California highways are dangerous, and there is no need to make them any more so by unsafe driving practices. Hopefully, your child's drivers' education curriculum has underlined this idea, but there is always room for reinforcement of such an important idea.
Whether you are reacting to a recent encounter with a law enforcement professional or you are attempting to prevent such issues, there are a few things you might be able to do to get through to your teen about safer driving. One thing you might want to keep in mind: in general, kids see driving as an adult privilege. Therefore, treating them like adults when discussing driving fits better with their perspective — and is more likely to get the results you want.
Of course, with adult privileges come more responsibility. As a parent, you cannot legally shift certain responsibilities onto your children — you could still be liable for injuries that occur due to their actions. However, you could motivate them to drive safely by explaining the consequences of their actions. For example, make it clear that you would expect them to handle court fees or ticket costs. If their own resources were at stake, they could be more likely to avoid the dangerous driving that leads to penalties.
You could also attempt to supplement their education. Specifically, driver's education classes are infamous for glazing over the topics of supposedly minor license penalties in favor of discussing drunk driving, massive injuries or other dramatic situations. The State of California DMV has a useful teen section that discusses everything from getting a license to the finer points of ticket penalties.
At this point, you probably take your driving skill and experience for granted — but these things are likely new and exciting for your teen. You could potentially prevent various problems, including traffic offenses and the resulting DMV issues, by continuously communicating your expectations to your child. This is not intended as legal advice, but rather to educate you about the subject.