers are available across the nation along with detailed information on how they were established, funded and how they currently operate.

Software Programs and Processes for Tracking Capital Program Funds


(PDF, 1.4 MB, 55 pages)

This State of Practice Transportation Research Synthesis (TRS) examines software programs and processes used by State DOTs to track capital program funding. It also summarizes relevant practices of selected non-DOT entities. This research included surveying State DOTs and compiling results, documenting software programs used by non-DOT agencies, and summarizing four featured State DOT examples as selected by MnDOT.

Gravel Road Management Tools


(PDF, 0.4 MB, 60 pages)

The Local Road Research Board (LRRB) conducted this study to understand the gravel road management needs of Minnesota local agencies. The two main goals were to determine the needs of local agencies and identify what gravel road management tools are currently used/available. This report includes a summary of local and national survey findings, a matrix of existing gravel road management tools and an appendix with detailed survey results and interview summaries with software vendors.

Right and Left Turn Lane Warrants


(PDF, 2.9 MB, 46 pages)

This TRS addresses a perceived lack of guidance relative to the installation of right and left turn lanes along local road systems. A literature review was conducted to determine what existing turn lane guidance is available and being used by different agencies. The review focused on six key areas that local agencies are concerned with and encounter when deploying turn lanes on their road systems and include both long-term and short-term scenarios.

Writing Literature Reviews for Transportation Research Projects


(PDF, 1 MB, 14 pages)

The literature review is an important part of research, but researchers often treat it as an afterthought. This research examines the various functions of a literature review and the formats and organizational methods that help the literature review perform those functions. It also includes guidelines for producing a literature review, examples of effective transportation-related literature reviews and draft specification language.

Transportation Agency Practices Currently Employed for Bridge Maintenance Painting Operations: Findings from a National Survey


(PDF, 2 MB, 71 pages)

Determining the extent of coating deterioration and prioritizing maintenance painting projects statewide can be a daunting task, particularly in states with more severe or dynamic climates. This research investigates steel bridge maintenance painting practices of transportation agencies throughout the United States in order to identify best practices for the development of a statewide bridge maintenance painting program.

Joma Snowplow Blade Life Span: A Survey of State Experience


(PDF, 653 KB, 38 pages)

Joma snowplow blades, which consist of carbide inserts brazed into steel segments that are encased in rubber, are widely used in Minnesota. Recently, MnDOT has noticed premature wearing of new Joma blades relative to those purchased a few years ago. This research surveys winter maintenance professionals in Minnesota and other states to determine how widespread this issue appears to be and what factors may be contributing to it.

Best Practices in Pavement Design for Design-Build Projects


(PDF, 710 KB, 31 pages)

MnDOT has been using design-build contracting on certain transportation construction projects for several years. Design-build has not been used on pavement construction, but MnDOT is interested in expanding its design-build program to include pavement in the near future. Through a survey of other states’ design-build managers and follow-up interviews with selected respondents, this research synthesizes best practices in the use of design-build contracting in transportation projects that include a pavement design component.

Airspace Protection and Land Use Zoning: A Nationwide Review of State Statutes


(PDF, 5 MB, 194 pages)

Airport zoning generally falls into two categories: height limitation zoning and land use zoning. Most states empower local governments to adopt and enforce airport zoning ordinances, and some states require it. MnDOT is analyzing Minnesota’s existing statutes and rules regarding airport safety zoning to determine whether updates are needed. MnDOT is especially interested in identifying how other states approach the issue of requiring local governments to enact land use zoning. This synthesis serves as a step toward identifying other states’ approaches to airport zoning and will help inform future updates to Minnesota statutes and rules.

STIP and TIP Amendment Procedures: A Review of State and MPO Practices


(PDF, 566 KB, 9 pages)

Transportation Improvement Programs (TIPs) and Statewide Transportation Improvement Programs (STIPs) are transportation planning documents used by state DOTs and metropolitan planning organizations (MPOs) and required by the Federal Highway Administration (FHWA). TIPs and STIPs provide funding information for transportation projects that receive federal highway and transit funding, as well as state-funded projects.

Applications of Computational Fluid Dynamics for River Simulation: State of the Practice


(PDF, 212 KB, 11 pages)

The purpose of this technical report is to assist the State in determining the state of the practice of CFD for river simulation. The work focuses on investigating the following: Finding out how CFD is being used to model river flows around piers; single and parallel bridges; ice and debris; bendway weirs and other river training structures; Determining if CFD has been used to simulate sediment transport and scour under bridges with and without piers; and Identifying who (which state DOTs) uses CFD for the above mentioned purposes, what software is being used, what this software costs, and the cost to conduct studies of this kind.

Investigation of Performance Requirements of Full Depth Reclamation Stabilization


(PDF, 2 MB, 19 pages)

The Minnesota Department of Transportation recognizes the value of the pavement recycling process called Stabilized Full Depth Reclamation (SFDR) and wishes to promote further usage. But before widespread application of SFDR is attainable, it is imperative that the performance requirements for SFDR be determined. Since there is an absence of such a specification in Minnesota, the structural capacity of SFDR may not be fully attained. The objective of this research project is to determine optimal properties that SFDR material should attain to be used as a base layer for hot-mix asphalt (HMA) roadways.

Quantifying the Economic Impact of Bicycling: A Literature Review with Implications for Minnesota


(PDF, 629 KB, 33 pages)

This document responds to the Minnesota Department of Transportation's Transportation Research Synthesis (TRS) request, May 2013, related to biking and its economic impact. The TRS instructed the team to: Compile previous efforts that quantify the economic benefits of bicycling, respond to the sectors and benefits outlined in the TRS request (health, employment, recreation, transportation, quality of life, and tourism), and identify methodologies in existing literature to quantify the described benefits, and pay special attention to work completed in Minnesota and identify areas where findings of economic impact are robust and areas where more work is necessary to understand the economic impact of bicycling in Minnesota

Bridge Safety Inspection and NBIS Bridge Inspection Program Administration


(PDF, 207 KB, 16 pages)

The Minnesota Department of Transportation has been actively working in recent years to develop a comprehensive bridge inspection manual. The intent of this manual is to address all aspects of bridge inspections including administrative policies and procedures, field inspection procedures, a state-specific recording and coding guide, and procedures for maintaining a bridge management system. The purpose of this research project was to review the current “State of Practice” in other states with regard to bridge safety inspections and NBIS bridge inspection program administration, identify any “Best Practices”, and then utilize this information as appropriate to enhance the program in Minnesota.

Cost Sharing Policies of State Transportation Agencies


(PDF, 4.2 MB, 48 pages)

State transportation agencies often enter into cooperative construction projects with local units of government where a mutual benefit and demonstrated transportation need exist. Determining which party is responsible for costs is typically defined in either legislation or in agency policy. State agencies are increasingly embracing a broader and more multimodal definition of transportation need often articulated in statewide multimodal plans and "complete streets" policies.

Pedestrian Snow Removal Best Practices and Lessons Learned


(PDF, 381 KB, 20 pages)

The Minnesota Department of Transportation (MnDOT) is currently reviewing its policy on snow and ice removal from pedestrian and bicycle facilities. This report serves to provide MnDOT with a comprehensive review of existing practices and policies from other states, as well as a summary of valuable publications that could be referenced while developing a new policy.

Asset Management for Retaining Walls


(PDF, 2.74 MB, 42 pages)

MnDOT would like to create an asset management plan for retaining walls and develop a proposal for a project to obtain inventory and condition information about metro retaining walls. To support these efforts, MnDOT is interested in the best practices and lessons learned from other transportation agencies with such programs. While most transportation agency retaining wall asset management programs are in their beginning stages, we found a significant amount of useful guidance about developing such a program.

The Use of Life-Cycle Cost Analysis to Evaluate Public-Private Partnerships


(PDF, 6.42 MB, 350 pages)

Supplemental Materials:
Georgia DOT 1 (XLSX, 371 KB), Georgia DOT 2 (XLSX, 402 KB)

MnDOT would like to compare traditional procurement options to the design-build-finance-operate-maintain (DBFOM) approach in public-private partnerships (P3) involving concession agreements so that it can estimate the proper valuation of private sector proposals. To do so, MnDOT needs information about conducting lifecycle cost analyses (LCCAs) of corridor, bridge and multi-modal projects to forecast operations and maintenance (O&M) costs over the long term. This information will help support MnDOT’s Alternative Transportation Finance, Sustainability, Asset Management and Bridge Risk Infrastructure Management initiatives.

To meet this need, CTC & Associates conducted a literature review and interviews with experts from several departments of transportation (DOTs) about the use of LCCA for comparing traditional procurement options to P3 concessions projects. We found little direct information about the use of LCCA specifically for P3 projects, although there is a significant amount of guidance and research related to value for money (VfM) comparisons of public procurement options to P3 proposals, and to LCCA in general. Interview results suggested that states are using consultants to estimate the long-term O&M costs of projects, however, it is unclear whether consultants have a formal LCCA methodology for estimating such costs.

Mobile Traffic Signals in Lieu of Flaggers for Moving Operations


(PDF, 552 KB, 7 pages)

Flagging in work zones is crucial to the safety of workers and drivers, but it is one of the most dangerous tasks, representing more than one-third of injuries to pedestrian workers. Automated Flagger Assistance Devices (AFADs) are portable traffic control systems that can help to improve safety because flaggers can operate them from outside the flow of traffic. Several states have evaluated AFADs, with generally positive assessments of their effectiveness. While compliance with the AFAD is not universal among drivers, violation rates were lower than red-light violation rates documented in other literature. MnDOT requested information about self-propelling AFADs for mobile work zones, with the specific idea of mounting an AFAD on a remote-controlled caravan mover.

Culvert Designs for Aquatic Organism Passage: Culvert Design Practices Incorporating Sediment Transport


(PDF, 525 KB, 19 pages)

The design of culverts to accommodate aquatic organism passage (AOP) requires an understanding of organism habitat requirements, swimming ability and migration needs, as well as an understanding of how a culvert design will perform in a specific geomorphic context. This report documents existing reports on culvert design for AOP in Minnesota and nationally. It is designed to build upon the work of Hansen et al. 2009 and 2011 to: 1) summarize current aquatic organism passage practices, 2) summarize aquatic organism passage needs for Minnesota species, 3) discuss the importance of roughness or streambed sediment within a culvert in different systems (high, medium, or low slope) in single and multiple barrel systems, and 4) summarize physical experiments of sediment transport and geomorphic processes through culverts.

Performance-Based Specifications for Temporary Erosion and Sediment Control During Construction: A Survey of State Practice


(PDF, 127 KB, 9 pages)

During construction projects, surrounding soils can be disrupted, causing ecological damage through topsoil erosion and pollution of waterways with sediment. MnDOT currently has requirements and inspection procedures to ensure that contractors take measures, typically referred to as best management practices (BMPs), to control this erosion and sediment. Compliance is financially assured via a lump sum payment: Contractors who follow the requirements get paid upon completion of work according to specifications. MnDOT is looking into the prospect of applying more innovative modes of contracting to manage this process. Performance-based specifications would provide rewards for outcomes instead of for simply following MnDOT-required procedures. Contractors could apply new techniques and technologies to address this problem at their own initiative, encouraging faster applications of innovation and making management simpler for MnDOT while granting contractors more discretion. We surveyed other state departments of transportation to assess their experience with performance-based specifications in this area. As part of the survey, we requested guidance for configuring specifications and contract mechanisms, communicating with contractors about erosion and sediment control, and determining whether requirements have been met.

Ultra-Thin Polymer Concrete Overlays for Bridge Decks


Bridge Overlay

(PDF, 3.7 MB, 17 pages)

Ultra-Thin polymer concrete overlays for bridge decks improve the friction and durability of bridge decks while sealing them against the corrosive effects of deicing chemicals. However, there are concerns that these overlays may trap water in the concrete surface, accelerating deterioration due to freeze-thaw cycles. MnDOT needs more information on the effectiveness of thin overlays in extending the life of bridge structures, the effectiveness of overlays in reducing accidents by increasing friction, and the performance of overlays over time.

State Highway System Classification and Investment: A Survey of Practice


(PDF, 9.9 MB, 116 pages)

Appendix H

(Excel 232KB)

MnDOT is interested in learning how other states align ownership with function, set standards and establish investment levels for state highway systems. MnDOT is also interested in how changes in the state highway system over time are reflected in funding priorities and modifications in ownership arrangements.

Integrated Corridor Management: A Review on the Theory and Practice


(PDF 238 KB, 9 pages)

Integrated Corridor Management (ICM) is believed to be an effective way to reduce congestion and enhance safety by appropriately diverting the traffic to parallel routes containing unused capacity. Numerous ICM conceptual frameworks, models, and solution approaches have been introduced in the literature; some of them have been implemented and evaluated in the field. The aim of this article concentrates on documenting the existing ICM schemes and their field evaluations, and summarizing the lessons learned from the previous research and implementation efforts. We hope the review of the existing literature and the summary of the ICM practice can help readers gather a comprehensive overview of ICM, and inspire further thinking on the improvement of ICM.

Culvert Repair Best Practices, Specifications, and Special Provisions: Task C Research Synthesis


(PDF 142KB, 10 pages)

This document contains the results of Task C, Research Synthesis, for the Culvert Repair Best Practices, Specifications and Special Provisions Guidelines Project. These guidelines will provide guidance to MnDOT engineers in making better decisions on culvert repairs. New materials specifications and special provisions will ensure adherence to standardized practices and increase the effectiveness and longevity of repairs. Focus will be on repair of centerline culverts of 24-inches to 72-inches in diameter.

Power Sources for Automatic Traffic Recorders


(PDF 979 KB, 28 pages)

Image of Power Source

The Minnesota Department of Transportation (MnDOT) currently completes traffic counts, classification counts, and speed counts using a number of sources. These include road tube counters, permanent Automatic Traffic Recorder (ATR) stations, permanent Automatic Detector Recorder (ADR) stations, weigh-in-motion sites, and portable ATRs, specifically using Wavetronix SmartSensors. All of these detections methods require power, but the needs vary greatly depending on the type of detection system. The permanent stations utilize hard wired or ―grid‖ power from local power companies. The cost of this can vary but getting onto the power grid is deemed to be worth the effort and cost to have a reliable source of power for locations that will be collecting data every day of the year for many years, such as at permanent ATR and ADR stations. The focus of this research will be on portable power sources to power the Wavetronix SmartSensor HD system that MnDOT currently employs for some of their traffic counting efforts.

Collecting and Managing Traffic Data on Local Roads


(PDF 1.4 MB, 77 pages)

Appendix A

(Excel 40 KB)

Appendix B

(Excel 19 KB)

MnDOT is investigating alternatives to this primarily centralized approach to gathering traffic counts. To support this effort, this report examines traffic counting practices on local roads from five perspectives:

  1. Current MnDOT traffic counting practices
  2. Traffic counting technologies appropriate for temporary deployment
  3. Literature review of traffic counting practices on local roads
  4. Surveys of statewide participants in MnDOT's traffic data collection program (initial and supplemental surveys)
  5. Survey of state DOTs' local road traffic data collection practices

Traffic Forecasting on Trunk Highways in Nonmetropolitan Areas: A Survey of State Practice

TRS 1206

(PDF 1.6MB, 32 pages)


(Powerpoint, 724 KB, 23 slides)

Traffic forecasting plays an important role for MnDOT in corridor planning, geometric design, pavement design, safety analysis, benefit/cost analysis, access management, and environmental analysis and mitigation. In previous decades, Minnesota has seen steady growth in vehicle miles traveled. However, in recent years VMT growth in Minnesota has been flat and declined by 0.5 percent from 2009 to 2010.

MnDOT is interested in learning how other states are dealing with what appears to be a nationwide trend in a leveling off or decline in VMT, and what forecasting methods are used by state DOTs to project traffic volumes in nonmetropolitan areas with a population under 50,000.

Mitigating Highway Construction Impacts with Transit


(PDF. 278 KB, 12 pages)

This TRS is provides a summary of research done on how to mitigate the impacts of highway construction projects through the use of transit and what strategies can be used to retain riders it after a highway construction project is done

Methods for Setting Posted Speed Limits


(PDF, 235 KB, 17 pages)

Traditionally, Minnesota's posted speed limits are determined using the Institute of Transportation Engineers methodology as well as other considerations. The ITE methodology uses field measurements to evaluate roadway segments for the speed at or below which 85 percent of free flowing vehicles are traveling. MnDOT has observed that the ITE methodology often determines a higher operational speed for two-lane rural highways than MnDOT believes is warranted by other engineering and safety considerations. Further, MnDOT is being asked to justify posted limits of 55 mph when statutory limits for such roadways in Minnesota are 65 mph.

Consequently, MnDOT would like to identify alternative methods used for determining posted speed limits that produce greater compliance by motorists.

Innovative Bridge Construction


(PDF 7.6 MB, 40 pages)

Minnesota counties have been actively implementing new design and construction techniques for multiple projects in recent years. In June of 2011, the Local Road Research Board (LRRB) discussed and approved preparing a synthesis report to document several of these projects.

Scanning tours have previously been conducted to investigate bridge design and construction methods used in other states. Staff from the MnDOT State Aid Office and the Bridge State Aid Unit, representatives from the Minnesota County Engineers Association, and FHWA have participated in the scans. Several of the technologies identified during these scans have since been applied to local bridge construction on Minnesota projects, and are included in this synthesis.

Far -Field Testing of Noise Wall Effectiveness: Survey of State Practice and Literature Scan


(PDF, 320 KB, 7 pages)

Before performing a formal investigation involving such "far-field" testing to confirm MnDOT's view that far-field noise levels do not increase with the installation of noise walls, CTC & Associates was asked to review noise wall testing research and guidance, and contact national experts to determine whether such testing has been performed elsewhere. The scope of this investigation also includes determining how other state departments of transportation have responded to similar complaints. This review doesn't include noise generated by reflection between parallel barriers; Minnesota is investigating this issue by other means.

Impact of Vibratory Equipment to Surrounding Environments during Construction


(PDF, 234 KB, 13 pages)

MnDOT is interested in the conflict resolution process surrounding the impact of vibratory equipment, including impact or damage to property, best practices for public engagement during large projects, educating the public about the potential for damage during construction, and construction in areas susceptible to damage.

A survey of MnDOT personnel, a survey of state DOTs, and a literature search were performed, focusing on MnDOT current practices, and other state DOT practices that address the conflict resolution process for vibration-producing activities such as compaction, pile driving, blasting or pavement breaking.

Bridge Deck Cracking


(PDF, 172 KB, 11 pages)

Cracking in bridge decks has been a main concern of bridge designers and owners for decades. Various contributing factors have been identified but their relationships are not fully understood.

The Minnesota Department of Transportation has collected data during construction of bridges between the dates of approximately July 2005 and present. The data includes construction practices and environmental conditions during construction, and bridge inspection results. To prepare for a larger study to analyze this data, this report examines previous studies for the causative factors of bridge deck cracking, a Transportation Research Synthesis (TRS).

Use of Social Media by Minnesota Cities and Counties


(PDF, 534 KB, 18 pages)

Minnesota's Local Road Research Board (http://www.lrrb.org) is interested in knowing the extent to which Minnesota counties and cities are using social media: Which social media outlets are they using? How are they using them? Of particular interest are transportation-related communications through social media channels.

LRRB requested a nonscientific scan of counties and larger to help establish the scope of social media use by local governments for transportation purposes throughout the state of Minnesota.

Small MPO Funding


(PDF, 302 KB, 42 pages)

This report looks at how state DOTs and regional-level MPOs (Metropolitan Planning Organizations) coordinate funding estimates for long-range plans. It looks at whether state DOTs are directive about the funding estimates used by MPOs in their long-term plans and if so, how they do this. It also looks at how MPOs accommodate uncertainty in their funding estimates. This study also looks at how MPOS select projects and how state DOTs interact in these processes.

Estimating Non-Automobile Mode Share


(PDF, 101 KB, 8 pages)

This research reports on whether and how other states gather and analyze data or estimate mode share (transit, bicycling, or walking) for travel statewide. This research found that many states do not provide information on current bicycle and pedestrian mode share. Those states that do report this information, report either Census data or from their own travel behavior inventories if they are at all current.

Snow Plow Cutting Edges for Improved Plowing Performance, Reduced Blade Wear, and Reduced Surface Impacts


(PDF, 97 KB, 12 pages)

This report aims to provide MnDOT Maintenance and local agency winter maintenance units with a concise research synthesis on snow plow cutting edge research. This research synthesis provides a single source with which maintenance managers may use in decision making in regard to purchase and use of snow plow cutting edges.

Effects of 24-Hour Headlight Use on Traffic Safety


(PDF, 3.3 MB, 80 pages)


Daytime running lights—generally low-wattage headlights that turn on automatically when a vehicle’s ignition is started—are a safety feature intended to reduce multiple-vehicle crashes during daylight hours by making vehicles more conspicuous to other drivers. In some countries, such as Canada, they are required to be standard equipment on all vehicles manufactured; in the United States they are permitted but not required, and were standard equipment on about 27 percent of new vehicles manufactured in 2005 (NHTSA, 2008).

Potential Benefits to the Freight Industry of Distance-Based Road User Fees


(PDF, 955 KB, 34 pages)


As vehicles become more fuel efficient, fuel taxes are producing less revenue for road construction, operations and maintenance. As a consequence, states are exploring replacing these taxes with other userbased revenue sources, such as mileage-based road user charges, also referred to as vehicle-miles-traveled fees. These approaches may also have the benefit of reducing highway congestion if pricing is varied by level of congestion. The commercial freight industry agrees that distance-based pricing, especially as it relates to congestion pricing, has system management and revenue benefits for transportation agencies but is skeptical about benefits to the industry and believes such fees will be more costly than current fuel taxes.

Decision Tree for Unpaving Roads


(PDF, 955 KB, 34 pages)

The Minnesota Department of Transportation and the Local Road Research Board initiated a preliminary investigation into the issues surrounding the maintenance, preservation and possible conversion of low-volume paved roads to gravel. Rising costs of pavement materials and stagnant or declining funds for road construction and maintenance prompted the agencies to begin looking into issues surrounding the decision to unpave low-volume roads. To assist in the process and to provide
MnDOT and the LRRB with the best, most up-to-date information, CTC & Associates was asked to review the issues associated with the decision to convert paved low-volume roads to gravel roads. This research synthesis highlights relevant research and information related to road surfacing decisions, pavement preservation techniques, cost analysis and current road agency experiences.

Cadastral and Right of Way Data Sharing


(PDF, 108 KB, 8 pages)

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Local government agencies create, collect, compile, and store data that also have value to other state agencies, such as the Minnesota Department of Transportation (MnDOT). In turn, MnDOT also is a keeper of information that has value to local government agencies. Local government and state agencies create and maintain their cadastral and right of way data in varying ways and with different systems, and those differences pose one barrier to the sharing of that information. A 2002 initiative to develop a statewide parcel map inventory helped set the stage for several projects to improve data sharing of right of way and cadastral information between MnDOT and local government agencies. Recognizing the benefits of easy access to existing data among agencies, MnDOT began exploring potential solutions for sharing cadastral data between MnDOT and local government agencies. MnDOT relies on maps, deeds, and other right of way records from local government agencies when planning right of way options and acquisition needs. To investigate the potential, MnDOT sponsored a 2004 research project, Enhanced Coordination of Cadastral Data. The research evaluated the potential for sharing of cadastral data and outlined considerations for moving forward. In 2006, MnDOT launched an implementation pilot project in MnDOT Districts 3 and 4, which involved collaborations with local government agencies, technology development, launch of a web-based portal, and training and communication to support use. It also helped demonstrate the possibility for data sharing among state and local government agencies on a broader scale. This TRS highlights the benefits of improving access to data sharing, describes the implementation and research projects, provides an update on the status of implementation, and outlines next steps.

State DOT Experiences with Primavera P6 Project Management Software


(PDF, 146 KB, 11 pages)

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Minnesota DOT is considering various project management software applications for use in a range of highway construction activities. One of the applications under consideration is Primavera P6 Enterprise Project Portfolio Management software. The product is now available through Oracle, which acquired Primavera Software Inc. in October 2008. We were asked to survey several state DOTs currently using this application to gather preliminary information about its potential applicability to MnDOT.

CTC approached Oracle to identify states using Primavera P6. The Oracle representative we spoke with thought that the following 13 states were using P6: Connecticut, Florida, Illinois, Massachusetts, New Jersey, New Mexico, New York, Puerto Rico, South Carolina, South Dakota, Texas, Virginia and Washington. We queried DOT research directors for the names of Primavera managers we could interview and were able to identify appropriate individuals in the following state DOTs: Connecticut, Florida, New York, South Carolina, South Dakota, Texas and Washington. We also identified and interviewed the Primavera manager for the Port Authority of New York & New Jersey. Below are the questions we posed, based on input from the Mn/DOT team that is investigating the project management applications. Names and contact information for interviewees are included in the Interview Responses section that begins on page 4.

ADA Compliance Reference and Training Materials

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(PDF, 362 KB, 16 pages)

As part of the development of Minnesota DOT’s Americans with Disabilities Act Transition Plan, the department adopted Public Rights-of-Way Accessibility Guidelines as its primary guidance for public facility design. To fully implement PROWAG, MnDOT will be conducting departmentwide training on both design and policy. The department is developing ADA compliance training for MnDOT staff, local governments and consultants. To assist Mn/DOT in the development of curriculum modules and other training materials, CTC & Associates conducted a “state of the practice” review of relevant reference and training materials from federal agencies, advocacy groups and other state DOTs.

Developing a Culture of Innovation


(PDF, 8.3 MB, 87 pages)

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The ability to innovate is critical to an organization’s performance, especially for DOTs confronted with managing a large and complex transportation system. However, like many large organizations, DOTs typically resist change and are slow to innovate.

Minnesota DOT is interested in the steps other states have taken to encourage a culture of innovation among employees, including a work environment, organizational structures and operating procedures that reward exploration of new, more effective approaches to doing business.

We conducted a survey of state DOTs and performed a literature search, focusing on:

  • Challenges, opportunities and successes in developing a culture of innovation.
  • Organizational strategies for moving toward a culture of innovation.
  • The relationship of a culture of innovation to centralized or decentralized organizational structures.

Effectiveness of Traffic Signs on Local Roads

TRS Cover Page


PDF, 99 KB, 6 pages)

The 2009 edition of the Manual on Uniform Traffic Control Devices includes requirements for the management and maintenance of all roadway signs. Management of large numbers of signs can pose administrative and financial challenges for local road authorities. The Minnesota Department of Transportation is reviewing whether the removal of ineffective traffic signs may be part of an overall sign management strategy and has asked CH2M Hill to prepare a best practices guide for removing traffic signs. In support of this work, CTC & Associates was tasked by MnDOT with performing a literature search and synthesis of research demonstrating the effectiveness or lack of effectiveness of various types of traffic signs on local roads, including low-volume roads.

Effects of Major Traffic Generators on Local Highway Systems

Cover Letter


(PDF, 861 KB, 30 pages)

The Minnesota Department of Transportation initiated a study focused on the effects of major traffic generators on local highway systems. Minnesota State University and SRF Consulting Group, Inc. will conduct a major research study on the topic. To assist in that research CTC & Associates was asked to conduct a preliminary investigation focused on large wind farm developments, an increasingly common type of major traffic generators in Minnesota. The development of large wind farms necessarily includes the movement of very large, oversize trucks carrying wind turbines over county roads. This construction raises several concerns, including pavement damage; indirect impact to the immediate area surrounding the roads; and related costs to local governments to repair and maintain the roads and to mitigate other effects. The preliminary investigation focused on gathering information related to the two main areas of inquiry in the research project: calculating pavement damage and secondary impacts due to large vehicle traffic; and policy options for local governments to recapture the costs of roadway maintenance caused by wind farm development.

Issues of Concern Related to Underground Infiltration Systems for Stormwater Management & Treatment

Underground Infiltration System


(PDF, 1.2 MB, 13 pages)

This Transportation Research Synthesis (TRS) provides an overview of relevant literature, regulations, guidance, and other information related to a specific stormwater Best Management Practice (BMP), underground infiltration systems with sump manhole pretreatment. This TRS is intended to serve as part of the justification to prompt a review of this practice and related practices in the context of a revision to the Minnesota Stormwater Manual (MSWM).

Anti-icing in Winter Maintenance Operations: Examination of Research and Survey of State Practice

Winter Maintenance


(PDF, 490 MB, 32 pages)

MnDOT is developing an anti-icing guide that will be incorporated into the department’s existing winter training program. The guide will be used by front-line supervisors and managers to better manage their winter operations and by operators to assist them in effectively performing their snow and ice control duties.

 To prepare for development of the anti-icing guide, MnDOT asked us to review relevant research to identify existing anti-icing practices, field strategies and procedures, and application rates. We also reviewed 12 transportation agencies’ anti-icing guidelines and procedures to identify current patterns of practice.

Methods and Practices for Control of Canada Thistle

Canada Thistle


(PDF, 468 KB, 6 pages)

Recognizing the challenges in controlling the weed, Canada thistle, the Minnesota Department of Transportation (MnDOT) and the Minnesota Local Road Research Board (LRRB) have supported research on the topic. This synthesis offers a brief summary of that work and provides additional information about other national and international research, MnDOT methods and practices, other state department of transportation practices nationwide, and research in progress.

Transportation Research Synthesis: Planned and Unplanned Disruptions to Transportation Networks

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(PDF, 534 KB, 11 pages)

The collapse, on August 1, 2007, of the I-35W bridge over the Mississippi River in Minneapolis, abruptly interrupted the usual route of about 140,000 daily vehicle trips and substantially disturbed the flow pattern of the network. In addition to the heavy losses in life and injury, the network disruption has also significantly impacted road-users and reshaped travel patterns in the Twin Cities area, which could generate significant cost due to longer travel distance, higher levels of congestion, and the resulting opportunity losses. According to Minnesota Department of Transportation (MnDOT), rerouting alone could cost individual travelers and commercial vehicles $400,000 daily based on Metropolitan Council planning model. Xie and Levinson (2008) find a lower, but still large, estimate of expected costs to road users, between $71,000 and $220,000 per day. As a result, a significant financial incentive was given to the contractor for the early completion of the replacement bridge. A similar financial incentive was employed after the Northridge Earthquake in California...(read the synthesis)

Transportation Research Synthesis: Methods of Estimating the Economic Impact of Transportation Improvements

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(PDF, 191 KB, 15 pages)

When confronted with the problem of evaluating proposals for projects involving new highway capacity, public decision makers face a bewildering array of options for anticipating and assessing project-related economic impacts. On one hand, the issue of geographic scale is highly relevant. Local or project-level impacts may be very different from those estimated at regional and multi-regional levels. Another salient issue is that there are many metrics for assessing economic impacts, ranging from direct user benefits and changes in external costs of travel to more aggregate economic indicators, such as employment, income and productivity rates.

Several types of economic benefits arise from transportation improvements:

  • reductions in travel costs;
  • more efficient supply chains;
  • intra-firm scale economy effects (permitting individual firms to through larger scale operations at fewer locations);
  • agglomeration (including inter-firm scale effects) whereby clusters of competing and complementary firms perform better than firms in isolation; and
  • re-organizational benefits, where firms can reorganize the way they produce output, and improve quality or even the goods that can be produced thanks to new infrastructure, just-in-time production is an example.

Transportation Research Synthesis: Traffic Calming for High-Speed rural Roadways

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(PDF, 481 KB, 6 pages)

The Minnesota Local Road Research Board (LRRB) requested a synthesis of studies that explore the topic of traffic calming for high-speed rural roadways. The Federal Highway Administration (FHWA) offers a description of traffic calming that includes two components:

  • “The combination of mainly physical measures that reduce the negative effects of motor vehicle use and improve conditions for non-motorized street users.”
  • “A number of transportation techniques developed to educate the public and provide awareness to unsafe driver behavior.”

The FHWA and the Institute of Transportation Engineers (ITE) acknowledged the challenges in reaching a consensus on a definition of traffic calming in its publication, Traffic Calming, State of the Practices, 1999.

Transportation Research Synthesis: Transverse Rumble Strips

Rumble Strips


(PDF, 614 KB, 5 pages)

The Federal Highway Administration (FHWA) defines rumble strips “as raised or grooved patterns on the roadway shoulder that provide both an audible warning (rumbling sound) and a physical vibration to alert drivers that they are leaving the lane.” Cities and counties may use rumble strips as means of enhancing safety to help warn motorists to slow down in anticipation of a stop sign or to help warn motorists that they are leaving the roadway or crossing the centerline.

A Synthesis of Research and Resources on Local Road and Bridge Funding for Local Public Works Officials

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(PDF, 387 KB, 32 pages)

This project, sponsored by MnDOT’s Research Services Section, is an effort to identify the most relevant, useful, and applicable research on local transportation finance issues for local government practitioners in Minnesota. The editor, working with staff of the MnDOT Library, has reviewed hundreds of documents and other resources in an effort to identify those that have the most potential to directly assist local officials through better understanding of current and alternative funding policies, better awareness of existing analytical tools and other resources, and greater familiarity with available funding sources and procedures.