Avoid Using Safety-Related Message Content on Dynamic Message Signs as a Standalone Strategy.

Researchers Used Surveys, Crash Data Analysis, and Field Observational Studies to Assess the Effectiveness of Safety-Related Messages Displayed on Dynamic Message Signs in Michigan.

Date Posted

Effectiveness of Crash Fact/Safety Message Signs on Dynamic Message Signs

Summary Information

Dynamic message signs (DMS) are electronic road signs, usually located along highways or major arterials, which can display messages selected by local or state Departments of Transportation. Typically, DMSs are used to display traffic information, weather information, or safety-related messages. 

A research team at Michigan State University conducted a mixed methods analysis to understand potential impacts on driver behavior and safety from displaying broader safety-related information, such as fatality statistics, on DMSs in Michigan. Analyses included:

  • A media content analysis that investigated public sentiment towards DMSs in emails to Michigan Department of Transportation, in Tweets, and in statewide news coverage in Michigan
  • A survey of Michiganders to understand their attitudes towards DMSs
  • Detailed spatial analysis of the relationship between DMS safety-related message display and crash frequency along Michigan roads
  • Field evaluations of driver response to DMSs along two Michigan highways, based on analysis of video and LIDAR data to assess driver speed changes
  • Public feedback was generally supportive of DMS messages, especially to display traffic and weather related information.
  • Displaying safety-related messages on DMSs had no statistically significant effect on crash rates.
  • DMS messages should be relevant to the road context in which they are displayed. For example, it would not be appropriate to display messages about school bus stop safety along roadways where there are no stops.  
  • Analysis of lane change behavior in response to "move over slow down for emergency vehicles" messages was affected by a confounding factor due to presence of traffic in the adjacent lane. However, compliance was found to be noticeably higher when a police vehicle was stopped on the shoulder as compared to a DOT vehicle, regardless of sign content.
  • A lack of significant observed driver speed changes in response to DMS messages suggests that using DMS content alone was not a promising strategy.

Effectiveness of Crash Fact/Safety Message Signs on Dynamic Message Signs

Effectiveness of Crash Fact/Safety Message Signs on Dynamic Message Signs
Source Publication Date
Savolainen, Peter T.; Timothy J. Gates; Eva Kassens-Noor; Megat-Usamah Megat-Johari; Nusayba Megat-Johari; Travis Decaminada; and Meng Cai
Prepared by Michigan State University for Michigan Department of Transportation
Other Reference Number
Report No. SPR-1686
Goal Areas

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