Evaluation of the Fredonyer Pass Icy Curve Warning System

The Fredonyer Pass Icy Curve Warning System (ICWS) was deployed by Caltrans to increase motorist vigilance and reduce the number of crashes occurring during icy pavement conditions in realtime. The ICWS consists of pavement sensors to detect icy conditions, in combination with dynamically activated signage to provide motorists with real-time warning when icy conditions are either imminent or present. The system is intended to alert motorists of icy conditions, eliciting a decrease in vehicle speeds during such conditions. Consequently, lower vehicle speeds are expected to translate to reduced crashes along the length of the curves which have presented safety challenges in the past. While the system was initially installed during the summer of 2002, it did not reliably operate in the manner envisioned by Caltrans and required an extensive rebuild, which began during the spring of 2006. The rebuild and subsequent testing and validation of the system required a significant amount of time. As a result, the ICWS was not considered fully operational and reliable until the winter season of 2008-2009. The work presented in this report has evaluated the performance of the ICWS following the rebuild, focusing on the metrics of speed reduction under various conditions and safety performance through crash reduction. In addition, a review of literature pertaining to road condition warning systems was made, along with documentation of winter maintenance, intelligent transportation systems (ITS) engineering and California Highway Patrol (CHP) perspectives of the ICWS.


  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; References; Tables;
  • Pagination: 71p

Subject/Index Terms

Filing Info

  • Accession Number: 01717818
  • Record Type: Publication
  • Source Agency: UC Berkeley Transportation Library
  • Created Date: Jun 11 2019 4:55PM