Initially, we reviewed the title of the first 60 documents resulting from each search. If the document was a manuscript, we then examined its abstract and conclusion. If the content of either the abstract or conclusion was relevant to the subjects of interest , the manuscript was selected for further review of the entire manuscript. For the cases in which the document was not a manuscript , we skimmed through the document to assess its content. Content relevance to the topics of interest was evaluated manually and individually by two researchers to establish inter-rater reliability.30 When both researchers agreed on a certain content, the document was further reviewed. The third step of the review process was performed by searching for specific keywords within each document selected in step 2. For example, for each source found in the search for the required physical and mental capabilities of youth, keywords such as force, anthropometry, body size, weight, and strength were searched to identify the relevant material. In the last step , experts in youth and ATV safety reviewed and categorized the relevant information in each document in a table. Based on our search terms, we retrieved 182 documents from Google Scholar and 1,189 from Google. As expected, some documents were repeated due to the five separate queries in two search engines. After filtering the titles, we identified 649 unique documents. Among those, 115 documents were selected for further review based on the inclusion/exclusion criteria. Our findings are outlined in the next section of this manuscript.A summary of the literature review process is illustrated in Figure 1. In addition to the initial literature review , hemp drying racks we also evaluated documents that were directly cited by the original 115 selected documents that emerged from our search. For those documents, we repeated steps two , three , and four .
After filtering the titles, we identified four additional documents.ATVs can weigh up to nearly 1,200 pounds31 and reach speeds up to 80 mph.32 The engine size ranges from 50 cc to approximately 1,000 cc for youth and adult-size ATVs. Controlling heavy, fast, and powerful vehicles require physical and mental capabilities that youth operators may not possess. For this matter, several consensus-derived guidelines, rules, and recommendations have been developed regarding the minimum age for operating ATVs on farms. These guidelines include age limitations for youth to ride utility ATVs and youth models. Nevertheless, these recommendations are inconsistent and may be affected by laws that vary among states. The American National Standard Institute/ Specialty Vehicle Institute of America propose age limitation based on the abilities of children from different age groups and the ATV’s maximum speed. Furthermore, based on the medical associations and safety experts’ concerns about child safety and health, some have concluded that permitting children younger than 16 years-of-age to operate or ride ATVs could be construed as a form of child neglect or endangerment. According to ANSI/SVIA, youth under the age of 6 should not be allowed to operate ATVs, and youth aged 6–10 should be limited to motorized vehicles that can go no faster than 24 km/h and require constant adult supervision. Youth between the ages of 11 and 12 can ride ATVs with a maximum speed of 48 km/h . In the U.S., ATV manufacturing and sales are regulated by the U.S. Consumer Product Safety Commission and not by the U.S. Department of Transportation . The DOT regulates motor vehicles designed to be used on public roads, and ATVs are not intended for public roadway use. In 2002, nine consumer groups petitioned the CPSC to ban the sales of adult-size ATVs for use by children under the age of 16.
However, the petition was denied. The CPSC, theindustry, and many consumer advocates recommend selling only youth-model ATVs for children. Nevertheless, there are no ATVs designed/manufactured for children younger than 6. Vehicles for children 6 years-of-age and older have traditionally had engine sizes less than 70 cc, and those for children 12 years-of-age and older have been 90 cc or less. The CPSC recommends that these vehicles be used by children with adult supervision. Previous recommendations based on engine size by operator’s age are given in Table 2. In the case of ATVs, the CPSC currently has adopted the 2017 voluntary standard developed by the Specialty Vehicle Institute of America and the American National Standards Institute , which is the most up-to-date standard regarding ATV-youth fit. The American National Standard for Four Wheel All-Terrain Vehicles42 is a “voluntary” standard that provides definitions for youth category ATVs . Based on this standard, the criterion determining age-designated youth labels is the maximum speed of the vehicle. For example, Y-10+ ATV models should only be used by children aged 10 and older. The maximum speed associated with each ATV category is presented in Table 3. The European standard titled “ATV Safety requirements and test methods” determined several requirements that ATVs should meet to be commercialized in Europe. This standard categorized youth-ATVs into four groups, including, Y-6+, Y-10+, Y-12+, Y-14+ based on the speed limits, similar to the standard from ANSI/SVIA . In addition, the European standard suggests that only operators older than 16 should ride adult-sized ATVs for utility or recreational purposes. Despite the recommendations based on age categories, several national and international organizations prohibit youth under 16 from riding ATVs of any size . Moreover, several medical associations inthe U.S., including the AAP40 and the ACS,41 warn that all ATVs are unsafe for youth, and no one under 16 years should ride ATVs at all.
Some also indicate that youth under 12 have neither the required physical capabilities nor the motor skills to safely handle an ATV. They also indicate that youth under 16 do not possess the cognitive capabilities required to control highpower motorized vehicles. Lastly, Franklin et al. advocated that the sales of youth-size ATVs should be stopped in Australia for safety reasons. There are different regulations and laws at the state and federal levels. However, most rules/laws do not pertain to operations on private land. In addition, most laws are exempted if the vehicle is used for agricultural purposes. For instance, operators can ride without a helmet if they are farming in North Carolina or Wisconsin. In addition, ATVs in Pennsylvania used exclusively for agricultural purposes are classified in the Pennsylvania Vehicle Code as multipurpose agricultural vehicles and are exempt from the Pennsylvania ATV law. None of the states’ regulations address the physical or mental capabilities required to ride the ATVs. Numerous studies related to youth’s age and ATV use have been conducted; two key studies regarding the age of youth’s involvement in agricultural activities and age-based patterns in youth ATV riding behaviors are summarized in .The ATV operator should be strong enough to activate the ATV controls, including the throttlelever, hand gearshift lever, foot gearshift pedal, ignition switch, headlight switch, handlebar, hand brake lever, and foot brake pedal. An operator’s inability to consistently activate these critical ATV components could increase the injury risk to operators and bystanders. Several reviewed documents discussed the required strength to activate different ATV controls. However, most of these documents relied on qualitative criteria for evaluating the required youth strength. For instance, the National Children’s Center for Rural and Agricultural Health and Safety ATV guidelines state that “youth should be strong enough to operate the controls without straining and be able to push the ATV off if pinned underneath.” Furthermore, the ATV Safety Institute ’s “readiness checklist” recommends that “youth should have enough strength to activate the hand controls, shift lever, parking brake, choke and fuel valve, and the brake lever with sufficient pressure.” In contrast, industrial rolling racks the British Standard Institution , provides quantitative data for actuation forces of some ATV controls. For example, BSI recommends hand lever brake activation forces between 22 N and 245 N for all adult-sized ATVs. In an ongoing study, Araujo and Khorsandi measured the forces required to activate the main ATV controls. The activation forces were then compared to the corresponding strength of youth of various strength percentiles , genders , and ages . The authors found a significant mismatch between the forces required to operate the ATV controls and the corresponding strength of most youth. Furthermore, several study articles and guidelines reviewed in this manuscript recommended that youth should be capable of performing active riding, which refers to the operator moving their pelvis on or off the seat to counterbalance forces while holding the handlebars and keeping both feet on the footrests.
Some researchers reported that active riding increased the stability of the ATV and decreased the chance of a rollover. However, the capability of performing effective active riding requires that the youth weight be significant compared to the ATV weight. Based on the CPSC, the appropriate child to ATV weight ratio should be 1:3.44 Figure 2 shows the weight of the lightest and heaviest youth in each age group compared to the mean weight of an age appropriate ATV. Based on the youthATV weight ratio recommended by the CPSC, 95th percentile kids as young as 7 years old are too heavy for the ATV recommended for their age , and by age 14, most kids are too heavy for ATVs designed for 12–15-year-olds. Based on the CPSC youth-ATV ratio recommendations , adolescent youth aged 12 to 15 years old might be too tall or heavy for the youth-model ATVs currently on the market and approved by the CPSC. If a youth is too tall or overweight, their knees may interfere with the handlebars, and they will be unable to control the ATV properly. Moreover, overly tall or heavy youth may significantly raise the center of gravity when on youth-size ATVs, affecting their stability and riding. A higher center of gravity likely increases the probability of the vehicle rolling over, posing a risk of injury or fatality. Different standards and organizations have developed recommendations to evaluate youth’s ability to effectively reach the ATV’s main controls: handlebar, hand brake, foot brake, hand gearshift, foot gearshift, and throttle lever. A summary of youth-fit criteria for ATVs proposed by various organizations and a research manuscript are shown in Table 5. In addition to reaching different controls, the European standard and the N4-HC55 suggest evaluating hand reach to hazardous zones on the ATV . This recommendation is based on another standard , which determines safety distances required to prevent hazard zones that could burn operators from being touched by upper and lower limbs. A previous study evaluated the fit of one adultsized ATV and one youth-model ATV for male youth aged 6–15 years old based on 5 of the safety recommendations mentioned in Table 5. The study found that most youth aged 6–15 years did not anthropometrically fit the ATVs based on the fit criteria used. Furthermore, the study suggests that rider age and ATV engine size are poor indicators of youth-ATV fit, and quantitative metrics would improve the assessment of which rider can anthropometrically fit which ATV. Furthermore, Araujo et al. evaluated youths’ ability to reach the main controls of various ATVs following some of the safety recommendations presented in Table 5. The authors developed virtual 3D mockups of ATVs and youth and simulated their interaction using an ergonometric software. The study’s major finding was that most youth failed to pass at least one of the ATV-youth fit recommendations.The field of vision of an ATV operator is the visible area they can scan from their seated position on the vehicle. Many believe that youth operators have a reduced field of vision compared to adults. Youth’s limited stature and eye height while seated on an ATV may affect their field of vision. Previous studies have shown that a restriction in an operator’s field of vision significantly increases the likelihood of a crash and/or loss of control which can lead to rider and bystander injuries. The ATV operator should have a wide field of vision to better access ATV controls, keep the ATV on the path, and detect shapes, sizes, and distances of obstacles. This ensures that the operator can react to unexpected riding situations and make decisions about riding strategies. The ASI youth “readiness checklist” includes a section to help parents assess their children’s visual perception. This part of the checklist evaluates youth’s capability to see, perceive depth, have adequate peripheral vision, judge the speed of moving objects, estimate the distances of objects , and follow the movement of objects.