For more than 50 years, the Local Road Research Board (LRRB) has brought important developments to transportation engineers throughout Minnesota. Those developments range from new ways to determine pavement strength to innovative methods for engaging the public. Today, the LRRB remains true to its important mission: supporting and sharing the latest transportation research applications with the state’s city and county engineers.

Hot Topics

Younger Drivers Toolkit for Local Agencies

Traffic crashes are the leading cause of death for Minnesotans under the age of 29. This new MnDOT/LRRB publication provides city and county transportation staff with information to help engage local communities in improving safety for the state's highest risk drivers. The toolkit provides research explaining attitudes and motivations for high-risk driving among 15- to 29-year-olds and strategies to promote change, including policy, outreach and enforcement. Specific resources include sources for public service announcements, partnership opportunities and a PowerPoint presentation that can be tailored for specific programs.
Click here for the Toolkit and here for the PowerPoint presentation
September 17, 2015

Traffic Sign Replacement Research

Traffic sign replacement is a tricky business. Waiting too long might endanger lives and expose an agency to a lawsuit. But replacing traffic signs prematurely could cost a single city tens of thousands of dollars per year. If fully implemented, new recommendations developed by MnDOT and the Local Road Research Board (LRRB) could save public agencies as much as $41 million over three years by helping them better manage their signs and meet new federal requirements on retroreflectivity without replacing signs prematurely. A recent LRRB study, which consulted other states’ research and examined signs in the field, determined that the life of the modern sign in Minnesota is at least 20 years, and signs may retain their retroreflectivity for 30 years or more. A test deck at the MnROAD facility will track the condition of Minnesota signs over the next decades — and perhaps push the recommended replacement cycle longer.
To read the full article on the Crossroads blog, click here.
For further details, see the full Report, Technical Summary, or
Traffic Sign Maintenance Handbook
March 12, 2015

Why is All the Colored Concrete Deteriorating So Fast?

Across Minnesota, many of the estimated 45 colored concrete projects have experienced early deterioration, particularly microcracking near contraction joints. Early cracking has prompted the city of Vadnais Heights to tear up its colored concrete, and the city of Centerville —which installed colored concrete only six years ago— plans to follow suit. Both cities participated in a recent study, sponsored by the Local Road Research Board and conducted by MnDOT, to determine what is causing the early deterioration.
Click here to read the full article.
November 24, 2014