Road rules: 1 in 6 drivers would flunk
A new study says about 33 million American motorists would not be able to get a license if they had to take a written test.
NEW YORK (CNNMoney.com) -- About one in six U.S. drivers wouldn't be able to pass a written driving test if they took it today, according to a new study.
The 2008 GMAC Insurance National Drivers Test found that 16.4%, of drivers, or 33 million, don't know the rules of the road.
The survey presented 5,524 drivers from all 50 states with 20 questions derived from official Department of Motor Vehicle tests. Among the main sticking points were what to do when approaching a yellow light, and the safe distance to maintain behind another car.
Overall, the national average score grew slightly to 78.1% from 77.1% in 2007, but scores varied based on driver demographic and geography.
The study found that drivers over the age of 35 were more likely to pass, and women were more likely to fail than men.
Drivers in the Northeast continued to have the lowest scores and the highest failure rates, with New York, New Jersey, Massachusetts, and the District of Columbia maintaining their three-year streak in the bottom five rankings. Drivers from the Midwest had the highest scores and the lowest failure rate, with Kansas taking the top spot this year from Idaho.
"It's encouraging to see that scores are beginning to get better, but there is still a lot of room for improvement," Wade Bontrager, GMAC Insurance's vice president of marketing said in a statement.
Some of the bright spots showed that nearly all of the test-takers knew how to respond to an emergency vehicle with flashing lights, what to do when hydroplaning, and how to interpret a solid yellow line.
How well do you know the rules of the road? Take the test. 
