Effect of task and eccentricity of the target on detection thresholds in mesopic vision: implications for road lighting.
OBJECTIVE
The aim of this work is to assess how adding a driving-related task affects the detection of objects in peripheral vision, under mesopic conditions.


BACKGROUND
The main index used to assess the quality of road lighting installations refers to simple detection tasks in foveal vision, which raises methodological and practical questions.


METHODS
The experimental design consisted of a three-phase experiment. In the first phase, two groups (control and experimental) performed a peripheral detection task (simple task). Based on these results an individual detection threshold was computed for each participant and eccentricity. A tracking task was performed in Phase 2 for both groups (steering a tracking target along a circuit, on a screen). In the third phase, the control group performed the same task as in Phase 2. The experimental group performed a double task, with a tracking (primary) task and a peripheral detection (secondary) task.


RESULTS
The data show an effect of the tracking task and eccentricity on peripheral event detection. The tracking task caused detection performance to decrease from 84.2% to 67.5%, p < .001.


CONCLUSIONS
The small target visibility model used in road lighting may be improved, taking into account the effects of task and eccentricity on target detection.


CONCLUSIONS
This study supports improved roadway lighting design by guiding consideration of sign eccentricity and task load.
Mayeur
Anaïs
A
Laboratoire Central des Ponts et Chaussées, Paris, France.
Brémond
Roland
R
Bastien
J M Christian
JM