Which logical fallacy is used in the text?
That teenager just ran a stop sign! That settles it: teenagers are bad drivers.

 - appeal to nature: the assumption that natural things are always good
 - ad hominem: an attack against the person making the argument, rather than the argument itself
 - hasty generalization: a broad claim based on too few observations
The text argues that a single teenager running a stop sign indicates that all young people are bad drivers. However, a single observation is usually not enough to draw a conclusion about a much bigger group of people. This illustrates a type of logical fallacy known as a hasty generalization.