SCREENING AND ASSESSMENT
The most important work on older driver safety that needs to occur in the next five years is on refining screening and assessment tools and getting them into the hands of the users who need them. People who will find the tools useful include medical providers, social services providers, law enforcement personnel, licensing personnel, older drivers, and caregivers.
Screening detects the presence of possible indicators of increased crash risk, such as the presence of slowed walking speed; assessment is the process by which a driver is tested to determine whether a functional limitation influences the person’s ability to drive safely. In the case of the example above, assessment would determine the reasons behind the slow walking speed (e.g., diabetes, arthritis, and muscle weakness) and whether the individual could quickly and accurately move his right foot from an accelerator to a brake pedal.
The state of the art in screening tools is advancing rapidly. A growing body of evidence, first reported in the Model Driver Screening and Evaluation Program from NHTSA and continued by researchers funded by the National Institute on Aging, suggests that divided attention tasks and tasks that require the individual to visualize missing information are the best predictors of prospective crash involvement. These tools focus on cognitive issues.
The understanding and validity of screening tools that detect vision deficits is less clear. Research suggests that screening of contrast sensitivity might be more predictive of crash involvement than screening of visual acuity, though the evidence is mixed. Declines in physical function, absent declines in vision and cognition, can be predictive of increased crash risk, but they are generally amenable to vehicle adaptations and retraining.
There is a great deal of variability in the practice of driver assessment. There is no standard assessment protocol. There appear to be two primary causes for this: client needs and assessor preferences. The category of “client needs” means an assessment can be tailored – and shortened – based on functional deficits the client presents. The “assessor preferences” appear to be based on education and experience, the availability of equipment, and the client’s history with screening tests (the selection of a different test because the client has recently been tested using a particular test, with the goal of eliminating practice effects).
Based on these issues, NHTSA’s efforts will focus on screening and assessment and attempts to standardize within the range and variability of client needs. NHTSA has identified the following steps to take in screening and assessment, and plans to develop a program of research and demonstration projects to address them.