More than ever, road safety is a public health concern. One cause for this concern arises from changes in demographics. It is expected that the number of older drivers will increase substantially in the next decades. Specifically, it is estimated that this number will double within the next 25 years from 27 million to nearly 60 million in the United States [1
]. With ageing, sensorimotor and cognitive changes are known to reduce driving performance [2
]. A host of changes in the visual system occurs with ageing [3
]. Moreover, some authors suggest that older drivers reduce their visual search patterns which results in a perceptual narrowing (or tunnel effect) [4
]. An in-vehicle study conducted by Bao and Boyle [5
] showed that compared to younger drivers (18-25 and 35-55 years old), the road scanning of older drivers (65-80 years old) at intersections were primarily confined to areas located directly in front of or slightly to the right or left of the vehicle's direction of motion. Similarly, Romoser and Fisher [6
] examined if older drivers made a secondary look as often as younger drivers at the onset of the turn at an intersection. Their results revealed that, while turning, older drivers took less often that second look than younger drivers for potential hazards (6.9% vs. 22.2%, respectively).
Other studies have assessed visual search strategies while changing lanes but did not consider the age effect [7
]. For instance, Kiefer and Hankey [10
] evaluated two groups of drivers (40-50 and 60-70 years old). They reported visual inspections towards the blind spot for only 32 and 15% for the left and right lane changes, respectively. Unfortunately, no specific mention of blind spot inspection made by their older drivers is mentioned. Therefore, there is little information on how older drivers verify blind spot while changing lanes even though it is mentioned that it is a problematic and recurrent issue with older drivers during on-road evaluation [11
]. In a simulator experiment, Lavallière et al. [13
] showed that older drivers inspected their blind spot less frequently than younger drivers while changing lanes (41% vs. 86%, respectively). An important question that remains is whether or not older drivers will show similar frequency of visual inspections towards the blind spot on the road and if training could help improving older drivers' visual search strategies in such situations.
Several retraining programs adapted to older drivers have been developed and are now proposed to this category of drivers. These programs are mostly classroom oriented (refresher program) and aim at promoting safe driving as well as increasing older drivers' confidence behind the wheel through a curriculum emphasizing awareness of traffic hazards, insisting on the need for anticipating the actions of other drivers and providing a general overview of traffic regulations. There are suggestions, however, that these refresher programs do not reduce crash occurrences [14
] and do not modify older drivers behaviors. In a cohort of 884 older drivers (55 to 94 years old) who attended a classroom program, Nasvadi and Vavrik [15
] found no significant decrease in crash rates in any age group. This might not come as a surprise because motor learning occurs as a direct result of active practice and concrete feedback on the motor performance. As suggested by many authors, physical practice is the preferred form of practice for optimizing learning [16
]. Accordingly, several aspects of driving may not be optimized in conventional classroom oriented programs as learning general driving information does not result in sufficient modification to sensorimotor driving strategies. If inadequate visual search precedes a driving error, corrective feedback for this specific action and practice are needed if a decrease of such errors is to be achieved. The development of an effective and specific error-detection process likely translates into sensorimotor strategies related to driving. This key concept is often defined as transfer-appropriate practice [17
In a recent study, Bédard et al. [18
] measured knowledge of safe driving practices and driving performance before and after a training program (intervention group) combining a refresher course and on-road training (two 30- to 40-minute on-road practice sessions with a certified instructor). Compared to a control group (no intervention), participants in the intervention group improved their driving knowledge (measured through the 55ALIVE Driver Safety Program questionnaire) as well as some aspects of on-road driving (starting/stopping/backing and moving in the roadway). This study, however, does not allow determining the selective effects of the refresher course and on-road training on the driving improvement. Romoser and Fisher [6
] compared the effectiveness of active, passive and no training on older drivers' performance in intersections. Active training increased a driver's probability of looking for a hazard during a turn by nearly 100% in both post-training simulator and on-road driving sessions. Customized feedback was successful in altering drivers' perception of their abilities. Those receiving passive training (i.e., refresher course only) or no training did not change their visual inspection strategies at intersections. It was found that active training (feedback and practice) was more effective than passive training for increasing older drivers' likelihood of looking for threats before a turn.
In the present study, we evaluated if simulator training, coupled with video-based feedback can modify visual search behaviors of older drivers while changing lanes (Feedback drivers). The results were compared to those of participants in a control group who attended a refresher course and drove the same simulator scenario as the Feedback group without receiving feedback about their driving performance (Control drivers). The effectiveness of the training was assessed by comparing on-road driving performance before (Pre-training) and after (Post-training) the training program using a standardized evaluation procedure to document visual search patterns during lane changes. Based on the motor learning arguments presented above, we hypothesized that, compared to Control drivers, Feedback drivers should increase the frequency of visual inspections towards the blind spot while changing lanes after attending the training program.