Older adults are generally safe drivers, but when compared to experienced, middle-aged adults after controlling for distance driven, they have greater collision risk (see Evans, Reference Evans2004, for a review). Some have asserted that this is a reflection of the “low-mileage bias” (Hakamies-Blomqvist, Raitanen, & O’Neill, Reference Hakamies-Blomqvist, Raitanen and O’Neill2002) and inadequate controls for exposure (Chipman, MacGregor, Smiley, & Lee-Gosselin, Reference Chipman, MacGregor, Smiley and Lee-Gosselin1992). Additionally, because of the increases in age-related medical issues, older drivers are more susceptible to injury and fatalities from collisions (Li, Braver, & Chen, Reference Li, Braver and Chen2003). As the population ages and the presence of older drivers increases in absolute and relative terms, this will become a more important and, admittedly, controversial issue.
Currently, a variety of assessment tools are being evaluated for their effectiveness in determining fitness to drive (Dobbs & Schopflocher, Reference Dobbs and Schopflocher2010; Wood, Horswill, Lacherez, & Anstey, Reference Wood, Horswill, Lacherez and Anstey2013). These tools have relied on identifying factors associated with increased risk of collisions for older adults, including visual abilities, physical strength, and cognitive skill (Ball et al., Reference Ball, Roenker, Bruni, Owsley, Sloane and Ball1991; Ball et al., Reference Ball, Roenker, Wadley, Edwards, Roth and McGwin2006; Meuleners, Harding, Lee, & Legge, Reference Meuleners, Harding, Lee and Legge2006; Rubin, Ng, Bandeen-Roche, Keyl, Freeman, & West, Reference Rubin, Ng, Bandeen-Roche, Keyl, Freeman and West2007; Ross, Cordazzo, & Scialfa, Reference Ross, Cordazzo and Scialfa2014). Tests such as Trails A and B, which assess visual search, memory, and attention, have been found to be moderate predictors of collision risk (Ball et al., Reference Ball, Roenker, Wadley, Edwards, Roth and McGwin2006; Edwards et al., Reference Edwards, Leonard, Lunsman, Dodson, Bradley and Myers2008). As well, brief hazard perception tests (HPTs) have shown a robust and reliable association with safe driving (Horswill & McKenna, Reference Horswill, McKenna, Banbury and Tremblay2004; McKenna & Crick, Reference McKenna and Crick1991; Ross Jones et al., Reference Ross, Cordazzo and Scialfa2014).
Tests of hazard perception assess an individual’s ability to detect and respond to a potentially dangerous element in the roadway before a collision occurs. Assessments within various age groups have revealed that, even after controlling for generally slower responses, older drivers are slower than younger drivers at identifying and responding to dangerous elements (Horswill, Anstey, Hatherly, & Wood, Reference Horswill, Anstey, Hatherly and Wood2010; Horswill et al., Reference Horswill, Mannington, McCullough, Wood, Pachana and McWilliam2008; Scialfa et al., Reference Scialfa, Deschênes, Ference, Boone, Horswill and Wetton2012b). Furthermore, it is a skill that may be improved with training (Chapman, Underwood, & Roberts, Reference Chapman, Underwood and Roberts2002; Fisher, Pollatsek, & Pradhan, Reference Fisher, Pollatsek and Pradhan2006; Horswill, Kemala, Wetton, Scialfa, & Pachana, Reference Horswill, Anstey, Hatherly and Wood2010) and such improvements lead to improved driving safety (Horswill, Taylor, Newnam, Wetton, & Hill, Reference Horswill, Taylor, Newnam, Wetton and Hill2013).
Of particular interest in safe driving is the Useful Field of View (UFOV), a cognitive measure of visual processing speed, which is often assessed under divided attention conditions (Roenker, Cissell, Ball, Wadley, & Edwards, Reference Roenker, Cissell, Ball, Wadley and Edwards2003). The UFOV has demonstrated a moderate relationship to collisions in both retrospective and prospective studies, where those with slower speed of processing have greater collision involvement (Ball & Owsley, Reference Ball and Owsley1993; Ball, Owsley, Sloane, Roenker, & Bruni, Reference Ball, Owsley, Sloane, Roenker and Bruni1993; Goode et al., Reference Goode, Ball, Sloane, Roenker, Roth and Myers1998; Owsley, Ball, Sloane, Roenker, & Bruni, Reference Owsley, Ball, Sloane, Roenker and Bruni1991; Like hazard perception, UFOV performance has demonstrated improvements after training (Ball et al., Reference Ball, Berch, Helmers, Jobe, Leveck and Marsiske2002; Willis et al., Reference Willis, Tennstedt, Marsiske, Ball, Elias and Koepke2006; Roenker, et al., Reference Roenker, Cissell, Ball, Wadley and Edwards2003). As a result, there has been interest in determining if UFOV training in older drivers results in safer driving behaviors and decreased risk of collision.
There also has been some examination of the influence of multiple-object tracking on driving safety among older drivers (Trick, Perl, & Sethi, Reference Trick, Perl and Sethi2005; Lochner & Trick, Reference Lochner and Trick2011). Safe driving requires that one is able to track a number of objects in motion (e.g., vehicles, pedestrians, etc.) while operating the vehicle. However, the number of targets adults are able to track declines with age (Trick et al., Reference Trick, Perl and Sethi2005; Sekuler, McLaughlin, & Yotsumoto, Reference Sekuler, McLaughlin and Yotsumoto2008). It has been suggested that deficits in multiple-object tracking may be related to the increased collision risk in complex driving scenarios such as left turns at intersections (Trick et al., Reference Trick, Perl and Sethi2005). Additionally, multiple-object tracking in older drivers has been found to be predictive of driving performance as determined by an on-road evaluation (Bowers et al., Reference Bowers, Anastasio, Sheldon, O’Connor, Hollis and Howe2013).
A number of training programs have been developed in an effort to improve driving fitness and delay driving cessation in older drivers. Classroom-based training such as the American Automobile Association’s (AAA) and Canadian Automobile Association’s (CAA) Driver 55 Plus target knowledge of changing roadway rules and regulations, driving strategies such as increased shoulder and mirror checks, and information on how aging impacts driving.
In contrast, computer-based programs using cognitive exercises that emphasize speed of processing have also been developed to improve on-road safety. A subset of the sample from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study received speed-of-processing training (Edwards, Delahunt, & Mahncke, Reference Edwards, Delahunt and Mahncke2009). This training progressed over nine sessions and included tasks such as locating and identifying increasingly demanding stimuli. A follow-up after five years revealed fewer state-reported collisions for the training group than the controls. Other longitudinal assessments of cognitive training found that after three years, only nine per cent of those who completed speed-of-processing training had ceased driving compared to 14 per cent of a control group. Similarly, Roenker et al. (Reference Roenker, Cissell, Ball, Wadley and Edwards2003) assessed UFOV training by incorporating three computer-based tasks: central stimulus identification; central and peripheral stimulus identification; and central stimulus identification among distractors. Each participant completed a variable amount of training to reach a threshold of 17 ms for the first task and 75 per cent accuracy for the second and third tasks. Post-training assessments and a follow-up at 18 months revealed that training significantly reduced the UFOV impairment and improved reaction time. However, these improvements were not reflected in behavioral measures during on-road evaluations.
Recently, commercial programs for training skills related to safe driving have been made available to consumers. DriveSharp, developed by Posit Science (https://www.drivesharp.com/), is a cognitive training program marketed for older adults that focuses on UFOV training, multiple-object tracking, working memory, and divided and selective attention. As support for its effectiveness, specifically the UFOV training, DriveSharp cites a number of studies that demonstrate improvements in identification and reaction time (Ball, Edwards, Ross, & McGwin, Reference Ball, Edwards, Ross and McGwin2010; Owsley et al., 1998; Roenker et al., Reference Roenker, Cissell, Ball, Wadley and Edwards2003; Rubin et al., Reference Rubin, Ng, Bandeen-Roche, Keyl, Freeman and West2007; Sims, McGwin, Allman, Ball, & Owsley, Reference Sims, McGwin, Allman, Ball and Owsley2000) and a reduction in risk of collisions up to 50 per cent (Ball et al., Reference Ball, Berch, Helmers, Jobe, Leveck and Marsiske2002).
The program involves three activities: Jewel Diver, Road Tour, and Sweep Seeker. Jewel Diver is intended to improve divided attention by training multiple-object tracking. The game progresses by increasing the speed and number of targets, as well as the similarity between the objects and background. Road Tour focuses on expanding the UFOV by using a double-decision task: while fixating on a central object, participants must discriminate two target objects among distractors in the peripheral field. The game progresses by presenting the objects further in the periphery, increasing similarity between targets and distractors, and increasing the number of distractors in the background. The final exercise, Sweep Seeker, is the speed-of-processing training component. Participants are asked to indicate if two sine-wave gratings are oriented in the same direction. The game progresses by decreasing the allowed decision time. Total training time for each game lasts between two to four hours, and it is recommended that individuals complete 20 minutes of training three times a week until all the games have been completed. However, the marketing and instructions for DriveSharp indicate that “dramatic improvements” in driving safety occur after a minimum of 10 hours of training (Posit Science, 2010, p. 5).
The study discussed in this article assessed the usability and effectiveness of the DriveSharp program for improving the skills trained (i.e., UFOV training, speed of processing, divided attention, multiple-object tracking). We also determined if there was practice-based improvement in performance on tests that are associated with driving safety. The program was assessed with a group of older drivers who completed DriveSharp training for two hours a week over a five-week period in a facilitated environment. Their performance was compared to a control group in pre- and post-training assessments using Trails A and B, and a dynamic HPT.
Methods
Participants
A total of 53 older adults with a current driver’s license were recruited through the Kerby Centre, an older adult activity, education, and resource centre. They were offered in-class, computer-based training to assist with safe driving. Thirty-five of the participants were enrolled in the course; of these, five withdrew before commencement. As well, two individuals could not complete the testing, two missed pre-testing sessions, and another two did not complete the post-test session. Thus, a total of 24 participants (M age = 75.29 yrs, SD = 6.65 yrs) completed both pre- and post-testing sessions in addition to attending the training. The remaining participants volunteered as a part of the control group. Of the 23 who were recruited, five did not complete post-testing. The remaining 18 participants with complete data sets (M age = 68.83 yrs, SD = 6.37 yrs) were included in the analyses. Demographic information is presented in Table 1.
Table 1: Experimental and control group demographic information
* Indicates significant differences between experimental and control group on that measure (p < .05).
MMSE = Mini-Mental State Exam.
Unless otherwise indicated, cell values are arithmetic means (standard deviations).
Although the experimental group was significantly older than controls, the two groups did not differ on other measures. On average, the control group had approximately one more year of formal education. Both groups were in good self-reported physical health, although a minority reported experiencing problems in mental health. Mini-Mental State Exam (MMSE) scores did not differ significantly and indicated that on average they did not demonstrate any obvious signs of cognitive impairment. Their driving history suggested that they were, in a global sense, “safe behind the wheel”.
Materials and Apparatus
Hazard Perception Test
The current version of the Hazard Perception Test uses selected scenes from the dynamic HPT developed by Scialfa et al. (Reference Scialfa, Deschênes, Ference, Boone, Horswill and Wetton2012b), which has good internal consistency and short-term reliability (Scialfa et al., 2014). The test differentiates novice and experienced young adults (Scialfa et al., Reference Scialfa, Deschênes, Ference, Boone, Horswill and Wetton2012b) and experienced young and older adults (Horswill et al., Reference Horswill, Anstey, Hatherly and Wood2010).
Two brief versions of the test lasting approximately 15 minutes each were created. These were used in place of the original HPT, which takes over one hour to complete. A brief version has clear advantages for testing large groups of people. It can be more easily used in a multi-faceted assessment battery without inducing fatigue or taking too much time. This brief version has been shown (Ross et al., Reference Ross, Cordazzo and Scialfa2014) to predict on-road performance in healthy older adults.
Each test comprises a series of 26 silent driving scenes lasting between 10 to 62 seconds filmed in Vancouver, B.C., Canada, and surrounding areas using a Sony Handycam Camcorder, model HDR-SR11 in AVCHD 16M (FH) format at a resolution of 1920 × 1080/60i. The camera was mounted inside a 2005 Subaru Impreza and secured to the inside door window on the passenger side of the vehicle. An extendable arm allowed the videotaped scenes to give a “driver’s eye” view. Filming occurred in March and April, 2009, during daylight hours, generally under clear skies and dry roadway conditions in a variety of frequently encountered environments (e.g., residential, limited-access freeway). Each driving scene was edited from original files using Sony Vegas Movie Studio Platinum software (version 9.0a) at a resolution of 1280 × 720. Only one traffic device found in the scenarios differed from those found in Alberta, a flashing green signal light. Participants were instructed to treat the flashing light as a solid green light. For a detailed description of the types of hazards presented, please see Scialfa et al. (2012a).
Of the 26 driving scenes in each test, 17 (65%) and 18 (69%) respectively contained a traffic conflict, defined as a situation in which the camera car was required to take evasive action such as slowing, stopping, or steering to avoid a collision with a road user or stationary object. Examples of the traffic conflicts include a braking lead vehicle, pedestrian incursion, and construction equipment in the driving lane (see Figure 1). The remaining scenes did not contain a traffic conflict and were included to increase uncertainty about hazard presence, as would be the case in normal driving.
Figure 1: Static screenshot of a traffic conflict scene from the dynamic hazard perception test (Scialfa et al., Reference Scialfa, Deschênes, Ference, Boone, Horswill and Wetton2012b) (resolution is better than depicted)
At onset of the traffic conflict, the object in the scene had a height ranging between 1 and 10 deg (M = 3.0 deg) and a width between 1.6 and 14.8 deg (M = 4.4 deg) at a nominal viewing distance of 50 cm. The eccentricity of the objects relative to screen centre ranged between – - .9 and 3.4 deg on the vertical axis (M = 1.0 deg) and – -16.2 and 10.9 deg on the horizontal axis (M = – -1 deg). Thus, objects in traffic conflicts are quite varied in their size and location but, on average, do not require excellent acuity or peripheral vision.
Custom software defined the onset, offset, and spatial extent of the traffic conflicts of each scene (see Marrington, Horswill, & Wood, Reference Marrington, Horswill and Wood2008). This same software was used to present scenes to participants and record the spatial coordinates of their responses and their reaction times. A 17″ LCD desktop monitor with a resolution of 1280 × 1024 set at a viewing distance of approximately 50 cm was used to present the HPT and collect responses. Participants were instructed to identify the traffic conflict as quickly and accurately as possible using the mouse. The average reaction time to traffic conflict scenes was used as the dependent measure because errors were infrequent.
Trails A and B. These brief, paper-and-pencil tests require that one draw a line correctly connecting a series of numbers (Trails A) or alternating between numbers and letters (Trails B). The test administrator corrects errors during performance, and the time taken for completion is used as the dependent measure. Trails A and B are commonly used in the neuropsychological literature as a measure of processing speed, working memory, and executive control and are also used in commercially available assessment tools for driver risk such as the Roadwise Review (e.g., Scialfa, Ference, Boone, Tay, & Hudson, 2010). To facilitate comparison with our samples, Tombaugh (Reference Tombaugh2004) reports that average Trails A and Trails B completion times for those aged 70–74 are approximately 42 and 109 sec respectively.
DriveSharp
Participants completed the DriveSharp training sessions in a classroom environment on individual desktop computers. During the first session, the program included a brief tutorial for each exercise and prompted participants to complete an initial baseline assessment. After this, the program automatically prompted them to complete further assessments when a variable number of trials had been completed, unless a participant actively selected an assessment to be done. Each of the games progressed based on the improvement of the individual. The algorithms used to determine progress are not freely available, but Dobres et al. (Reference Dobres, Potter, Reimer, Mehler, Mehler and Coughlin2013) have reported that the programs use a staircase to adjust the difficulty of the task, converging on a 70.7 per cent correct performance criterion. There are three exercises (see Figure 2).
Figure 2: A. Screenshot of the DriveSharp Jewel Diver activity (on-screen resolution is better than depicted). B. Screenshot of the DriveSharp Road Tour activity (on-screen resolution is better than depicted). C. Screenshot of the DriveSharp Sweep Seeker activity (on-screen resolution is better than depicted)
Jewel Diver incorporates divided attention and multiple-object tracking. Participants are shown a number of targets (jewels), which are then masked (by bubbles). The goal is to track the bubbles as they move around the screen and identify which occlude the target jewels. Similarly, the assessment requires that participants track jewels occluded by fish. Improvement scores are based on the average number of jewels correctly tracked.
Road Tour is intended to enlarge the UFOV. Participants focus on the centre of the screen and are briefly shown a target vehicle. They must then identify which vehicle they saw at the centre of the screen as well as indicate the location of a secondary target (a traffic sign) in their periphery. Improvement is operationalized as the average exposure duration of the target stimuli when it is correctly identified, in conjunction with the correct localization of the peripheral stimuli.
Sweep Seeker trains speed of processing by asking participants to identify the orientation of sine-wave gratings that vary in contrast and spatial frequency. During the game, participants are shown a series of tiles. They must select three matching tiles to clear the tiles from the screen. After clearing a selection of tiles, a window that displays two gratings is shown. Participants are asked to identify the movement of the gratings (i.e., inward or outward optic flow). Responses are timed, and a score is obtained from the speed with which they determine the orientation. After completing the task, they are returned to the original “tile-breaking” task. The goal is to clear the screen of all the tiles. The assessment requires that participants only determine the orientation of the gratings. Improvements are tracked by averaging the exposure duration of iterations where the participant successfully indicated the direction of the sine-wave gratings.
Usability Assessment
The primary outcome variables in this study were those related to the DriveSharp exercises (e.g., time spent on them and performance improvement), in addition to response times for Trails A, Trails B, and the Hazard Perception Test. While this information provides insight into the behavioral changes that occurred as a result of the DriveSharp training modules, it does not assess participants’ general opinions and beliefs regarding the usability of the program. Effective adoption of a technology-based training program requires that the target audience is able to use the technology. People are more likely to discontinue a less usable training program before they reach the recommended training times, and, as a result, any potential improvements to driving would be reduced. Additionally, ease of use is especially important for a program directed towards older adults, who may have lower computer literacy (Nielsen, Reference Nielsen2013).
To gather usability data, participants completed a brief, 20-statement survey (See Table 2). The statements were either positive or negative remarks about the program, training routine, or computers in general. A 5-point Likert scale, with 1 representing “strongly disagree” and 5 representing “strongly agree” was used.
Table 2: Responses to usability questions regarding the DriveSharp training software
Procedure
In addition to the training described in the discussion herein, there were two experimental sessions lasting approximately one hour each. During the pre-testing session, participants completed a demographic questionnaire assessing collision history, annual distance driven, and information regarding any medical issues that may affect their driving. Additionally, the MMSE (Folstein, Folstein, & McHugh, Reference Folstein, Folstein and McHugh1975) was administered to assess their cognitive status. Participants also completed Trails A, Trails B, and an HPT.
For the HPT, to ensure that all participants were familiar with using a computer mouse, a practice screen was displayed. The practice screen contained a series of 10 targets; participants were asked to select each target using the mouse. After familiarization, they were instructed on how to complete the hazard perception test. They were given a short practice trial of eight scenes to familiarize themselves with the test requirements. Traffic conflicts similar to those occurring during the experimental trials were used.
The DriveSharp course lasted five weeks, during which participants were scheduled to attend two one-hour sessions a week for a total of 10 hours of training. Sessions were led by a facilitator who assisted with the initial introduction to the program and any difficulties operating the computer. Participants were instructed to follow the recommended schedule for the DriveSharp software as much as possible, however, as the sessions were longer than the recommended 20 min, they were free to select the exercises on which they would focus. As such, there was considerable variability in the exercises they chose to complete.
After completing the five weeks of training, participants attended a post-testing session where they completed a usability questionnaire, Trails A and B, and a second version of the HPT. The majority of participants completed post-testing within one week of ending the DriveSharp training.
With the exception of the usability questionnaire, the protocol was the same for the control group’s pre- and post-testing sessions, including the five-week interval between testing.
Results
Attendance and Training Times
Posit Science has stated that participants must complete at least 10 hours of training for the program to have an effect on driving behaviors (Posit Science, 2010, p. 5). To satisfy this requirement we scheduled 10 one-hour sessions for the participants over a five-week period. The average attendance of the participants who were post-tested was M = 9.43 sessions (this includes two participants from the first course attendees who attended 11 sessions).
Although the participants were scheduled for 10 hours of training time, the average time spent specifically on the training component of the DriveSharp program was only M = 4.2 hrs., SD = 1.45 (Table 3). This is less than one half the time recommended. Additionally, some participants had zero training hours logged for some of the games. Training times of zero do not indicate that participants had no experience with the task; due to misunderstandings during the training sessions, a number of participants spent their time completing assessments instead of the training exercises.
Table 3: Training times in minutes
Learning as Shown by Assessments
The number of assessments varied greatly for each exercise: Sweep Seeker (M = 3.17, SD = 1.56), Jewel Diver (M = 2.67, SD = 1.2), and Road Tour (M = 2.71, SD = 1.3). When using recommended scheduling, DriveSharp indicated that after a participant completed a given level of training, the program would prompt them for an assessment. However, as participants’ training sessions lasted longer than 20 minutes, they were free to select not only the exercises but also additional assessments. To determine if the number of assessments related to performance at the individual level, the percentage improvement (from baseline raw scores) for each exercise was modeled in relation to the number of assessments (see Figure 3).
Figure 3: A. Per cent improvement of participants for each assessment of Jewel Diver performance. B. Per cent improvement of participants for each assessment of Road Tour performance. C. Per cent improvement of participants for each assessment of Sweep Seeker performance. Participants vary on the number of assessments they took. DriveSharp did not report the exact value if a per cent improvement was less than zero (these values are recorded and displayed as a “zero” improvement).
These data demonstrate that the participants varied greatly in the number of assessments taken, and improvements are quite variable both across and within individuals. Road Tour and Jewel Diver appear to have a general linear trend indicating further improvement beyond the first assessment. Although it seems natural to predict that participants would improve more with each assessment because they had received more training between assessments, such an assumption would be inappropriate. As we have noted, it is possible that no training at all occurred between a participant’s assessments. Recurrent exposure to an assessment would presumably lead to some improvements, but these improvements are likely to be less robust than if the participant spent time training between assessments.
That being said, to determine if there was a significant improvement in performance, separate repeated-measures analyses of variance (ANOVAs) were conducted to analyse the per cent improvement for the first three assessments. Performance during only the first three assessments was used as these cells were the most populated; only 40 per cent of participants completed a fourth assessment for the Sweep Seeker game, and only 21 per cent for both Jewel Diver and Road Tour. Only data from participants who had completed all three assessments were used. The Greenhouse-Geisser correction was used where sphericity was violated.
Descriptive statistics for each analysis are presented in Table 4. Analysis of the Sweep Seeker game indicated there was no significant improvement in performance, F (2, 32) = 1.63, p = .213, ηeta 2= .092. Analysis of Jewel Diver data (n = 15) indicated significant improvement – F (1.29, 18.06) = 4.11, p = .049, ηeta 2 = .227 – and a significant linear trend, F (1,14) = 4.78, p = .046, ηeta 2 = .254. Finally, analysis of Road Tour assessments (n = 10) was non-significant, F (1.17,10.48) = 1.43, p = .266, ηeta 2 = .137. Thus, there is no strong evidence of improvement with time on task, even though the time spent was not unambiguously associated with training, as opposed to assessments.
Table 4: Descriptive statistics for the analysis of performance improvement (%)
Analysis of Outcome Variables
If DriveSharp training is beneficial for skills related to driving safety, then one would expect the experimental group to show improvement in HPT latencies, as well as performance on Trails A and B, two tests that are associated with driving safety. Furthermore, if this improvement in post-test outcome variables is the result of training, and not merely an artifact of practice on the outcome variables, then the experimental group should demonstrate greater gains than the control group. In order to assess this, we compared the experimental and control groups in their pre-test versus post-test differences on the HPT, Trails A and Trails B.
Only those with complete data sets were included in the analysis; participants with results missing from either pre- or post-testing were excluded. One participant was removed from the experimental group because their pre-test HPT scores were over 3 standard deviations greater than the sample average (23 s. vs. 3.55 s.). The final analysis included n = 23 participants from the experimental group and n = 18 from the control group. Analyses of the Hazard Perception Test were completed using reaction time for the scenes containing a traffic conflict.
Pre-Test Group Differences
A comparison of the pre-test assessments (Trails A, Trails B, and the HPT) was conducted to examine what group differences, if any, existed at baseline. The descriptive statistics and significance tests for the pre-test analyses are displayed in Table 5. The analyses indicated that the control and the experimental group differed significantly on their pre-test scores for Trails A (t[40] = 2.02, p = .050), Trails B (t[40] = 2.59, p = .013), and the HPT (t[40] = 2.96, p = .005). The experimental group demonstrated slower performance than the control group on all tests. As a consequence, there is a need to control for these pre-test differences while assessing post-test differences in performance.
Table 5: Pre- and post-test experimental and control group performance on Trails A, B, and HPT
* Indicates significant difference between experimental and control group on that measure (p < .05).
Post-Test Group Differences
The descriptive statistics and significance tests for the post-test analyses are found in Table 5. The analysis indicated that there was no significant difference between the control and the experimental groups’ Trails A test results (t[40] = 1.17, p =.249). However, there was a significant group difference on Trails B (t[28.37] = 2.17, p =.039) and the HPT (t[31.47] = 2.29, p =.028), where the experimental group demonstrated slower performance.
A comparison of pre-test and post-test data indicates that both groups demonstrated improved speed on all outcome variables, as might be expected from practice effects alone. However if the DriveSharp training influenced performance as expected, the experimental group should reveal significantly greater post-test improvements.
Gain Score Analysis
To account for both practice effects and the slower pre-test scores for the experimental group, we conducted a third test, an examination of the difference between pre-test and post-test scores. This test, referred to as gain score analysis, determined if the rate of learning was equivalent between groups. If DriveSharp does have an effect on performance, then we would expect to see a larger change for the experimental than the control group.
Descriptive statistics and significance values are shown in Table 6. Analyses revealed that were no differences in the rate of learning for Trails A, Trails B, or the HPT. The mean gain scores on both Trails A and B indicate that the experimental group had greater average improvement; however, there was considerable variance around these scores as well. The mean change in the HPT performance revealed a trend contrary to expectations, in that the control group showed greater gains.
Table 6: Gain score (pre- and post-test) values for experimental and control group performance on Trails A, B, and HPT
Note: Cell values are arithmetic means and standard deviations.
* Indicates significant difference between experimental and control group on that measure (p < .05).
HPT = hazard perception test.
MMSE = Mini-Mental State Exam.
Because the groups differed on age at testing, an analysis was carried out on gain scores using age as a co-variate. Descriptive statistics and significance values are provided in Table 6. After adjusting for the group differences due to age, there was a non-significant trend towards greater improvement in the experimental group. However, in no case were the group differences significant. We also adjusted for individual differences in age, MMSE score, and number of collisions within the past two years (see Table 5). Again, no significant group differences were found.
Training Times and Trails A, B, and HPT Gain Scores
If the DriveSharp program produces improvements in skills related to safe driving, then one would expect those who spend more time in the exercises to show the greatest gains in driving-related skills. To examine this hypothesis, we evaluated the relationship between the time spent training on each DriveSharp game and the difference scores from pre-test to post-test (i.e., gain scores) for Trails A, Trails B, and the HPT.
Regression analyses revealed that there was no significant relationship between time spent training on the Sweep Seeker component for either Trails A gain scores (F[1, 22] = .01, p = .911), Trails B gain (F[1, 22] = .94, p = .342), or HPT gain (F[1, 22] = .66, p =.425); the Jewel Diver component for Trails A (F[1, 22] = .00, p = .990), Trails B (F[1, 22] = .33, p =.574), or the HPT (F[1, 22] = .38, p =.544); or the Road Tour component for Trails A(F[1, 22] = .01, p =.921), Trails B (F[1,22] = 1.37, p = .253), or the HPT(F[1, 22] = .837, p = .370). Additionally, there was no relationship between total time spent training and either Trails A gain scores (F[1, 22] = .00, p = .993), Trails B gain (F[1,22] = .00, p = .998), or the HPT gain (F[1,22] = .851, p = .366). These findings indicate that neither the time participants spent training on each component of DriveSharp, nor the total time training, were significantly related to their improvement scores.
Usability
Responses to the usability questionnaire are provided in Table 2. Generally, respondents found the system easy to use and believed it was not unnecessarily complex. They also understood how it would improve their driving skills and would recommend it to a friend. Participants believed most people would learn the system quickly and that the registration process was not difficult. However, most users would not buy this program nor would they be likely to use the program again.
On a per game basis, respondents believed that they understood how to play Sweep Seeker and Jewel Diver, while Road Tour was more difficult. They felt that they understood the difference between “assessment” and “training” steps, and they knew how to pause the games if needed.
It is important to note (see the range statistics in Table 2) that there was considerable variability in the responses given to these usability questions. Some participants were quite positive in their evaluations, while others were very negative. This variability indicates that experiences with the program are person-specific, and it is likely that compliance and effectiveness will depend on the match between the demands of the software and the capabilities of the user.
Self-reports are not necessarily accurate. Answers may be exaggerated, omitted because a respondent is embarrassed, or inaccurate because of forgotten details. For example, results from the usability questionnaire indicated that the participants believed they understood the difference between assessment and training, but their data demonstrate fairly clearly that this was not the case, as they took, on average, many more assessments than requested. This does not mean that the usability data have no value. Regardless of level of true comprehension, the self-perception of comprehension is necessary for user acceptance.
Discussion
Usability assessments of the program indicated that participants rated the training experience favorably, and that they believed it had a positive effect on their driving behaviors. However, analyses of performance data did not reveal any significant benefits to the exercises. After adjusting for group differences due to age, MMSE scores and number of collisions within the past two years, we found that – although there was a trend towards greater improvement in the experimental group – effects sizes remained low, and the difference was still non-significant (see Table 6). Additionally, although there was significant improvement in Jewel Diver from baseline to the third assessment, neither the time participants spent training on each component of DriveSharp, nor the total time training, was significantly related to their improvement scores.
Non-random assignment and variability in training times are both challenges to interpreting the results of the study. Participants contacted the centre specifically either to register for the DriveSharp program or to volunteer as part of the control group. They may have self-selected such that only those who felt that they were most in need of training agreed to join the training group. This self-selection may have worked against any demonstration of improvement. However, if the training group was “extreme”, then they should have shown more improvement, if only as an artifact of “regression towards the mean”. Second, in applied settings, it is very likely that those who feel themselves to be most in need of training will be more likely to enroll in training programs. Thus, the present results reflect the realities of training efforts for driver improvement.
Additionally, training times, which were an average of 4.2 hours, are problematic as any driving skills the program may improve are indicated to be a result of receiving a minimum of 10 hours of training. However, it is noteworthy that other studies of skill training (e.g., Horswill et al., Reference Horswill, Anstey, Hatherly and Wood2010; Roenker et al., Reference Roenker, Cissell, Ball, Wadley and Edwards2003) reported improvements in performance after much shorter periods of time. In fact, Roenker et al. (Reference Roenker, Cissell, Ball, Wadley and Edwards2003) demonstrated that speed-of-processing training of 4.2 hrs on average resulted in significant improvements in on-road driving.
One possibility may be that performance improves over time to some asymptotic level and that improvements in driving skills may be positively related to the amount of time spent completing the exercises. However, although the data from the current study suggests initial improvement from baseline to the first assessment, after this, participants’ improvement leveled off. As noted previously, the amount of training was not consistent between participants. Additionally, it is clear that despite the continual presence of a facilitator, there was considerable variability in time spent training on individual games and, thus, in the total training received. Despite these limitations, the findings of this study are consistent with other assessments of DriveSharp’s impact on driving performance (Dobres et al., Reference Dobres, Potter, Reimer, Mehler, Mehler and Coughlin2013).
From some initial pilot testing, it appeared that DriveSharp was designed to require participants to complete a certain amount of training for each game. It was possible, however, for participants to play whichever game they chose. This is likely the cause of the low (in some cases non-existent) training times observed for some of the games. However, it does not account for the low overall training times observed. One possible explanation is that there is invariably a certain amount of time spent at the start of each class to turn on the computers, discuss the program, and converse about other topics. During a post-testing session, one participant reported 20 minutes on average per class to begin training, leaving only 40 minutes for the exercises themselves.
It is also worth noting that total training time as recorded by the software is only a reflection of time spent with the exercises; time spent in “assessment” sessions is not recorded. Some participants completed as many as eight assessments of one game, and assessments can be quite lengthy. However, when reporting individual results, DriveSharp records and reports on a maximum of six assessments. Assessments are important to provide an evaluation of progress; however, they should not be substituted for training sessions as their design features and practice benefits likely differ from the training sessions. For future DriveSharp studies, we recommend limiting the number of assessments to three per game – one at the beginning, one halfway through the course, and one at the termination.
Although the usability data reflect a generally positive attitude towards the program, a limitation in their interpretation is participant attrition. There were six participants who dropped out from the DriveSharp experimental group, and we were unable to obtain usability data from these individuals. Anecdotally, some of those individuals dropped out because they found the program too difficult and/or they did not understand how it would improve their driving. As DriveSharp assesses performance from mouse speed and accuracy calculations, individuals with no previous computer experience are at a disadvantage compared to those comfortable with the technology.
Clearly then, DriveSharp faces challenges regarding compliance, usability, and effectiveness. The compliance and usability problems our study uncovered have implications for implementation of the exercises. If it is difficult in a facilitated setting to ensure that participants understand the instructions and comply with them, then how much more difficult will it be if individuals work without a facilitator? Given that more than 10 hours of involvement with the product did not produce meaningful change in performance, how likely is it that older adults, many of whom are not “savvy” with video games, will invest even more time and effort with the programs? Is the time and effort commensurate with gains, or would it be more sensible to have individualized, on-road instruction that focuses on those sub-skills that are most in need of remediation? These questions must be addressed in additional, independent research.
