Development of a weighted scoring system for the Electronic Driving Observation Schedule (eDOS)

The electronic Driving Observation Schedule (eDOS) is a novel approach to assessing older drivers’ performance in their everyday driving environment on their chosen routes. The original eDOS total score is generated using the count of driving errors, which does not account for distinct risk levels of different types of driving errors made in different complexity of driving environments. This study was conducted to create one score to represent the complexity of driving route during each eDOS observation and one weighted eDOS total score to represent older drivers’ performance accounting for the risk of driving errors by their type and the complexity of maneuvers in their corresponding environments. A literature review, a two-round survey with 13 experts in driving evaluation, and iterative discussions between primary investigators were conducted for generating these scores. Two formulae were created to calculate a weighted maneuver/environmental complexity score and a weighted eDOS total score. • An advanced weighted score is created to represent one's on-road driving performance in their everyday driving environment not only using the count of driving errors, but also accounting for the risk level of each error. • The complexity of driving maneuver and environment in each on-road driving trip can be systematically rated.