2006 - 2005 Technical Summaries
Transit and Roadway Investment
Balancing Transit and Roadway Investment to Meet Twin Cities Travel Demand
Researchers examined the potential for different combinations of transit and roadway expansion to cost-effectively solve the growing problem of traffic congestion on freeways and expressways in the Minneapolis-St. Paul metropolitan area. They found that a critical factor in the solution is the level of service desired for the roadways.
“This research provides a timely look at options that may be more cost-effective than building roadways.”
– Mark Filipi, Manager, MTS Technical Planning Support, Twin Cities Metropolitan Council
Storm Water Management
Water Quality Performance of Dry Detention Ponds with Under-Drains
Investigators monitored the performance of three dry detention ponds regarding the amount of suspended solids and phosphorus left behind after storm water drained through them. These storm water management devices performed adequately compared to national standards
“Wet ponds present some maintenance difficulties. We feel dry ones are a good solution to wet pond problems. Monitoring data gave us something to work with, but we would have liked to see more design guidance from this study.”
–Scott Morgan, Mn/DOT District 7 Hydraulics Engineer
The Effect of Rumble Strips on Drivers Approaching Rural, Stop-Controlled Intersections
Researchers studied the stopping patterns of approximately 400 cars, trucks and other vehicles at selected rural intersections and found that in-lane rumble strips caused drivers to reduce speeds earlier and to a greater degree than at intersections without rumble strips. This was the third in a comprehensive series of studies on the effectiveness of in-lane rumble strips.
“This study provides counties with some justification for implementing in-lane rumble strips as well as useful information for formulating rumble strip policies.”
– Brad Wentz, Becker County Engineer
Load Rating of Composite Steel Curved I-Girder Bridges Through Load Testing with Heavy Trucks
Researchers investigated the behavior and load rating of a curved I-girder bridge by load testing the bridge and comparing the results with a grillage-based analysis model. They studied model parameters using the results of the tested bridge and two others tested elsewhere to assess the robustness of grillage analysis for load rating this type of bridge.
“This was an interesting project that provided valuable information on a complex analysis that can be used for future overweight permitting.”
– Edward Lutgen, Bridge Rating Engineer, Mn/DOT Office of Bridges and Structures
Construction Decision Rules and Performance Measures
Beyond Business as Usual: Ensuring the Network We Want Is the Network We Get
Researchers documented construction decision rules and performance measures, and then used these to compare computer models of alternative future states of the highway network. The models showed whether changing current construction decision practices will produce a better network. Researchers concluded that changing decision rules had little effect as compared to increasing the overall investment level.
“This project highlights the challenges of improving the performance of a mature transportation network, especially when resources are scarce and the competing demands are many.”
– Rabinder Bains, Economic Policy Analyst, Mn/DOT Office of Investment Management
Rural Intersection Safety
Safety Impacts of Street Lighting at Isolated Rural Intersections
Investigators quantified the effectiveness of roadway lighting as a tool for reducing nighttime crashes at isolated rural intersections. Based on positive results, the researchers recommended that Mn/DOT consider revising its lighting guidelines to apply to a higher percentage of rural intersections, provide quantifiable volume and crash measurements, and consider roadway functional classification.
“The results of this study can help to facilitate the use of intersection lighting by all Minnesota highway agencies.”
– Roger Gustafson, Carver County Engineer
Seal Coat Handbook
Putting Research into Practice: Minnesota Seal Coat Handbook 2006
This project updated the extremely popular 1998 handbook and created an accompanying training module in light of recent Mn/DOT seal coating studies, specifications and field experience. The updated handbook covers additional seal coat uses such as fog sealing to rejuvenate pavements and chip sealing on recreational trails.
“The original handbook was Seal Coating 101, aimed at people who had previously had bad experiences with the practice. The update was to take that audience to the next level in seal coating and broaden their applications of this technology.”
– Mark Maloney, Public Works Director, City of Shoreview
Concrete Repair Handbook
Putting Research into Practice: Field Handbook for Concrete Repair for Local Streets and County Roads
Investigators drew on county expertise and Mn/DOT specifications to create a streamlined field handbook and accompanying training that present standard plates and step-by-step design and construction guidance for use on low-volume concrete roads, sidewalks, and curbs and gutters.
Technical Summary: 200631TS (PDF)
Handbook: 2006-31 "Field Handbook for Concrete Repair for Local Streets and County Roads" (PDF)
“Mn/DOT concrete rehabilitation standards are numerous; you have to work in this area day in and day out to keep up with them. We wanted to create a simpler, one-stop resource for use on-site.”
– Michael Sheehan, Olmsted County Engineer
Improving Road Safety with Two-Way Left-Turn Lanes
Researchers examined the effect on safety and operations of converting traditional four-lane roadways to three-lane roadways with two-way left-turn lanes by analyzing before and after data from nine Minnesota sites. They found that such conversions can improve safety with little impact on operational conditions.
“This study confirmed the findings of other states—that converting four-lane undivided highways to three-lane highways with left-turn lanes can increase safety without negatively impacting operations.”
– David Engstrom, State Traffic Safety Engineer, Mn/DOT Traffic, Safety and Technology
Hear Every Voice II
Putting Research into Practice: Managing Conflicts Arising from Public Involvement in Transportation Projects
Investigators conducted interviews to refine a previously established system for categorizing and addressing conflicts with the public that arise during transportation projects. They then created a document to implement this system for use in the new version of Mn/DOT’s public involvement manual.
“We are currently revamping our statewide public involvement guidance as Hear Every Voice II in accordance with SAFETEA-LU. This research will serve as valuable information for project managers when HEV II is released.”
– Lynne Bly, Statewide Transportation Planning Unit Supervisor, Mn/DOT Office of Investment Management
Storm Water Management
Impact of Alternative Storm Water Management Approaches on Highway Infrastructure
Investigators conducted a survey and performed inspections to evaluate the performance of various storm water Best Management Practices and whether they negatively impact adjacent roadways. No negative infrastructure effects were discovered.
“Roadway designers, planners and engineers had a very important question: Do storm water management practices affect pavement life?”
– Dr. Alan Rindels, Mn/DOT Senior Engineer
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