## 4 Exploratory Data Analysis (EDA)
### Analysis of Major Causes  
As observed in Figure 2, the major causes of teen driver crashes in rural West Texas are: unsafe speed (23%), failure to control speed (19%), failure to yield right of way (13%), driver inattention (6%), fatigue or sleep (5%), and animals on roads (6%). Other minor causes are mainly about risky driving behaviors, such as turning or changing lane when unsafe, following too closely, and backibg without safety, etc. It is evident that speeding appeared to be the most important cause of teen driver crashes in West rural Texas regions (nearly 42% of crashes occurred due to high speed of the vehicle (unsafe speed and failure to control speed)). The yearly number and causes of teen driver crashes in West Texas rural areas can be found in Table 1.  
Speeding increases the stopping distance of the vehicles while reducing reaction time to avoid a potential collision. It also increases the likelihood of injury in a crash. There is also evidence from naturalistic driving studies that teens' speeding behavior increases over time, possibly as they gain confidence. In general, they take more risks than adults and are more likely to involve speeding, which becomes more prevalent when driving on rural roads in West Texas at night or with other teen passengers on board. The problem is even worse since Texas has the highest speed limit on its rural highways in the nation (75 mph is a common speed limit setting and 80 or 85 mph will be allowed if the highway is designed to accommodate that speed.) It should also be noted that not all speed-related teen crashes are due to intentional risk-taking. Instead, most are caused by inexperience of teen drivers and a lack of driving skills. Teens or new drivers need to be educated on speed management based on traffic and road conditions and keep a safe distance from other vehicles. The second important cause is mainly related to the improper driving behaviors of teen drivers in West Texas: failure to yield right of way and being distracted while driving (roughly 19% of the total crashes). In some cases, teen drivers of rural West Texas failed to yield to other vehicles while they were merging into the interstate highway, which resulted in crashes. A merging vehicle is usually required to execute a lane-changing maneuver along a limited length of a merge lane, which requires a good control while timing the merging and possesses a high chance of collision [31]. Therefore, teen drivers might not be experienced enough to perform the maneuver properly and get involved in crashes. Additionally, teens' inexperience behind the wheel makes them more susceptible to distraction of electronic devices or passengers in the vehicle. Figure 2: Major contributing factors to teen driver crashes in West Texas rural areas. The third important cause is from the unique hazards on rural roads: fatigue or asleep and animals on the road, which accounts for 11% of the overall crashes. One major concern for teen drivers on rural roads is highway hypnosis. Many rural highways in Texas consist of long, straight roadway sections. This fact, coupled with the propensity for teens to drive late at night, is a likely explanation for high fatal crash counts during night hours in Texas. Highway hypnosis can occur when drivers operate vehicles for extended periods of time in monotonous surroundings, entering a dulled and drowsy state. Low light and lack of sleep can contribute to the issue [2]. Additionally, in West Texas, animal crossings are common in rural terrains. Teen drivers often carelessly endanger themselves by overlooking the unforeseen hazards from animals. Wild animals, such as deer and domestic animals, escape from farms or ranches and dash into oncoming traffic. Inexperienced teen drivers often overcompensate when trying not to collide with the animal and, in fact, cause a collision. Other environmental issues coinciding with rural road animal accidents include lack of lighting and obstructions to visibility.