01551757

Component

Crashes along roadway curves occur frequently. Common countermeasures for these crashes, such as advisory speed signs, are often ineffective, however. A novel approach to curve delineation based on Gestalt perceptual psychology was tested with the aim of reducing vehicle speeds in roadway curves. The Ponzo illusion occurs when two or more objects of the same angular size are presented in a picture at different locations in visual perspective. Displacing an object upward in the picture relative to the others in the visual field makes it appear larger because it seems further away. Increasing the physical size of a distant object relative to a smaller, otherwise identical object in a real-world environment should make the distant object appear closer. Based upon this logical extension of the Ponzo illusion (the "Ponzo scheme" of the title, coined the "Oznop" illusion), strategically locating incrementally-larger chevrons along a roadway curve should make it appear to have a smaller radius, perceptually inducing drivers to lower their speeds in roadway curves. In a closed-road study, subjects approached a curve more slowly, and judged it as sharper, when Oznop-illusion chevrons were used than when equally-sized chevrons were used. In a subsequent study conducted using equally-sized and Oznop-illusion chevrons along two real-world curves, curve entry speeds were lower with the Oznop-illusion chevrons; the differential effect was larger at night. The authors hypothesize that since driver perception is directly affected, Oznop-illusion chevrons should consistently reduce speeds along hazardous curves, thereby potentially reducing the likelihood of crashes at these locations.

This paper was sponsored by TRB committee AHB50 Traffic Control Devices.

01550057

15-1790

English

8p

2015

Transportation Research Board 94th Annual Meeting

Digital/other

Figures; Photos; References

Countermeasures; Highway curves; Highway safety; Operating speed; Visual perception

Chevron markings; Optical illusions

Highways; Safety and Human Factors; I73: Traffic Control; I82: Accidents and Transport Infrastructure

Transportation Research Board Annual Meeting 2015 Paper #15-1790

TRIS, TRB, ATRI

Dec 30 2014 12:39PM