Development and evaluation of a Driving Observation Schedule (DOS) to study everyday driving performance of older drivers

This paper describes the development and evaluation of an on-road procedure, the Driving Observation Schedule (DOS), for monitoring individual driving behavior. DOS was developed for use in the Candrive/Ozcandrive five-year prospective study of older drivers. Key features included observations in drivers' own vehicles, in familiar environments chosen by the driver, with start/end points at their own homes. Participants were 33 drivers aged 75+ years, who drove their selected route with observations recorded during intersection negotiation, lane-changing, merging, low speed maneuvers and maneuver-free driving. Driving behaviors were scored by a specialist occupational therapy driving assessor and another trained observer. Drivers also completed a post-drive survey about the acceptability of DOS. Vehicle position, speed, distance and specific roadways traveled were recorded by an in-vehicle device installed in the participant's vehicle; this device was also used to monitor participants' driving over several months, allowing comparison of DOS trips with their everyday driving. Inter-rater reliability and DOS feasibility, acceptability and ecological validity are reported here. On average, drivers completed the DOS trip in 30.48min (SD=7.99). Inter-rater reliability measures indicated strong agreement between the trained and the expert observers: intra-class correlations (ICC)=0.905, CI 95% 0.747-0.965, p Language: en