Evaluation of ground mounted diagrammatic entrance ramp approach signs : final report, October 2000.

Details

• Creators:
  Zwahlen, Helmut T. ; Schnell, Thomas
• Corporate Creators:
  Ohio University. Ohio Research Institute for Transportation and the Environment. Human Factors and Ergonomics Laboratory
• Corporate Contributors:
  Ohio. Dept. of Transportation ; United States. Federal Highway Administration
• Subject/TRT Terms:
  City Traffic--Ohio--Columbus Express Highways--Ohio--Columbus Expressways On Ramps Traffic Signs Traffic Signs And Signals--Ohio--Columbus Traffic Signs And Signals--Research--Ohio
• Publication/ Report Number:
  FHWA/OH-2000/018
• Resource Type:
  Tech Report
• Geographical Coverage:
  Ohio
• Edition:
  Final report.
• Corporate Publisher:
  Ohio Research Institute for Transportation and the Environment. Human Factors and Ergonomics Laboratory
• Abstract:
  Highway-freeway interchanges can be a source of confusion to unfamiliar drivers. Typically, freeway entrance ramp
  
  information is provided by means of trailblazer assemblies (interstate or highway shield, cardinal direction, and a small
  
  white arrow on a blue shield). Trailblazer assemblies are generally located right at the interchange location, giving
  
  unfamiliar drivers very little advance notification as to the proper lane choice needed to gain access to the freeway entrance.
  
  Advance located ground mounted diagrammatic guide signs provide this much needed information well in advance of the
  
  interchange entrance, thus giving drivers more time to change lanes, if needed. Diagrammatic signs have been used in
  
  Europe for many years with great success. The present study investigated the effectiveness of ground mounted diagrammatic
  
  signs in the context of urban multi-lane arterials leading to a freeway. The diagrammatic sign layout was designed as part of
  
  this project in collaboration with ODOT. Six highway-freeway interchanges were selected in the Greater Columbus, Ohio,
  
  area to determine the effectiveness of the diagrammatic signs in the field. Traffic flow video footage was collected at the
  
  selected sites before the diagrammatic signs were installed. The finalized diagrammatic sign designs were then installed and
  
  the traffic flow videotaping was repeated. The collected video footage was automatically analyzed with Mobilizer PC. The
  
  resulting vehicle count, speed, and headway data was used as input to a closed form analytical model to determine the
  
  probability that drivers could successfully change lanes as needed, prior to reaching the gore of the freeway entrance. The
  
  theoretical analysis indicated a much higher probability that an unfamiliar driver could execute a required lane change when
  
  diagrammatic signs are used. ODOT/FHWA evaluators visited the six interchange sites and provided their input and
  
  opinions as to the use of diagrammatic signs. The vast majority of the evaluators fully embraced the idea of diagrammatic
  
  signs. Eye movement recordings were performed at night at the six sites in order to determine if the presence of the
  
  diagrammatic signs was distracting. The results of the eye movement analysis indicate that the diagrammatic signs are not
  
  looked at excessively often or excessively long. The overall median first look distance to the diagrammatic signs was found
  
  to be 125m. An evaluation with unfamiliar test drivers corroborated the findings of the theoretical model analysis, in that
  
  drivers were able to execute a needed lane change much earlier when diagrammatic signs were provided. A set of application
  
  guidelines for diagrammatic signs is provided.
  
  
• Format:
  PDF
• Funding:
  State Job No. 14674(0)
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:c42259e82bbb79f64afcca4c7976770018d635f677cd88923f608cd38d48726a
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/17504/dot_17504_DS1.pdf
• File Type:
  [PDF - 6.95 MB ]