Effectiveness of Green Strobes on Winter Maintenance Vehicles and Equipment

Snow removal and deicing activities are performed by roadway agencies to enhance winter mobility and safety. Due to slower travel speeds during these operations, low visibility and reduced pavement friction, safety and collision avoidance remain persistent concerns. To improve the visibility of winter maintenance vehicles, the Michigan Department of Transportation (MDOT) has added green lights to the warning system of winter maintenance trucks (WMTs) since 2016. This study investigates the degree to which the visibility can be affected by including these green lights. First, the current state of practice by all state transportation agencies is explored through a comprehensive survey that shows most agencies consider using alternate colors in addition to amber. To evaluate impacts of adding green lights to the warning system of WMTs in terms of visibility, 37 warning light configurations are generated using various color combinations (green and amber) and flashing patterns (single and quad) on the back side (LED) and/or top (beacon) of the WMTs. These configurations are evaluated to identify the most effective ones based on feedback provided by several expert and public panels. Three sets of experiments (static, dynamic and weather) are designed and implemented to evaluate the visibility effectiveness in different contexts (day versus night conditions, clear versus snowy weather and static versus dynamic scenarios). Each of these experiments contains multiple tests that aim to identify different measures to assess the light configuration efficiency. Panels of experts and from the public are employed to conduct the experiments, and the test results are evaluated using statistical analyses. Conspicuity during the day and glare at night are the two main criteria with statistically significant results that are used to compare various configurations. The results show that adding green lights with a single flash pattern to amber warning lights improves the conspicuity significantly, while keeping the glare at an acceptable level relative to configurations using only amber warning lights.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 98p

Subject/Index Terms

Filing Info

  • Accession Number: 01762657
  • Record Type: Publication
  • Report/Paper Numbers: SPR-1692
  • Contract Numbers: 2019-0442
  • Created Date: Jan 4 2021 12:09PM