Advance warning signals (AWS) provide information warning drivers in advance of the end-of-green interval for an approaching signalized intersection. The purpose of this research was to develop guidelines for the placement of AWS in Utah, both conditions to evaluate the need for AWS installation and guidelines for the AWS system design. The conditions were based on a detailed literature review and were developed using the Policy Delphi method. Six conditions are recommended and discussed in detail, including: limited sight distance, posted speed, isolated intersection, high crash rate, approach grade, and heavy vehicle traffic volume -- Abstract.
Advance warning signals (AWS) provide information warning drivers in advance of the end-of-green phase for an approaching signalized intersection. The purpose of this research was to develop guidelines for the placement of AWS in Utah, both conditions to evaluate the need for AWS installation and guidelines for the AWS system design. The conditions were based on literature of other transportation agencies that had similar AWS systems and were developed using the Policy Delphi method. The Policy Delphi method is the development of a specific policy area through the means of discussion by a committee of experts correlating views and information involving opportunity to react and assess different viewpoints until the committee is in agreement over the policies being recommended. Six conditions are recommended and discussed in detail, including: limited sight distance, posted speed, isolated intersection, high crash rate, approach grade, and heavy vehicle traffic volume. The guidelines for the AWS system design included details about three components: AWS component, advance detection component, and signal timing component. An evaluation matrix was developed by the Policy Delphi method for the purpose of evaluating and prioritizing a group of intersections for AWS installation. A total of 24 intersections were identified by the Utah Department of Transportation for this project that helped to develop and verify the conditions and evaluation matrix. The recommended guidelines and evaluation matrix results are described.
The objective of this study is to evaluate and report the long-term effectiveness of the AWS (Advance Warning System) installed in the state of Utah in June 2005, particularly at the intersection of Bangerter Highway and 13400 South. The results of the study indicate that overall the AWS system has generally had a positive impact on the community, with positive results noted in all areas of analysis. Given the nature of the study, however, it is difficult to quantify the extent of the overall impact as a function of only the AWS system.
Advance warning signals installed upstream of a high-speed signalized intersection (HSSI) warn motorists of impending signal changes in an effort to reduce the frequency of red-light running (RLR) and crashes. The new design utilized an overhead dynamic blank-out sign and flashers. A state-of-the-art Digital Wave RadarTM evaluation system was installed at the study site to collect continuous data of vehicle speeds and RLR events by a non-intrusive method. -- Abstract.
