PURPOSE. To study the relationships between the reduction of the useful visual field, age, and driving performance. METHODS. Forty-eight subjects, aged from 23 to 77 years performed a test to evaluate the size of their useful visual fields. The test involved the detection and localization of peripheral signals that could appear in an area of 70° of visual angle. The subjects then performed a simulated car-driving task involving the management of a situation that could lead to an accident. RESULTS. The analysis of the data revealed that the ability to process peripheral signals and simulated driving performance (vehicle speed) deteriorate with age. Simulated driving performance and useful visual field measurement have been analyzed jointly. The results indicate that the reduction of the useful visual field, estimated using a target-localization task, is related to the individual's ability to manage the simulated driving situation (correlation coefficient with speed0.43 and with reaction time for avoidance of a mobile obstacle~0.30) and the deterioration of the useful visual field estimated using a target detection task is related only to vehicle speed (correlation coefficient 0.32). CONCLUSIONS. The adoption of a lower speed by the drivers with a reduced visual field (the elderly ones) is probably an adaptation strategy to process the peripheral information. All useful visual field measurements do not seem to be equivalent to estimate the ability to process information relative to the mobile obstacle. The risk of collision should be estimated only with a useful visual field test using a target localization task.