Abstract
BACKGROUND:
All Terrain Vehicles on public roadways become major risk factors for the motorists.
OBJECTIVE:
To compare characteristics of crashes and injury severity related to single vehicle (SV) and multi-vehicle (MV) All-Terrain Vehicle (ATV) roadway crashes in Pennsylvania, USA.
METHODS:
Data on ATV crashes occurring on public roads during the years 2010–2013 was obtained from the Pennsylvania Department of Transportation (PennDOT) and analyzed.
RESULTS:
Almost two-thirds of the incidents were single-vehicle incidents. Single-ATV incidents have a greater risk for incapacitating injury to drivers than do multi-vehicle ATV incidents. Other factors that increase risk for incapacitating injury in SV crashes include being male, being a driver, alcohol/drug involvement, hitting a fixed object, and the incidents in non-daylight hours. For MV ATV incidents, head on and rear-end crashes and drivers who had alcohol/drug involvement were the two major incapacitating injury risk factors.
CONCLUSIONS:
This study has enabled us to better understand roadway ATV incidents, characteristics of SV and MV ATV crashes, and the incapacitating injury risks in both SV and MV crash incidents. Our study suggests that road safety and public health programs should focus on the users’ knowledge on laws regarding ATV usage on public roadways.
Introduction
All-terrain Vehicles (ATV) are off-road, motorized vehicles having 3 or 4 low-pressure tires, a straddle seat for the operator, and handlebars for steering control [1]. In the USA, there are more than 10 million ATVs in use [2]. Between 1982 and 2014, ATV incidents have accounted for 13,617 deaths in the United States. An estimated 23% of these (n = 3,098) involved children younger than 16 years of age [3]. Pennsylvania had the third highest number of reported ATV-related deaths (n = 604) for the years 1982 through 2011 in the United States (approximately 20 fatalities every year) even with the regulations concerning helmet-use and restricting the operation of ATVs by youth[3, 4].
ATVs are not intended for on-road use and have design features that can increase risk when operated on paved surfaces [1]. However, the majority of ATV rider deaths occur on roads [5].
Past studies of ATV crashes have focused on the following factors: (1) crash characteristics; (2) driver characteristics; (3) vehicle characteristics; and (4) location. Contributing causes in ATV crashes include carrying or being a passenger, driver error, poor judgment, and loss of control. The most common types of mechanisms of injury in ATV crashes have been reported as rollovers, falling off a vehicle, and colliding with an obstacle [6].
Driver characteristics of ATV crashes include driver demographic factors such as age and gender. It was reported that 80% of the drivers involved in roadway incident were male and 70% of the drivers were older than 16 [7]. In another study, it was reported that 90% of the fatally injured drivers were male and age 16 and older [5].
Previous studies have reported low helmet usage and alcohol involvement in ATV crashes [5, 8]. One study compared roadway ATV fatalities with off-road ATV fatalities and found that roadway crash victims were 44% less likely to be helmeted than off-road victims, and 77% more likely to be in crashes involving alcohol [7]. Studies also showed that ATVs were involved in more on-road than off-road fatal crashes [5, 9].
Most of the roadway incidents involving ATVs are single vehicle incidents and it has been documented that single-vehicle (SV) and multi-vehicle (MV) incidents have different mechanisms of occurrence, critical risk factors, and accordingly, different injury mitigation strategies [5, 10]. Therefore, it is important to investigate the SV and MV ATV incidents separately in terms of crash and driver characteristics, crash causation, and injury severity to develop the most effective ATV crash prevention strategies. The objective of this study was to compare the characteristics of crashes and injury severity related to the single- and multi-vehicle ATV roadway crashes in Pennsylvania (PA), USA.
Methods
The Pennsylvania Department of Transportation (PennDOT) has detailed traffic crash data tables that describe the crash, vehicles, person, roadway, and environmental characteristics. The 4 years (2010–2013) of crash data was requested from the Pennsylvania Department of Transportation in 2014. All personally identifiable data were removed by PennDOT before sending the database to the researchers. All database tables in related years were merged by using the key variables (Crash Record Number-CRN and unit number) in Microsoft Access. The file was then exported to the Statistical Package for the Social Sciences (SPSS) for Windows and analyzed [11]. Based on the variables of “vehicle type”, only crash records involving at least 1 ATV were selected for this study. The number of ATVs involved in a crash was used to assign a case as a SV or MVincident.
Based on the PennDOT data, injury severity was identified as not injured, killed, major injury, moderate injury, minor injury, injury-unknown, or unknown. In this study, we calculated the odds of having incapacitating severe injuries as those incidents that included fatal and major injury. Logistic regression analysis was used to calculate odds ratios and 95% confidence intervals (95% CI). Odds Ratio (OR) is defined as the probability of an incapacitating injury divided by the probability of a non-incapacitating injury [12]. A higher odds value indicates a greater likelihood of a more incapacitating injury.
PennDOT crash data descriptors are grouped into various categories for calculating the risk factors for having an incapacitating injury. The categories and descriptors are listed below. These categories and descriptors are the variables used to analyze the data and appear in Tables 3 and 5.
Environmental/roadway conditions: lighting condition (non-daylight vs. daylight), road conditions (non-dry vs. dry road), weather (bad vs. good weather, with ‘good’ defined as no adverse conditions), road location (rural vs. urban), road type (non-intersection vs. intersection).
Vehicle/crash variables: vehicle movement (ATV going straight vs. non-straight), collision type (non-collision vs. others, hit fixed object vs. others, rear end/head on vs. others, angle sideswipe vs. others)
Person variables: person type (driver vs. passenger), driver’s gender (male vs. female), driver’s age (19 and under vs. others), alcohol/drug use by drivers (alcohol/drug used vs. not used), presence of passenger (with passengers vs. no passenger), seating position of passenger (passenger in front seat vs. other seats).
Variables describing contributing driver actions: distracted driver, driver inexperienced, affected by physical condition, driving too fast for conditions/speeding, driving on the wrong side of roadway, making improper or careless turn, making improper entrance/exit to/from highway, over or under compensation at curve.
Because of the different sample size, in some analysis we could not conduct the analysis for SV or MV. For example for MV crashes, we could not analyze the gender differences because of the small sample size. Similarly, hitting fixed object only observed for SV incidents while rear end/head on crashes and angle/sideswipe crashes were two collision types seen in MV incidents.
Results
Crash and occupant characteristics
There were 983 ATV-involved incidents occurring in PA during the 4-year period, of which 61% (n = 608) was single-vehicle (SV) and 38% was multi-vehicle (MV) (Table 1). In SV incidents, the leading collision type was hitting a fixed object followed by non-collision events, which were mostly ATV rollovers. The data for MV incidents show that angle collisions were the most common collision type (Table 1).
Crash characteristics for SV and MV incidents
Crash characteristics for SV and MV incidents
A total of 767 vehicles were involved in the 375 MV incidents. These 767 vehicles consisted of ATVs (n = 413), automobiles (n = 157), SUVs (n = 67), small trucks (n = 61), vans (n = 23), motorcycles (n = 18), large trucks (n = 12), and others (n = 16), such as bus, snowmobile, farm equipment, horse and buggy, (data not shown). In 38 MV crashes, more than 1 ATV was involved in the incident: 2 were involved in 33 incidents; 3 were involved in 3 incidents; and 2 ATVs and 1 other vehicle was involved in 2 incidents (data not shown).
Prime factors are descriptive conditions or situations identified by the investigating state police officer(s) that best communicates why the incident occurred (Commonwealth of PA-Crash Report Manual, 2016). Prime factors are chosen from conditions/situations listed under the 4 categories of a) driver actions; b) environmental/roadway factors; c) vehicle failures: and d) pedestrian actions (Table 1). For nearly all ATV incidents, the prime factor was driver actions (94% for SV; 98% for MV). A small percentage were due to environmental/roadway factors, vehicle, and pedestrian (Table 1). The contributing driver actions will be explained in later sections. There were 29 Environmental/Roadway prime factors (24 for SV; 5 for MV), 2 Pedestrian (1 for SV; 1 for MV), and 17 Vehicle incidents (14 for SV; 3 for MV).
There were a total of 1,810 occupants (i.e., drivers and passengers) involved in ATV related roadway crashes. Of these, 1,293 (71%) were either ATV drivers (n = 1,010) or ATV passengers (n = 302). Nearly 74% of the passengers were involved in SV ATV incidents. The analyses below are limited to ATV drivers and passengers (Table 2). Overall, persons involved in SV incidents were older than those in MV incidents, based chi-square analysis (Pearson Chi-square = 43.686, P < 0.0001). Almost 63% and 68% of the SV and MV passengers were 19 and under, respectively. Fewer male drivers were involved in SV incidents than in MV incidents (82% vs 92%; Pearson Chi-square = 25.833, df = p<0.0001). A total of 80 people were killed in ATVs over the 4 years. More SV drivers (32%) were killed or had a major injury than MV drivers (19%) (Pearson Chi-square = 23.232, P < 0.0001). SV incidents had a significantly higher percentage of incapacitating/fatal injury than did MV incidents for both drivers and passengers (29.0% vs 17.6%, Pearson Chi-square = 21.582, P < 0.0001). More than one-third of the SV drivers had alcohol/drug involvement (32.6%) which was significantly higher than drivers involved in MV incidents (12.5%) (Pearson Chi-square = 59.215; P < 0.0001).
Occupant characteristics for SV and MV incidents
*Unknown/missing data were not included in the column percentages.
In regard to helmet usage, helmet usage was low (22%) among ATV drivers with no significant difference between SV and MV drivers (Pearson Chi-square = 3.599, p = 0.058). Regardless of a SV or MV incident, helmet use varied with drivers’ age (Pearson Chi-square = 80.127, p < 0.0001): 50% of those under 13 years of age, 43% of the 13–15 year olds, and 27% of the 16–19 year olds were reported wearing a helmet at the time of the incident. Helmet usage was 14% for those 20 years old and older? (age groups vs. helmet usage data not shown in Table 4).
Risk factors for Injury Severity for SV and MV Incidents
*Statistically significant (P < 0.0001).
Frequency of contributing driver actions by ATV drivers
At the time of the incident, 244 ATV drivers (24% of all ATV drivers) were carrying 302 passengers. The percentage of ATV drivers who were involved in an incident while carrying 1 or more passengers was 28% (169 of 608) and 19% (75 of 402) for SV and MV incidents, respectively. Of these, the number of the ATV drivers who were carrying more than 1 passenger was very small (4% for SV incidents, 1% for MV incidents) (data not shown). Out of 182 ATV drivers under 16 years of age (Table 2), 95% (n = 172) of them were riding without adult supervision (126 of them driving alone, 46 of them riding with passengers under 16).
Odds Ratios (ORs) for incapacitating (fatal and major injury) incident involvement in ATV incidents are given in Table 3. In general, SV incidents in non-daylight conditions (OR = 1.4) were significantly associated with more severe crashes. For SV incidents, hitting a fixed object and for MV incidents, rear end and head on collisions increased the risk of having incapacitating injury almost 1.5 times for SV incidents and 2.5 times for MV incidents compared to other collision types. Angular (angle/sideswipe) crashes for MV incidents were less likely to result in severe injuries than other collisiontypes.
SV incidents were found to be 2 times (OR = 1.9) more incapacitating than MV incidents for all persons. ATV drivers had a higher risk of incapacitating injury than passengers. Driver injury severity was significantly associated with age, gender, and alcohol usage. Male drivers had higher incapacitating injury risk than female drivers for SV incidents (analysis not conducted for MV incidents). Younger age was associated with a decreased risk of incapacitating injury for SV drivers (19 and under vs. older drivers, OR = 0.6 for SV and MV drivers). Our analysis indicates a very high risk of incapacitating injury for drivers with alcohol/drug involvement: the risk was OR = 1.9 and OR = 4.9 times more than for drivers with no alcohol/drug involvement for SV and MV drivers, simultaneously. Helmet usage was not significantly related to the risk of having incapacitating injury.
Out of 244 ATV incidents where the driver was carrying a passenger, there were 98 that resulted in an incapacitating injury (killed or major injury). This included 45 drivers and 53 passengers (data not shown). However, ATV drivers carrying passengers had a lower incapacitating injury risk than those without a passenger (OR = 0.5 for SV and MV).
Contributing driver actions and injury severity
In the PennDOT database, there were up to 4 contributing driver actions assigned to each crash incident for each driver. We identified a total of 1,405 contributing actions by ATV drivers: 65% had one contributing driver action, 22% had two actions, 13% had three and more contributing driver actions. In PennDOT database, 30 different driver contributing factors were listed. In Table 4, we specified 8 most frequent contributing driver actions plus the “Others” category. Driving too fast for conditions/speeding (27%) was the most common contributing driver action followed by inexperienced drivers (10%) and drivers who were affected by a physical condition (10%) (Table 4). ‘Other’ category, includes other improper driving actions (n = 260), running stop sign (n = 36), failure to maintain proper speed (n = 29), driver fleeing police chase (n = 23), running red light (n = 22), sudden slowing or stopping (n = 21), proceeding without clearance after stop (n = 19), careless passing or lane change (n = 17), tailgating (n = 17, and others (n = 41) (data not shown in Table 4).
Table 5 shows the odds of having an incapacitating injury by driver actions. Drivers who were affected by a physical condition had the highest likelihood of an incapacitating injury for MV drivers (OR = 3.9) Affected physical condition may include sleepiness, fatigue, sickness, eyesight, hearing problems, alcohol and drugs, and medication.
Injury severity by contributing driver actions
Injury severity by contributing driver actions
*Statistically significant (P < 0.0001).
Statistically significant factors for SV drivers were who over or under compensate at a curve in the road (OR = 1.9) and affected by a physical condition (OR = 1.5). Inexperienced drivers had significantly lower incapacitating injury than experienced drivers for SV drivers. Other contributing driver actions did not significantly differ in terms of injury severity.
This paper reports on the results of comparing SV and MV roadway ATV incidents. The detailed findings on risk factors in SV and MV crashes will add to the existing knowledge of injury studies about ATV roadway crashes.
The first major risk factor appears to be riding ATVs on public roadways even though ATVs are illegal to operate on state or local roadways [13]. PA State law prohibits operating ATVs on any street or highway except when crossing a road, bridge or culvert. Despite the laws, there were 983 roadway crashes in PA in 4 years resulting in the death of 80 people in ATV crashes. The PA State law exempts emergency conditions and roads designated as ATV roads. Also no one under 16 may cross a highway or operate an ATV on designated roads unless in possession of a safety certificate and with an adult 18 or older. In this study, 95% of the youth under 16 was either riding with young passengers or riding alone. There was no information about the possession of a safety certificate in the PennDOTdatabase.
We found that the presence of passengers was more likely in SV crashes (222 passengers; 74% of all passengers) than MV crashes (80 passengers; 26% of all passengers). In previous studies, passengers have been shown to be an independent risk factor for injuries since they can contribute to distraction and loss of control because the additional mass (weight of passengers) can change the center of gravity [9, 14]. In our study, 24% of the ATV drivers were carrying passengers at the time of the roadway incident.
In our study the presence of a passenger or passengers in both SV and MV crashes was found to be associated with lowered incapacitating injury risk. The lower incapacitating injury risk when carrying a passenger may be explained by more cautious behavior by the driver when they have a passenger. The protective effect of carrying a passenger was also confirmed by previous researchers [15, 16].
Gender was identified as a significant incapacitating injury risk factor for SV ATV incidents; male drivers had a higher risk for incapacitating injury in ATV roadway crashes than female drivers. This was a common result found by earlier studies [17, 18].
SV drivers had significantly higher alcohol/drug involvement than MV drivers (32.6% and 12.5%, respectively). Consistent with previous research, for both SV and MV incidents, alcohol/drug involved drivers had more incapacitating injuries when compared to other drivers where alcohol/drug usage was not indicated. The use of alcohol/drug had a clear effect on having incapacitating injury (OR = 1.9 for SV: OR = 4.9 for MV drivers). The higher incapacitating injury risk for MV drivers with alcohol/drug involvement may be a result of the combination of alcohol/drugs and the other vehicle inflicting more injury on the drivers of the ATV.
This study analyzed contributing driver actions by ATV drivers and found, as have others, that driving too fast for conditions/speeding was the most common contributing driver action [5]. However, driving too fast for conditions and speeding was not significantly associated with an increased risk for an incapacitating injury. We also studied incapacitating injury risk by contributing driver actions and found that drivers who over- or under compensated at curves and drivers who were affected by a physical condition were significantly more likely to have a incapacitating injury. MV drivers who were affected by a physical condition had almost 4 times the likelihood of having an incapacitating injury than did the drivers who were not affected by a physical condition.
Limitations
The data used in this study reflects information from a single U.S. state and a single data source (PennDOT). A general limitation of using the PennDOT crash database is that these data are based on police reports and may be affected by the discretion of the traffic officer, which could affect the consistency of crash reports. It is also possible a small number of crashes of potential interest were not investigated by the police due to a lack of police availability, or because the crash parties agreed to not report incidents involving no or minor injury or property damage. Another limitation of the database was inadequate information about the roadway surfaces, preventing any analyses of the effects of roadway surfaces on the crashes. A final limitation of the database is the inability to discriminate between recreational and occupational ATV usage. The collection of such data may enable better targeted driver education programs. In terms of injury severity, the number of fatalities may not be reported accurately since any injury which causes death after 30 days of a crash is not reported. There is no follow-up information reported in the database for deaths occurring after 30 days.
Conclusions
Despite current law, ATVs are used on public roadways and a significant number of roadway ATV incidents occurred in PA over the 4-year study period. These incidents resulted in at least 80 fatalities to drivers and passengers. Most ATVs are not designed to carry passengers. If this safety rule were strictly adhered to, at least 53 passengers could have avoided being killed or seriously injured.
This study has enabled us to better understand roadway ATV incidents, characteristics of SV and MV ATV crashes, and the incapacitating injury risks in both SV and MV crash incidents. Almost 38% of the crashes involved other vehicles and this fact shows that the presence of the ATVs on public roadways particularly put the other vehicle occupants in danger as well as ATV occupants. In terms of injury severity, this work suggests that alcohol/drug usage plays a major role in both SV and MV incidents.
Our study suggests that current ATV roadway safety laws and warnings against ATV riding on paved surfaces may not be well understood or complied with by ATV operators. One solution for a significant reduction of multi vehicle ATV related incidents is to separate ATV pathways. Considering the educational efforts, our study suggests that primary educational efforts should be focused on the ATV users’ knowledge/beliefs on ATV’s roadway usage. Efforts to make the ATVs safer such as installing roll bar, crash prevention devices can provide protection against severe injury and fatality but the best way for both ATV users and other vehicles to stay safe is not to use it on roadways.
Conflict of interest
The authors have no conflicts of interest and were solely responsible for study design, data analysis, and manuscript preparation and editing.
Funding sources
No outside funding.