Learning to drive is important to the independence of teenagers, but it is also a great responsibility．Although having a law that keeps 16-year-old drivers from having more than one teenager in the car with them at first seems unfair, there are convincing reasons for this requirement．
The Insurance Institute for Highway Safety reports that teens are four times more likely than older drivers to be involved in an automobile accident．It also reports that 16-and 17-year-old drivers are twice as likely to have an accident if they have two teenage friends in the car and four times as likely to have one if they have three or more teenage friends in the car with them．Fatal （ 致命的） crashes of 16-year-old drivers involve the highest percentage of speeding, driver error, and number of passengers．This information is enough to cause any reasonable person to wonder about the wisdom of allowing new teen drivers to take a carload of friends anywhere, even if the law permits it．
A study at the National Institutes of Health indicates that the part of the human brain that controls judgment and evaluates the consequences of our actions might not be fully formed until the age of 25．Until this study, researchers had placed the age at 18．If this is true, it could explain the reckless （鲁莽的） behavior of many teens, behavior that often extends into their twenties．It also could be a strong reason for being cautious about the driving circumstances of young people．
This is not the only study that indicates such caution is necessary．One study at Temple University in Philadelphia examines the results of peer（同龄人） pressure in risky driving situations．The study, which uses a driving game, has an individual guide a car through a course, both alone and in the presence of friends．Three different age groups participated in the study: 13-16, 18-22, and 24 and older．Members of the oldest group showed caution whether driving alone or with friends present, but the two younger groups took more chances when they were with their friends．Furthermore, because these drivers were accustomed to the noise and distraction of many passengers, they were unable to see their own mistakes．Once again, this is a good indication that a law restricting the number of teenagers in the car with a young driver is a good idea．
What does the author mainly tell us in Paragraph 2?

A．Many deaths have occurred because of inexperience and overconfidence．

B．It' s reasonable to severely limit the passenger number of teen drivers．

C．New teen drivers have to ask permission before driving with friends．

D．There are many causes behind the teens' driving accidents．

From the two studies, the author probably suggests that ______．

A．different age groups have different peer pressure

B．teenagers often give wrong judgments above passengers' noise

C．underdeveloped brain makes teens ignore their mistakes

D．driving circumstances are bound up with（与…密切相关） the risk of accidents

We can infer that the law restriction can probably ______．

A．protect teens on the highway

B．raise teens' sense of responsibility

C．reduce the number of fatal crashes

D．force teens to drive with caution

With which statement would the author most likely disagree?

A．Some teenagers have risky behavior while driving．

B．Certain laws treat teenagers and adults differently．

C．We still need more studies on teen driving．

D．Driving is important to a teenager' s sense of independence．