Less than you might think. Studies have consistently shown that experience matters much more than age. Though holding experience constant 17 year olds are more

Less than you might think. Studies have consistently shown that experience matters much more than age. Though holding experience constant 17 year olds are more likely to get in accidents than 22 year olds, an 18 year old with two years of driving experience is much less likely to get into an accident than a 25 year old with 1 year of driving experience. Furthermore, accident rates start increasing with age at only the mid 20's, perhaps due to decreasing reaction time with age.