http://www-fars.nhtsa.dot.gov/
In 2002, US motorists drove 2,856,000,000 miles. There were 42,815 traffic-related fatalities. 87% of these fatalities were drivers or passengers.
Based on these numbers, you will die in a traffic fatality after you travel 150,000,000 miles.
Suppose you drive 20,000 miles a year. That is probably a lot more than the average driver. At that rate you would have to live 7,500 years before you will die in a crash. Factor in the above 87% statistic, and your life span expands to 8,620 years of above average travel before you will die in a traffic crash.