Effectiveness of Variable Message Sign Communication in Prompting Drivers to Slow Down and Move Over

Introduction

Roadside incidents remain a serious concern for the safety of service technicians and other roadside workers, despite Slow Down Move Over (SDMO) laws in all U.S. states. Recent AAA Foundation for Traffic Safety (AAAFTS) research has shown that variable message signs (VMS) can have beneficial effects on drivers’ SDMO behaviors and multiple AAA Clubs are deploying VMS to communicate with drivers. However, regulations vary widely in what types of messages, symbols, and directional cues can be used. The current project seeks to gather evidence on how drivers interpret and respond to different VMS message formats in the context of SDMO, or which messages most effectively convey the need to slow down and move over. 

Project Goal and Plan

This research project will review and synthesize the current state of knowledge on digital messaging, with focus on the types of messages, symbols, and directional cues used for VMS. Next, it will explore how different messages are interpreted, including different formats and texts, to assess public feedback on elements such as comprehension, driver action clarity, and overall message preference, and to identify which messages are most intuitive and acceptable. Finally, candidate messaging types will be evaluated in a controlled experimental study conducted in the AAAFTS Driving Simulation Laboratory to assess their effectiveness in influencing driver behavior for SDMO compliance.