For more information, please visit: http://www.dot.state.mn.us/stateaid/ trafficsafety/retroreflectivity/signretroreflectivity-mn-toolkit.pdf.
To assist Minnesota local agencies conform to the federal mandate, the MN LRRB has created a toolkit to help local agencies develop a customized sign maintenance plan that considers each agency’s budget, resources, and sign inventory.
Traffic Sign Life Expectancy Research Project
This toolkit, available online, includes a variety of resources including: • Know Your Retro – Maintaining Sign Retroreflectivity • 2014 Traffic Sign Retroreflective Sheeting Identification Guide • MN Manual on Uniform Traffic Control Devices (MUTCD) Requirements • Sign Assessment and Management Methods Fact Sheet “Because local agencies have limited budgets and varying circumstances, it’s important that they be given all the available options for customizing a sign maintenance program to meet their specific needs,” says Michael Sheehan, Olmsted County Engineer.
As mentioned earlier, retroreflectivity is critical for nighttime visibility and driver safety. Knowing how long a sign will maintain adequate retroreflectivity helps to ensure roadway safety throughout the sign’s service life and saves money by avoiding unnecessary replacement costs. But how long do traffic signs really last? Unfortunately, there is limited data on the functional service life of traffic signs (particularly those using the newest sheeting materials). So to answer the sign life expectancy question, the MN LRRB has funded a new research project to develop expected sign life values, enabling local agencies to better manage their traffic sign assets. To begin studying retroreflectivity, Minnesota Department of
MnDOT researchers use a test deck to study various sign materials and develop expected sign life guidelines, enabling local agencies to better manage their traffic sign assets.
Transportation (MnDOT) researchers gathered a variety of roadside signs (along with each sign’s age, location, and installation records) from around the state. Researchers used these signs to create a test deck at its MnROAD Research Center (http://www.dot.state. mn.us/mnroad/map.html), where a team of experts is using this test deck (which includes several south-facing signs angled upward to accelerate deterioration) to study retroreflectivity and color readings. These findings will eventually help researchers determine the average useful life of sign sheeting material and develop best practices and sign maintenance policies. Preliminary data already suggests that traffic signs should be expected to last at least 15 to 30 years, which is longer than the typical manufacturer’s warranty. For more information on this expected sign life project, please visit: http:// www.dot.state.mn.us/materials/ signretroreflectivity.html.
Updated Traffic Sign Maintenance and Management Handbook Mandatory sign management plans benefit motorists as well as local agencies. These plans help ensure maintenance workers properly update their road signs to meet current safety and retroreflectivity standards. Proper sign management plans also allow local agencies to protect themselves against liability in the event of a crash. To assist local agencies in developing their required sign management plans, investigators recently updated MnDOT’s Traffic Sign Maintenance and Management Handbook. Designed to help agency employees better maintain their traffic signage, the guide includes sample documents, current policies, and money-saving tips for removing unnecessary signs, which can reduce maintenance costs by up to 30 percent. Other pertinent topics include:
July 2015 issue of the APWA Reporter, the official magazine of the American Public Works Association