Driving among Adolescents with Autism Spectrum Disorder and Attention-Deficit Hyperactivity Disorder

Over the past several decades there has been a surge of research on the contextual, biological, and psychological factors associated with transportation safety in adolescence. However, we know much less about the factors contributing to transportation safety among adolescents who do not follow a typical developmental trajectory. Adolescents with developmental disabilities (DD) such as Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) have a wide range of behavioral and psychological deficits that may make the complex task of driving even more challenging. Because these adolescents often retain characteristic symptoms of their disorder into adulthood, it may impede their ability to achieve important milestones during the developmental transition from adolescent to adult. As the motivating force behind autonomous living and employment, the capacity for independent transportation is paramount to an adolescent’s overall success. This critical review will draw from the current body of literature on adolescent drivers with developmental disabilities to determine (1) areas of impairment; (2) safety risk factors; and (3) effective interventions for improving driving safety in this vulnerable population of adolescent drivers between the ages of 15–22. This review will also identify important unanswered research questions, and summarize the current state of the literature.


Introduction
Developmental disabilities (DD) affect one in six children aged 3 through 17, and are defined as a group of chronic conditions characterized by impairment in physical, learning, language, or behavior areas beginning during development [1].Two of the most common DDs are Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD), which account for approximately half of all DDs [2].These disorders are often accompanied by functional impairments in day-to-day activities including safe transportation and mobility [3].Safely operating a motor vehicle can provide access to important educational, workforce, healthcare, and social opportunities.Equitable access to these societal assets is important for autonomy and connectedness.Driving facilitates mobility, which in turn increases the likelihood of those with DDs being successfully employed, making meaningful relationships, and becoming independent.Although public transportation is frequently used in large cities and urban areas, those with DDs in rural and suburban areas are forced to rely on family and friends for transportation [4].Improving quality of life for individuals with DDs is particularly important, as more and more children are being diagnosed and will later be faced with the challenges of living independently [5].The ability to drive is vital for success in achieving the independent lifestyle desired by the majority of those with DDs [4].
Teenage drivers with DDs, however, are a particularly vulnerable population.ASD and ADHD are unique, in that the impairments associated with the disorders largely impact driving performance rather than driving knowledge [6,7].A variety of impairments make the cognitively demanding task of driving for these individuals even more difficult compared to typically-developing teens [8].For adults with ADHD [9,10] and ASD [11], driving is cited as a skill that can significantly improve or hinder successful transitions into adulthood and overall quality of life.Previous literature suggests that individuals with DDs such as ADHD and ASD take longer to pass the on-road test to obtain independent license [12][13][14].Thus, it is important to understand how to promote safe mobility among adolescents with DDs, who may be most sensitive to the positive and negative aspects that independent driving can offer.In this review, we summarize the literature on what is known about how adolescents diagnosed with ASD and ADHD experience the learning-to-drive process, and highlight some potential challenges of these diagnoses and important unanswered questions relating to this topic.

Method
This critical review included research studies related to ASD and/or ADHD and driving.Each study was evaluated using a validated, 24-item measure of methodologic quality developed by Cho and Bero [15], and assigned a method quality index (MQI) score ranging from 0 to 1, with scores closer to 1 indicating better methodological quality.The MQI score takes various aspects of study methodology into account, such as detail of study methods provided, sample size justification, appropriate statistical analyses, and accurate interpretation of results.All studies reviewed, with the exception of two, had a method quality score of 0.50 or above (M = 0.654; SD = 0.079).Cox and colleagues' study [16] received a score of 0.48 due to relying solely on reports from parents.The study with a method quality score of 0.49 was due to a lack of methodological detail in the final report [17].Table 1 provides an overview of each of the studies reviewed.Method quality scores were not applicable to review papers; therefore, they were not assigned MQI scores.Review studies are summarized at the end of Table 1

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The commentary trained group had fewer crashes, reduced their speed on approach to hazards sooner, and applied pressure to brakes sooner than controls

ASD
One of the fastest-growing neurodevelopmental disabilities in the United States is ASD, with a prevalence that has increased from 1 in 88 children in 2008, to 1 in 68 children in 2014 [18].ASD is characterized by deficits in social communication and social interaction, the presence of repetitive behaviors and restricted interests, and a complex combination of diminished and intact cognitive abilities [19].The majority of these characteristics have been identified and studied in children with ASD, but research suggests that these impairments also persist into adolescence and adulthood; a period in which complex tasks like driving become an essential part of everyday living [20][21][22].
For children diagnosed on the high-functioning end of the Autism Spectrum in the early 2000 s, who will soon be approaching driving age, the decision to drive and the challenges that will accompany this task are approaching quickly [18].Curry and colleagues [23] recently conducted one of the largest studies to date on driver licensure among individuals with ASD.They examined licensure rates and progression through licensure in a sample of approximately 600 New Jersey residents with ASD.They found that approximately one third of individuals with ASD acquired a driver's license, but did so roughly 9 months later than typically-developing individuals.About 90% of those individuals with ASD who obtained a learner's permit also obtained a license within the next two years.This points to a discrepancy in the number of individuals with ASD who are interested in/planning on driving (approximately two thirds) [7] and the current licensure rates in this population [23].There is however, little research to explain why this may be the case.Despite the limited number of individuals with ASD who are licensed and driving, and the importance of driving in increasing independence and quality of life, research in transportation safety among drivers with ASD is sparse.Although many of the impairments associated with ASD may negatively impact safe driving in this population, the most commonly-cited issues by parents, caregivers, and driving instructors relate to three general areas of impairment: anxiety, processing speed and executive function.

Anxiety
Previous survey data have identified anxiety as one of the most commonly reported driving barriers for individuals with ASD [12,16].Anxiety disorder presents as a disproportionate fear or adverse reaction to relatively nonthreatening environmental stimuli, and is a common co-morbid condition seen in individuals with ASD [24,25].Although prevalence rates of anxiety disorders in the ASD population have been varied, ranging from 47 to 84% [25,26], several studies have found higher rates of clinical and subclinical levels of anxiety in individuals with ASD as compared to typically-developing groups [26][27][28].Within the population of individuals with ASD, it has also been found that individuals with High-Functioning Autism (HFA) or Asperger's Syndrome (AS) exhibit particularly high levels of anxiety [26,27].It has been suggested that this is due to the highly cognitive nature of anxiety disorders; therefore, individuals on the Autism Spectrum with higher IQ may experience greater levels of anxiety [29].This is an especially pertinent issue, as they are the subgroup of individuals with ASD's who are mostly likely to drive independently [22,23].
There is a large body of literature suggesting that anxiety has a negative impact on general task performance [30][31][32].The worry and constant monitoring of potentially harmful stimuli reduce the efficiency of working memory, processing speed, and subsequently task performance [33].Several of the cognitive domains impacted by high levels of anxiety are critical to the task of driving, including working memory and information processing [33][34][35].Matthew and colleagues investigated the impact of anxiety on driving, and found more self-reported driving errors and poorer simulated driving performance (e.g., poor steering control) in individuals with high levels of driving anxiety [36,37].As anxiety is a consistently-reported problem in the population of individuals with ASD, it stands to reason that their elevated levels of anxiety may negatively impact their driving performance and confidence [25,38].A recent pilot study investigating the self-reported driving behaviors of licensed drivers with ASD revealed that compared to non-ASD drivers, drivers with ASD report significantly lower ratings of their driving abilities, suggesting that they are less confident in their driving abilities than typically-developing controls; this may be a result of driving anxiety [39].

Processing Speed
Visual processing speed has been defined as "the amount of time needed to make a correct judgment about a visual stimulus" (i.e., detecting a target, identifying a target's spatial location) [40].As this ability is used constantly during the task of driving (e.g., detecting hazards in the environment, judging the spatial positions of other vehicles), visual processing speed is a key skill for navigating the driving environment safely [41].Typically-developing, experienced drivers are able to quickly identify important, safety-relevant aspects of the driving environment (e.g., the cars in front of them, pedestrian crosswalks, traffic lights and road signs) [42].Typically-developing, experienced drivers' increased attention to important areas of the driving environment, and their ability to quickly scan the scene for hazards, provides them with adequate information to drive safely, and allows them to react quickly to avoid these hazardous situations [42].This visual processing speed has been shown in previous research to be underdeveloped in individuals with ASD [43,44].
In the real-world driving environment, the inability to rapidly process a great deal of visual information in an environment and identify important target items (e.g., traffic lights, other cars, pedestrians, stop signs, etc.) could result in an increased risk of motor vehicle collision.These decrements have not only been demonstrated in children with ASD [44]; processing speed impairments have also been shown to persist into adolescence and adulthood, a time period when the task of driving becomes an important part of daily living [21].Adults with ASD have also self-reported difficulties in "processing fast-moving visual events", a description that certainly applies to the complex and dynamic nature of the driving environment [45].Further, the type of hazards drivers with ASD encounter may also affect the speed at which they react to and avoid them [46].

Executive Function
Executive functioning is a broad term that encompasses a myriad of tasks and abilities, and is a commonly-reported impairment among individuals with ASD [47].Although previous research has produced mixed results as to the exact aspects of executive function affected by ASD, generalized impairment in everyday executive functioning is the general consensus throughout the autism research community [43,48,49].Among individuals with ASD, the most commonly-cited impairments in executive functioning occur in the areas of attention, inhibition, and cognitive inflexibility [43,48,49].
Appropriate allocation of attention in the driving environment is essential to driving safety.Sheppard and colleagues [50] investigated this driving skill in non-drivers with ASD, and found that such individuals were slower to orient their attention to driving hazards than those in the typically-developing group.This study is however limited, in that it examined only non-drivers, and used video clips rather than a driving simulator paradigm.Eye tracking results in a study by Reimer and colleagues [51] examining visual attention in a driving simulator also found atypical visual attention in drivers with ASD.Findings revealed that drivers with ASD focused their eye gaze more on low stimulus areas of the driving environment (e.g., looking up towards the horizon where there are fewer cars) than high stimulus areas of the driving environment (e.g., directly at the car in front of them, at pedestrians walking to their right or left) [51].This is particularly dangerous in a real-world driving environment, as higher stimulus areas such as city streets and suburban streets are where hazards often occur for various reasons (e.g., more pedestrian crossings and intersections) [52].
The response inhibition impairments seen in ASD may also have serious implications for driver safety.Driving requires the rapid processing of a great deal of information while simultaneously filtering out irrelevant details and inhibiting responses to those details.If this cannot be accomplished, a driver may miss important information in the driving environment, such as a pedestrian walking into the roadway, while caught up on irrelevant environmental details (e.g., a colorful arrangement of flowers on the sidewalk).Because so much of driving is reacting to the actions of other drivers, cognitive flexibility and response inhibition are essential for safe navigation [53,54].This cognitive inflexibility and difficulty with strict rule adherence have been cited by both teens with ASD and their driving instructors when asked what the most challenging aspects of driving were [12].Teens with ASD self-reported "interacting with other drivers" and "interpreting traffic situations" as some of the most difficult driving skills [12].When these same teens' driving instructors were questioned about the driving situations that were most challenging for their students with ASD, they cited the inflexibility and rule following characteristics of ASD as major barriers to driving.Further, adjusting to unfamiliar situations was one of the most commonly reported problematic skills for drivers with ASD [12].

Driver Performance & Safety Considerations
Objective studies examining the driving safety of individuals with ASD have varied in both the ASD population examined (i.e., non-drivers, pre-drivers and fully licensed drivers) and the findings [55].Reimer and colleagues [51] were among the first to test the driving capabilities of individuals with ASD using a driving simulator.Findings from this brief report suggested that compared to matched, typically-developing controls, individuals with ASD may have elevated heart rates (a possible indicator of stress and anxiety) and unsafe gaze patterns while driving.Sheppard and colleagues [56] also investigated driving safety in the ASD population by examining reaction time to hazardous events.Compared to control participants, drivers with ASD had significantly slower reaction times when identifying hazards with a response button.This is important when considering that delayed reaction time is a significant predictor of motor vehicle collision-related injury or death [57].
Although the innovative driving studies conducted by Reimer [51] and Sheppard [56] examined the vulnerable group of drivers with ASD with a comparison group, they did not examine individuals at varying levels of driving experience, a factor identified by previous literature as having a significant impact on driving performance [58].Cox and colleagues [59] conducted a recent driving simulator study in a population of individuals with ASD who had received their learner's permit (novice drivers).The goal of the study was to examine the role of executive function and basic motor skill in tactical driving performance in 17 individuals with ASD who were not yet fully licensed, but had obtained a driver's permit, compared to 27 typically-developing controls who had just received their full driver's license.Results indicated that the ASD group exhibited poorer driving performance (i.e., increased swerving, increased lane changes); decrements were further compounded with the addition of a working memory task.Findings of the study also suggested that the ASD group had significantly slower hand/arm reaction times (i.e., swerving) when compared to typically-developing controls [59].Not only did the ASD and typically-developing groups have inherent differences in driving experience (i.e., the ASD group had only permits, while the typically-developing group had obtained a full unrestricted license), but they also did not consider inter-group variability in driving experience.
As a follow up to their previous work, Cox and colleagues [60] also investigated the simulated driving performance of novice drivers with ASD and typically-developing, licensed, experienced drivers.As the authors expected, novice drivers with ASD performed significantly worse on all measures of driving performance (i.e., excessively low speed, crashes, off-road driving, missed turns), and had significantly lower overall driving skill scores.Not only were the ASD group's driving skill scores significantly poorer, they were nearly 6 standard deviations below driving skill scores of experienced, typically-developing drivers.However, the significant deficits in simulated driving performance noted in the ASD group may have been due to the vast differences between the ASD and typically-developing groups in terms of driving experience, along with the added impairments associated with ASD.
ASD participants have also reported more intentional violations (e.g., speeding or tailgating), driving mistakes (i.e., making a maneuver without checking mirrors, pressing the wrong pedal), and slips or lapses than did typically-developing controls [39].In another survey, the majority (70%) of parents who had adolescents with ASD who were driving or trying to receive their driver's license reported that their child's autism "moderately" to "extremely" negatively impacted their teen's driving abilities [16].These same parents identified multitasking (e.g., merging while maintaining speed), awareness of traffic, use of mirrors, and maintaining lane position as the most difficult (rated as "very difficult') skills to teach their son or daughter with ASD [16].Turning, speed control, and braking were also rated as "difficult" tasks when teaching their child to drive.
Contrary to the findings of Cox and colleagues [59], a study of the on-road driving behavior of individuals with and without ASD revealed only certain areas of driving deficit (i.e., vehicle maneuvers, left turns) in drivers with ASD [38,61].The performance of drivers with ASD was superior to that of the typically-developing group on driving behaviors related to rule following (i.e., using turn signals, checking for traffic at intersections) [38,61].Strict rule adherence is a common characteristic of individuals with ASD, and may be useful in some driving scenarios (i.e., following the speed limit), but may also prove to be a hinderance in driving situations where rules are unclear, such as driving through yellow lights, encountering collisions, reacting to other drivers' incorrect behavior, and adapting to evolving traffic conditions.Overall however, the majority of studies conducted on ASD and driving suggest that drivers with ASD have significant decrements in driving performance, and may require additional training compared to typically-developing individuals [61].

ADHD
ADHD is a behavioral disorder characterized by inattention and/or hyperactivity-impulsivity [19], and is one of the most common developmental disorders, affecting approximately 8% of the population [62].Within the population of individuals with ADHD, there are three sub-types: ADHD-Predominately Inattentive (presents with 6+ inattentive symptoms), ADHD-Predominately Hyperactive (presents with 6+ hyperactive symptoms), and ADHD-Combined (presents with 6+ of each inattention and hyperactivity) [19].Individuals diagnosed with ADHD-C are at the greatest driving safety risk, as they present clinical levels of both inattention and hyperactivity [6].For individuals aged 17 and older (the large majority of drivers on the road), only five of each symptom category must be present to receive an ADHD diagnosis [19].With this reduction in the symptoms required for an ADHD diagnosis in the latest DSM, there are even more drivers with ADHD on the roadways today.The characteristic impairments in attention and impulsive behavior make the cognitively-demanding task of driving difficult for individuals with ADHD [14,63,64].Teenagers with ADHD have almost four times as many traffic citations and car crashes than their typically-developing peers, and are seven times more likely to have a second crash [63].Further, the relational strain often seen between teens with ADHD and their parents [65] may impact the learning-to-drive period, and reduce the quality of supervised, parental practice for these teens [66].

Inattention
Inattention is one of the hallmark characteristics of individuals with ADHD, and has been attributed by previous research to impairments in executive function [67].Research suggests that impairments in sustained attention seen in ADHD may result in poor academic performance and delayed social development [68].Inattention may not only prove problematic in social and academic settings, but also in the driving environment [69].Visual attention refers to where an individual orients their gaze in a visual field, and is an especially relevant skill in the context of the driving environment [70].Unfortunately, this is a known area of impairment among individuals with ADHD [71].Compared to typically-developing teens, teens with ADHD exhibit significantly more inattention to the roadway in a driving simulator task [72].This inattention to the roadway may not only impact vehicle control, but also the ability to quickly react to hazardous events.
Previous literature on reaction time in ADHD has been fairly consistent in finding greater variability on reaction time in individuals with ADHD as compared to typically-developing individuals [73,74].It has been suggested that the slower reaction times are a result in frequent lapses in attention when responding to stimuli [73,74].Previous studies examining reaction time in the context of a driving environment have shown mixed results, with some indicating slower and more variable reaction times in adolescents with ADHD compared to typically-developing adolescents [75], and others finding no significant differences in reaction time to hazardous events [6,76,77].

Impulsivity
Although impairments in sustained attention pose a significant driving safety risk for divers with ADHD, research also suggests that impulsivity and hyperactive behavior play a role in the driving behavior and elevated motor vehicle collision risk for drivers with ADHD [78].Previous research has also suggested that impulsive behaviors in individuals with ADHD may be related to impairments in executive function-more specifically, inhibition [79].This inability to inhibit inappropriate or unsafe behaviors may result in greater levels of frustration with other drivers (emotional regulation difficulties), and increase risky driving behaviors such as speeding, distracted driving, and driving under the influence [78].A survey of 27 drivers with ADHD found that subjects had driven significantly more kilometers per year, had more traffic authority registrations, more traffic violations, more collisions, and more self-reported insecure and hectic driving styles compared to typically-developing drivers [80].

Medication
Medications are a critical component in the treatment of ADHD, and stimulant medication is often the first line of treatment for teens [81].Previous research suggests that stimulant medications significantly reduce symptoms of ADHD (i.e., inattention, hyperactivity and impulsivity), and can improve adaptive abilities of adolescents with ADHD [82], which includes complex skills such as driving.In a repeated-measures crossover study of teens aged 16 to 18 with ADHD, stimulant medications significantly reduced inattentive driver errors (e.g., swerving into neighboring lanes) but not impulsive/intentional errors (e.g., cutting someone off) [83].This suggests that emotion regulation may also play a role in driving safety for teens with ADHD [63,84].The time frame of beneficial effects, 12-16 h post-ingestion, suggests that the medications must be continued on a daily basis to see sustained improvement in driving abilities.As demonstrated in the studies, stimulant medications have previously demonstrated potentially protective effects for drivers with ADHD in the areas of attention.Current research on ADHD and driving, however, is fairly inconsistent in the inclusion of medication in task performance measures (i.e., take medication before task or abstain for a time frame prior) or accounting for its effects (i.e., medication type and amount are not accounted for).

Driver Performance & Safety Considerations
Predisposition to risky driving behavior and difficulties in attention regulation place individuals with ADHD at a much higher susceptibility to driving distractions than teens without ADHD [8,14].Reimer, Mehler [8] investigated the potentially detrimental effects of talking on a cell phone on simulated driving performance of ADHD drivers between the ages of 17 and 24.Findings suggested that under more challenging driving conditions (e.g., driving in urban areas), young adults with ADHD exhibited a more conservative driving pattern, as indicated by a greater time spent at stop signs and slower driving acceleration; however, this also led to a diminished secondary task performance (in this case talking on a cell phone) compared to controls [8].This study, along with most other studies in the ADHD and driving literature, had a small sample of young adults with ADHD.Participants also performed the driving task without medication.As most individuals with ADHD are taking medication, it is important to consider the impact of medication on these findings.Further, these driving behaviors may not be representative of real-world driving behavior, where the threat of crashing may alter distracted driving behavior.A naturalistic study sought to examine the real world driving behaviors of young adult drivers with ADHD over a three month period using an in-vehicle camera that recorded video and g-force events (e.g., braking or accelerating suddenly).Young adults with ADHD were involved in significantly more MVCs and increased g-force events, more risky and illegal vehicle maneuvers, and distracted driving behaviors, such as removing hands from the wheel to reach for a moving object in the car [85].Although typically-developing controls were matched to young adults with ADHD on age, gender, race, and education, individuals with ADHD were required to have had more than one previous driving violation (collision or citation), which likely biased the ADHD driver group selected.

Driver Training Programs
The growing body of research investigating the driving challenges of individuals with ASD and ADHD have brought to light a variety of potential predictors of poorer driving outcomes.The identification of these factors has led to various interventions to improve driving safety for this vulnerable population of drivers.These interventions include virtual reality, psychological therapeutic techniques, as well as simple modifications to current training programs.

Virtual Reality
With the recent increase in the use and availability of technological solutions, virtual reality has become a safe and ethical means of both testing and training human behavior.Virtual reality is already being used to improve social interactions among children with ASD through the use of social robots [86] and emotional-facial recognition programs [87].Not only has previous research demonstrated the usefulness of virtual reality in reducing anxiety and social impairments, virtual reality driving environments have also shown promise in training and improving driving performance in novice drivers with ASD and ADHD [60,88,89].More specifically, Wade and colleagues have shown improvements in the use of a driving-simulator gaze training system to teach individuals with ASD to look at safety-relevant aspects of the driving environment [90].Although virtual reality interventions have the potential to improve various aspects of driving safety in these vulnerable populations, they are often expensive, and cannot be easily transported to families who need them.

Psychological
As discussed above, impairments in executive functioning play a significant role in the driving challenges associated with both ASD and ADHD.Executive functions can, however, be improved thorough the implementation of cognitive training programs.Cognitive training programs have been successful in reducing crash risk in other vulnerable road users such as older adults [91], which suggests that these interventions may also be useful for drivers with DDs characterized by executive dysfunction [92,93].These improvements in executive function may, in turn, translate to improved driving performance.Individuals with DDs may also benefit greatly from the implementation of proven, therapeutic techniques, such as cognitive behavior therapy (CBT), to specifically target psychological barriers to driving [94].For example, the driving anxiety commonly seen in individuals with ASD may be reduced with the implementation of CBT targeted at reducing fearful thoughts about driving.Computerized hazard identification and avoidance training programs have also been successful in DD populations.Drivers with ADHD demonstrated significant improvements in driving hazard identification response times following a brief computer-based intervention [95].Other promising approaches for teen drivers for ADHD specifically include the Supporting the Effective Entry to the Roadway program [96,97], which involved driver monitoring using on-board diagnostics coupled with symptom tracking and pharmaceutical interventions which are commonly prescribed to teenagers with ADHD [98].

Program Modifications
Modifications tailored to the specific needs of individuals with DDs may also prove to be a useful tool in improving driving safety.Simple changes to the language and vocabulary level in the typical learner's permit study manual resulted in improved success rates among individuals with cognitive limitations (mean IQ of sample = 71) in passing the learner's permit portion of the driver's test [17].This simplified approach to may also be successful in training drivers with DDs to safely obtain not only their learner's permit, but also their full driver's license.Additional practice hours and increased requirements for supervised practice hours may also be beneficial for teens with ADHD and ASD.Another cost effective and useful training program modification that has demonstrated advances for drivers with DDs is commentary training.Rather than the traditional written scenario commonly used in driver's education classes, commentary training allows the driver-in-training to give continuous feedback about what should happen next while watching a taped drive from a driver's perspective [95,99].This allows instructors to put the trainee in dangerous situations to train responses without risking the trainee's safety.

Important Gaps and Unanswered Research Questions
In summary, teen driver safety research with vulnerable populations of adolescents, such as those with ASD and ADHD, is growing.Young drivers with DDs may be an increased risk for driving decrements due to symptoms commonly associated with their particular disorder.For example, young individuals with ASD are less likely to progress to independent driving [23], and the etiology may vary by person-perhaps due to anxiety about driving [12,16], low confidence in driving ability, or poorly developed cognition (e.g., executive function) known to relate to driving safety.These factors may result in greater likelihood of avoidant driving behaviors among individuals with ASD as compared to individuals with ADHD or typically-developing peers.For individuals with ADHD, the underlying mechanisms of driving risks may be different, as these individuals are more likely to engage in distracted driving, and drive at higher speeds [85], but may not avoid complex driving situations that put them at increased risk.
Several notable gaps became more apparent from this literature review.Aside from pharmacological interventions, there is a limited body of literature focused on cognitive and behavioral driver programs for families with a teen diagnosed with a developmental disability, especially those that are individualized to the needs of the teen driver.Such interventions can scaffold medical interventions, providing a stable platform to support lifelong safe transportation.Differences in how the disability is viewed by the family, parental anxiety and values, economic factors, access to health and programmatic resources, and geographic constraints may all influence adolescents' path to safe and independent mobility.Additional research on these factors is essential for providing tailored support to adolescents who want to get licensed and can do so safely.
Little attention has been given to areas of impairment noted in adolescents with ASD and ADHD that are seemingly less related to driving performance, such as social cognition or emotion regulation.Impairments and/or delays in social development and emotion regulation are commonly seen in both individuals with ASD [18,27] and individuals with ADHD [100].Driving is a largely social task that requires interaction with other drivers and anticipation of other drivers' and road users' behavior to negotiate safely [101,102].Very few studies have investigated the impact of these social impairments on driving performance in drivers with ASD [46,56] or ADHD [84].
The populations and methodological approaches used in the current literature on DD's and driving vary greatly, which makes it difficult to draw firm conclusions on these populations as a whole.Studies lack consistency in diagnosis confirmation (e.g., self-report, parent-report, various symptom inventories), appropriate comparison groups (e.g., control groups with equal driving experience and exposure), and driving behavior data (e.g., self-report, driving simulator, observational, parent-report).Additionally, like most psychological research, research on this topic is almost exclusively conducted with "WEIRD" samples-Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies [103].Generalizations to populations of teens with DDs that significantly vary based on cultural, socio-political, and economical factors from those in these studies should be made with extreme caution.Cross-cultural research is essential.
Finally, we are also in an age of rapidly evolving vehicle technologies, including connected vehicles, advanced driver assistance systems (ADAS), and infotainment options.How young drivers with ASD and ADHD are affected by these innovations in vehicle design and capability is largely unknown; the same may be said of adolescents without these diagnoses.It is plausible that ADAS may prove beneficial for drivers who have cognitive limitations that might impede an effective driver response, such as a quick braking maneuver to avoid a potential hazard.On the other hand, behavioral adaptation to varying levels of ADAS could complicate matters, and could reduce the net effect on safety [104] if, for example, the automation results in declines in situation awareness and the driver exhibits delays in taking full control of the vehicle when the ADAS falters or becomes inactive.Preliminary work in this area with typically-developing teens suggests that teens report greater trust in their own skills and competences than in-vehicle technology [105].However, it is uncertain whether teens with DDs would report similar preferences and needs.Autonomous vehicles might provide a unique, safe transportation option, and might also introduce new unforeseen problems.Important overarching questions include the need to understand what capacities and abilities young drivers with DDs must have to safely operate (or ride unsupervised) in these vehicles, what additional accommodations they might need to enhance their safety, and how inequalities in access to these technologies might differentially affect the safety of more marginalized groups of teens.