The aim of the project was to develop a method to assess if individuals with visual field loss can drive in a safe manner. The starting point for the project was that the method should be a simulator based method because essentially two criteria were desirable. First, it was important that several events occurred systematically and that events were possible to evaluate, i.e., that it was possible to discriminate between good and bad performances. Second, these events should be the same events for all individuals that was to be tested. The aim was to develop a method that optimizes the validity and reliability with respect to testing of each and one of unique individuals. The testing procedure of the individual level was important because the method would not be used for research purposes but primarily to determine whether a unique individual with visual field loss can drive in a safe manner. Several details that can go wrong during an ordinary experiment, when running subjects, have a minimal impact concerning the experiment because it is most often possible to complement the experimental data collection with another subject. This is not an option for this project.
These criteria and points raised above collectively resulted in the method developed. When an individual completed the scenario developed, a test protocol was generated (after a lot of work). This protocol reveals how the individual performed during the 37 (+2) events (and related measures) based on a safety margin perspective. To support the rater with the assessment of a subject a) data from a reference group (over 100 individuals) and b) a developed test protocol (with critical thresholds for different measurements) were used. The assessment was carried out by two independent raters. If the raters agreed no further judgments were performed. If the raters disagreed a third rater assessed the subjects’ performance. The purpose of the test protocol is that those individuals who want to use the test protocol results as a basis for an exemption application, can do so. It is still the Transport Agency, which decides on an exemption cases.