The barrier markers are typically installed on the top of concrete barriers or other delineators to visually enhance the alignment. The markers were installed on a construction site in Salem, along the northbound right shoulder of I-5 near Silverton Road, as shown below. Prior to installation, the retroreflectivity of each marker was measured in the ODOT Materials Laboratory. The markers were removed 6 months after installation and the retroreflectivity was measured in the lab again to determine the impacts of dirt and wear on performance. The markers were then cleaned by washing with soap and water and tested a third time.
Washing can restore most of the markers' reflective properties.
At a minimum, the markers should be cleaned in the spring. The markers should also be cleaned when visual observation indicates that dirt collection may impair the effectiveness. Construction projects should include a requirement to periodically inspect the markers and clean them as directed by the Engineer. Maintenance crews should be aware of the reduced performance associated with field conditions and schedule periodic inspections. Regular intervals for cleaning are difficult to set because of variable field conditions.