A cost-benefit analysis of risk-reduction strategies targeted at older drivers

The risk of motor-vehicle collisions increases as driving-related functional abilities decline. These declines can accompany normal or pathological aging and can be identified through driving-related functional screening exams upon license renewal. The objective of this cost-benefit analysis was to determine the utility of four functional screening procedures used to identify drivers at risk for motor-vehicle collisions, as well as an intervention designed to maintain or improve functional abilities. Additionally, this study sought to determine the expected cost per driver if an intervention was designed to target only those drivers who failed the functional ability-based driving screen, versus the expected cost per driver if the intervention was distributed en masse to all drivers 75 years and older. Improving functional abilities in older adults has potential far-reaching health and financial impacts which are broader than their impact of maintaining mobility.

A decision tree was constructed to evaluate the expected costs and benefits of (a) screening all drivers and intervening when indicated (several screening batteries of varying length were considered), (b) no screening, but intervening with all drivers of older age, or (c) neither screening nor intervening (i.e., re-licensing per usual). Test characteristics and risk probabilities were based on a cohort of drivers aged 75 and older from a previous study (Ball et al., 2006). Relevant sensitivity analyses were conducted.

Providing all drivers with the speed-of-processing intervention is the most cost-beneficial option (expected cost per driver = $493.30), even if the cost of the intervention doubles. Sensitivity analysis indicated the effectiveness of the intervention could drop from 86% to 25% and the preventative approach of intervening with all drivers remains the most cost-beneficial strategy. The least cost-beneficial option is almost always re-licensing per usual (expected cost per driver = $1,562.84).

Screening drivers upon license renewal is not currently beneficial because the available technology cannot consistently identify drivers at risk for a collision. However, the speed-of-processing intervention has demonstrated efficacy in improving driving competence (Roenker et al., 2003) and is a non-invasive, moderate-cost intervention that has the potential to protect the safety and mobility, as well as the financial interests, of older drivers and the community at large.