Tag Archives: pavement markings

Using a National Database to Develop Performance Metrics for Local Pavement Markings

Pavement marking performance metrics from a new study will help Minnesota local agencies save time and money by choosing longer-lasting pavement marking products.

Researchers developed pavement marking performance metrics for Minnesota local agencies to use as a guide to make better pavement marking product decisions. The metrics were developed based on an analysis of survey data collected from Minnesota local agencies and MnDOT pavement marking data mined from the National Transportation Product Evaluation Program (NTPEP). Findings showed differences in product performance with regard to retroreflectivity and service life, which were impacted by variables such as road surface type, year of application, traffic volume and type of pavement marking.

“There would be great potential savings in using pavement marking products with a longer service life. Mining NTPEP data to analyze product performance has not been done before and should contribute substantially to this goal,” said Omar Smadi, Director, Iowa State University Center for Transportation Research and Education.

What Was Our Goal?

The goal of this research was to develop pavement marking performance metrics for Minnesota local agencies to use as a guide when choosing the most durable and cost-effective products. Researchers developed the pavement marking performance metrics, specifically for retroreflectivity and service life, by analyzing existing MnDOT data mined from NTPEP. They also used the findings to make recommendations for future pavement marking research to support local agency needs.

What Did We Do?

Researchers designed and conducted a survey to assess pavement marking products used by local agencies in the state. Then they extracted 2010 and 2013 MnDOT pavement marking data from NTPEP to analyze the performance of products that survey respondents identified as commonly used.

NTPEP data included products tested at two different sites and applied on different road surfaces. Researchers analyzed performance with regard to retroreflectivity and deterioration or longevity of the materials under various conditions, such as road surface type, year of application, traffic volume and type of pavement marking. Based on results from the analysis, researchers developed performance metrics for Minnesota local agencies to use as a guide for choosing particular pavement marking product types.

What Did We Learn?

From the survey results, researchers learned that the majority of Minnesota local agencies use either latex or epoxy as their primary pavement marking material. However, epoxy and tape outperformed latex at all levels of conditions and provided a service life of three years or more.

A few survey respondents also reported grooving as a method that seemed to extend the service life of latex paint markings. Researchers were unable to investigate the impact of grooving, however, since MnDOT grooving data was not accessible.

2017-43-p2-image
Grooving may extend the service life of pavement marking materials.

From the NTPEP data analysis, researchers concluded the following:

  • White markings had significantly higher initial retroreflectivity and slower deterioration than yellow markings.
  • Road surface type does not significantly impact retroreflectivity throughout its service life.
  • Epoxy has higher retroreflectivity than latex materials.
  • As expected, markings on wheel zones deteriorated faster, reducing retroreflectivity over time.
  • Deterioration values of markings varied among different test sites, which may be attributed to differences in average annual daily traffic (AADT) values (10,000 in 2010 versus 37,000 in 2013) or installation practices.

“The findings from this research will be beneficial for Minnesota local agencies in determining which pavement marking materials are most effective,” said Kate Miner, then-Scott County Traffic Manager.

What’s Next?

Although the product performance metrics data will help Minnesota local agencies make better pavement marking product decisions in less time, researchers recommend developing a guidebook to make the information more usable. Adding grooving data to the guidebook would also be beneficial to investigate the potential impact grooving provides in extending the service life of pavement markings.

Researchers also recommend testing the same products evaluated in this research on low-volume local roads and on challenging surface types. MnDOT NTPEP data only included products that were tested on high-volume freeways.

This blog pertains to the Local Road Research Board-produced Report 2017-43, “Minnesota Local Agency Pavement Marking: Mining Existing Data,” published November 2017. A related project has developed a spreadsheet tool to help local agencies prioritize pavement markings on low-volume roads.

Robotic message painter could help keep road crews safe

Using rollers and stencils to draw turn arrows and crosswalk stripes on roads seems a bit archaic to MnDOT District 3 Maintenance Superintendent Randy Reznicek, who asked researchers if they could develop an automated road message painter.

University of Minnesota-Duluth Associate Professor Ryan Rosandich has taken that vision and created an robotic arm that can spray-paint pavement signs, with the goal of saving crews time and keeping them safer.

Designed to be mounted to the front of a maintenance vehicle, the robot is operated remotely by a laptop, programmed with numerous types of messages.

In an earlier prototype, researchers developed a trailer painter that could be pulled behind a truck.

Crews currently use heavy, eight-foot by four-foot stencils and rollers to paint designs, with an estimated 75 percent of such work involving the repainting of existing markings.

“It takes two people to lift the stencils,” explained MnDOT maintenance worker Joe Gilk, whom Reznicek presented with the idea about five years ago. “This would eliminate one position. One person could just run the truck and you could use that other person in another area of our job.”

Rosandich, who heads the Mechanical and Industrial Engineering Department at the University of Minnesota-Duluth, led the initial development of a software system and trailer painter.

MnDOT has funded further research to develop the more technically difficult robotic arm, which it anticipates could be used in other aspects of maintenance work as well.

MnDOT District 3 maintenance worker Joe Gilk, left, and maintenance superintendent Randy Reznicek watch the demonstration of the robotic message painter, an idea that came from their office.
MnDOT District 3 maintenance worker Joe Gilk, left, and District 1 traffic engineer Rob Ege watch a demonstration of the robotic message painter, an idea that came from Gilk’s office.

Rosandich recently demonstrated the mechanical arm to a MnDOT road crew (no paint was used during the demonstration), but additional software and mechanical tweaks remain before researchers take the machine out for final testing on the pavement this spring.

A companion vision system is being developed to identify existing markings to guide the robot in the repainting of existing messages.

The robot’s three-segmented aluminum shell arm is capable of painting up to a 12-foot wide lane and has enough battery power for a whole day’s worth of work, Rosandich said.

Once the prototype is complete, researchers hope to find a manufacturer to develop and produce a machine that could be used by maintenance crews across the state. MnDOT has already had great success in deploying automated pavement patching systems in some districts.

Not only would a robotic message painter free up maintenance crews and speed up sign-painting, but Rosandich sees worker safety as its “biggest selling point.”

The start-up cost for manufacturing such a device is estimated to be $150,000.