Preventing incidents is an imperative task for governments. Implementing safety of peatons and everyone on the road is a very fundamental task for a country and for its reputation.
Many observers and journalists had pointed out that if the legal age for driving was higher, there was a higher probability of safety on the roads, while the debat about that issue is still opened and miscellaneous.
For experts and scientists, safetys level is not based on ones age but on ones responsability, That means that while a youngster can be very responsible, someone driving since decads can be very dangerous, in particular those who was fined in past for drunk driving, in particular in those country where drinking limited amount of alcohol is tolerated by the law. Experts believe this could be dangerous.
I would say that while it is rather difficult for normal people like us to determine which policy make us safer when we drive or walk in public streets, emotional answers (like those who affirms that safety is affected by the age) could make the understanding of the phenomenon vicious. Experts are so called because they should be competent in their areas, so I strongly believe we should listen them, instead of giving our opinions basing on non scientifical facts.