DESIGN CONSISTENCY AND DRIVER ERROR

Geometric design consistency appears to be a major factor affecting accident rates on rural highways, yet little assistance that enables engineers to design roadways consistent with driver expectations is available. AASHTO instead focuses primarily on individual elements, basing guidelines on functional classification, volume, and design speed. The methods that have been presented in the literature for quantitatively assessing design consistency are focused in two primary directions, speed consistency and driver workload. Speed consistency consists of analyzing predicted speeds on a highway and striving to keep those speeds within a narrow range. Several major research studies have provided methodologies for deriving and analyzing predicted speeds. Workload consistency for geometric design, however, has been the focus of only one major research study, receiving an examination by Messer et al. in 1981. In their study they developed procedures that assign subjective workload ratings for features along the roadway, depending on the type and severity of features, the sequence of features, and the proximity to other features. Some 19 rural two-lane highways in Texas were analyzed to derive relationships between the workload ratings provided by the procedure of Messer et al. and the accident records on those roadways. It was concluded that roadway sections with either high workload magnitudes or large positive changes in workload were associated with high accident rates when compared with accident rates on other sections on the study roadways. A final conclusion was that the driver workload procedure of Messer et al. represents a viable tool for use in the examination of design consistency.

Language

  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 148-155
  • Monograph Title: Cross section and alinement design issues
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00675341
  • Record Type: Publication
  • ISBN: 0309060516
  • Files: TRIS, TRB, ATRI
  • Created Date: Mar 20 1995 12:00AM