The 99 days from Memorial Day to Labor Day are deadliest time for teen drivers, and July 4th tops the list.

Knox County ranks 7th in the state for teen crashes according to crash data from AAA. The county had 5,855 crashes involving drivers age 15 to 20 in 2013; that's almost 140 crashes per 1,000 teen drivers. That number is up from the last two years, but down from almost 6,000 in 2010.

Number 1 in the state is Chattanooga's Hamilton County with a crash rate of more than 162 crashes per 1,000 teen drivers.