At nonintersection locations, guidance comes largely from the visual perspective of the road ahead and the location of parallel elements such as lines of trees, fencing, utility poles, parked cars, lighting standards, and bridge rail or guardrail. Traffic control devices are also important, often critically so at night and during other periods of restricted visibility and when speeds are high. For tracking, the driver relies on nearby features; contrasts in color, texture, and shape between pavement and shoulder; curb and barrier edges; and pavement striping. Under high traffic volumes, car following is likely a dominant tracking and guidance aid. The vibration and noise of an inadvertent excursion onto a properly textured shoulder also serve to alert the inattentive driver to potential danger and redirect attention to the tracking task. The purpose of this paper is to identify special difficulties of the older driver in performing these guidance and tracking tasks at nonintersection locations, to determine whether these difficulties can be eased by the installation or enhancement of delineation devices, and to identify conditions in which such installation or enhancement appears warranted. Findings suggest that only minor gains in the safety of older drivers are likely to be realized through the widespread adoption of enhanced delineation techniques. Additional investigation is warranted, however, in 2 areas: 1) the travel and crash patterns of older drivers; and 2) the response of older drivers to a variety of delineation treatments. One promising enhancement for two-lane rural highways having pavement widths of 22 ft or more is to replace standard edgelines with wider, 8-in. ones. Where older drivers make up an unusually large portion of the traffic stream, additional consideration should be given to the incremental enhancement of delineation treatments, either at spot locations or on extended highway segments.

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  • Accession Number: 00489617
  • Record Type: Publication
  • ISBN: 0-309-04664-5
  • Files: TRIS, TRB, ATRI
  • Created Date: Nov 30 1989 12:00AM