Trailer trucks with rear extensions to reduce wind drag have become increasingly common on the highway. With the success of these truck-trailer tails, engineers wondered if the concept could help solve the problem of wind-induced vibrations of road signs as well.

Typically, roadside structures must feature breakaway mechanisms to reduce potential injuries to drivers and passengers, which means the support structures can’t be stiffened. “This makes heavier signs very susceptible to wind-induced vibrations that potentially cause the support structure, and any attached electric signs, to fail prematurely,” says Lauren Linderman, an assistant professor in the Department of Civil, Environmental, and Geo- Engineering (CEGE). In addition, the vibrations may make the signage less visible to drivers.

In a recent project, Linderman led a research team that studied the potential impacts of vibrations on large roadway sign panels, using a MnDOT rural intersection conflict warning sign (RICWS) for analysis. The goal was to understand wind-induced behavior and propose potential sign modifications. MnDOT and the Minnesota Local Road Research Board funded the project.