The components included in an on-road assessment will depend on the specific target group of older adults to be assessed and the intended purpose of the evaluation. Many different approaches are reflected in the literature and some well-developed standardized measures are available, though none are generally accepted as the “gold standard”. The key features to be considered in designing or evaluating an on-road assessment procedure relate to course design (e.g., location of assessment, duration of testing, and route characteristics), and driving behaviors and scoring of driving errors (e.g., raters, subjective and objective measures). The characteristics of the route (e.g., four-way stop intersections, yield situations, merge situations) will necessarily influence the driving behaviors elicited and scored to determine the outcome of the assessment (e.g., pass/fail). The scoring mechanisms can be subjective ratings involving observation and some degree of judgment on the part of the examiner, or objective measurements, derived from instruments that record various aspects of driving behavior such as Global Positioning Systems, video-cameras, sensors, accelerometers, computers, and radar and video lane tracking systems. Other important considerations, when designing or evaluating older driver assessment procedures, include retraining and embedding on-road assessment within a broader comprehensive evaluation of driver safety.
