When considering a question like this, which is a matter of public policy and ethics, it is often a good start to perform a cost-benefit analysis. You may not be able to find relevant data (or, in some cases, it may not exist), but you can still address the question on a theoretical level.
First, think about the costs of raising the driving age. These could be economic or social. Fewer cars and less gasoline would be sold. Young people would find it more difficult to be independent or to travel for work or college. Then look at the benefits. It is important to be clear about these, rather than, for instance, simply asserting that 5,000 lives would be saved. How many of those deaths would have occurred anyway, even with a change in legislation?
On this point, you need to give serious consideration to the difficulties of changing the law. Certain safety laws, such as those requiring seatbelts to be worn and those prohibiting drunk driving, have gained widespread acceptance. However, a law prohibiting some people who can currently drive (and who may already own cars) from doing so is less likely to be obeyed. You should also consider the fact that behavior that is illegal is much more difficult to regulate. This means that it may be more effective to create tougher rules on speed limits or other safety precautions, rather than criminalizing the act of driving for a section of the population that currently enjoys the right to do so.