Evaluation of Ground Mounted Diagrammatic Entrance Ramp Approach Signs

Evaluation of Ground Mounted Diagrammatic Entrance Ramp Approach Signs

Author: Helmut T. Zwahlen

Publisher:

Published: 2000

Total Pages: 174

ISBN-13:

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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.


Evaluation of Ground Mounted Diagrammatic Entrance Ramp Approach Signs

Evaluation of Ground Mounted Diagrammatic Entrance Ramp Approach Signs

Author: Helmut T. Zwahlen

Publisher:

Published: 2006

Total Pages: 2

ISBN-13:

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STATEMENT OF NEED: The effectiveness of ground mounted diagrammatic signs in the context of urban multi-lane arterials leading to a freeway are to be evaluated. This type of guide sign provides much needed information well in advance of the interchange entrance, thus giving drivers more time to change lanes, if needed.


Handbook of Driving Simulation for Engineering, Medicine, and Psychology

Handbook of Driving Simulation for Engineering, Medicine, and Psychology

Author: Donald L. Fisher

Publisher: CRC Press

Published: 2011-04-25

Total Pages: 728

ISBN-13: 1420061011

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Effective use of driving simulators requires considerable technical and methodological skill along with considerable background knowledge. Acquiring the requisite knowledge and skills can be extraordinarily time consuming, yet there has been no single convenient and comprehensive source of information on the driving simulation research being conduc


Roadside Design Guide

Roadside Design Guide

Author: American Association of State Highway and Transportation Officials. Task Force for Roadside Safety

Publisher:

Published: 1989

Total Pages: 560

ISBN-13:

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2010 ADA Standards for Accessible Design

2010 ADA Standards for Accessible Design

Author: Department Justice

Publisher: Createspace Independent Publishing Platform

Published: 2014-10-09

Total Pages: 0

ISBN-13: 9781500783945

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(a) Design and construction. (1) Each facility or part of a facility constructed by, on behalf of, or for the use of a public entity shall be designed and constructed in such manner that the facility or part of the facility is readily accessible to and usable by individuals with disabilities, if the construction was commenced after January 26, 1992. (2) Exception for structural impracticability. (i) Full compliance with the requirements of this section is not required where a public entity can demonstrate that it is structurally impracticable to meet the requirements. Full compliance will be considered structurally impracticable only in those rare circumstances when the unique characteristics of terrain prevent the incorporation of accessibility features. (ii) If full compliance with this section would be structurally impracticable, compliance with this section is required to the extent that it is not structurally impracticable. In that case, any portion of the facility that can be made accessible shall be made accessible to the extent that it is not structurally impracticable. (iii) If providing accessibility in conformance with this section to individuals with certain disabilities (e.g., those who use wheelchairs) would be structurally impracticable, accessibility shall nonetheless be ensured to persons with other types of disabilities, (e.g., those who use crutches or who have sight, hearing, or mental impairments) in accordance with this section.