|Date added||July 10, 2018|
|Category||2018 CARSP XXVIII Victoria|
|Tags||Research and Evaluation, Session 4B|
|Author/Auteur||Ma, Haya, Byrne|
|Stream/Volet||Research and Evaluation|
Senior Ontarians aged 80 and over are a rapidly growing segment of the licensed driver population. The number of licenced drivers in Ontario are expected to nearly triple by 2040. The effect of aging on driving is complex and variable. Therefore, maintaining an appropriate balance between senior mobility and road safety requires an objective and valid process to assess driving ability.
In the spring of 2014, Ontario introduced an in-class screening component (ICSC) as part of a Senior Driver Licence Renewal Program (SDRP). Along with the 2 ICSC's, a decision tree was also introduced which would determine, based on a combination of results from the ICSC and the driver record, whether senior drivers are eligible for immediate licence renewal, required to pass a road test prior to renewal or referred to a physician for medical review. The ICSC consists of two brief pencil-and-paper assessments of a person's cognitive capabilities relevant to driving; specifically the "Clock Drawing Test" (to assess visual spatial ability) and the "Letter Cancellation Test" (to assess aspects of visual attention). An evaluation of the SDRP is being conducted to determine the impact of the introduction of the ICSC, the decision tree, and current road test on safety outcomes of senior drivers in Ontario. We will evaluate the 2014 policy changes using a comprehensive dataset of ICSC scores for all seniors who completed the ICSC, road test information for those who were referred to a road test and road safety outcomes (i.e. collisions). Multiple analyses are underway. To determine the discriminant ability of the ISCS, the collision risk history of drivers immediately prior to ISCS administration will be compared between drivers who are deemed eligible for immediate renewal and those who were referred for further screening. As a step further, to determine whether the ISCS is better at selecting only safer drivers for immediate renewal, we will compare the observed collision culpability ratios between drivers who passed the ISCS and a projection line representing the collision culpability ratio that would have been expected in the absence of 2014 changes. The prediction will be derived from the pattern of at-fault to not at-fault collisions for all age groups from a time period preceding the study period and at-fault to not at-fault collisions for age groups up to 80 for the study period. Similar analyses will be done to determine the effectiveness of the road test. Finally, the association between ISCS raw scores and collision outcomes will be explored in a multilevel model and the overall effect of SDRP changes will be determined in a differences-in-differences analysis. Analyses are underway. The results will inform whether and to what extent the introduction of ICSC was effective in identifying senior drivers who may no longer be fit to drive. The analysis will also determine the relative effectiveness of other components of the senior driver licence renewal program, such as the road test that some senior drivers may be required to perform after completing the ICSC. The findings of this study will help to identify future policy directions aimed at improving road safety outcomes of senior drivers.