If you spend any amount of time behind the wheel, the results of a recent national drivers test should scare you. And if they don’t, they should.

In late May, GMAC Insurance reported that nearly 1 in 5 drivers -- or about 38 million Americans -- could not pass a written drivers test if they took it today.

That’s according to the insurer’s annual National Drivers Test survey, which was conducted by polling 5,202 licensed drivers from 50 states and the District of Columbia. The survey posed 20 questions that were culled from various state Department of Motor Vehicles exams.

The general upshot of the results is that a shocking number of licensed American drivers continue to demonstrate a woeful lack of knowledge when it comes to the basic rules of the road. The national average score for the latest survey dropped slightly from 2009 -- from 76.6 percent to 76.2 percent. In ’07, the average score was 78.1 percent, says Wade Bontrager, senior vice president of GMAC Insurance.

If respondents got less than 70 percent correct, that was considered a “failing” score. Pedestrians also have every reason to be afraid -- very afraid -- after hearing that fully 85 percent of those surveyed could not accurately identify the proper action to take when coming up on a yellow traffic light. Especially since one of the “answer options” for the question was: “Go through the intersection before it turns red.”

Also, 73 percent did not know the safe following distance, says Bontrager -- not surprising, given how often we see high-speed tailgating on any freeway in any major metropolitan area during rush hour. The correct answer is actually not measured in distance, but in time. “You need three seconds to come to a safe, complete stop,” said Bontrager. “So, the actual distance you travel during those three seconds depends on how fast you’re driving.

"It’s very discouraging that overall test scores are lower than last year’s,” Bontrager said. "Driving safety must be a top priority, and drivers just have to be aware of the rules of the road at all times.

“Being an insurance company, we see, every day, what happens when people make mistakes on the road -- they end up in accidents, some of them very serious -- and these are accidents that could have been avoided if they followed these rules,” muses Bontrager. “Decisions made in a split-second can determine whether or not you’re able to avoid an accident.”

GMAC began conducting the survey six years ago as a way of raising awareness of the importance of driving safety, and to “spark interest” in drivers improving their knowledge, he says.

The survey tabulates the results regionally as well as on a state-by-state basis and ranked the states in terms of their average scores. Respondents in the Northeast lagged behind their Midwestern motoring brethren. The Northeast had the lowest average test scores -- 74.9 percent -- and the highest failure rate, at 25.1 percent.

Meanwhile, the Midwest region had the highest average test scores -- 77.5 percent -- and the lowest failure rate, at 11.9 percent.

And when ranked on a state-by-state basis, New York drivers were cellar-dwellers. Drivers in the Empire State ranked dead last, with an average score of 70 percent -- just barely a passing grade.

And, what state ranked Number One? That would be Kansas, with an average score of 82.3 percent.

Still, even that 80-percent-plus score in the Jayhawk State is nothing to shout about, because that translates into 20 percent of the drivers surveyed not having enough basic driving knowledge. “Until we start seeing scores of 95 or 100 percent coming out of every state, we still need to see a lot of improvement, across the board,” says Bontrager.

And isn’t just a lack of knowledge that concerns driving-safety experts.

Russ Rader, a spokesman for the Insurance Institute for Highway Safety, also laments the careless disregard for basic driving rules even by those drivers who do know the rules. “Drivers do need to know the basic rules of the road, but knowing them isn’t the same as obeying them,” said Rader. “Even when we know the speed limit, for example, we still break it. That’s why speeding is a factor in a third of all highway deaths,” adds Rader.

“Drivers also know they shouldn’t run red lights,” yet hundreds of people are killed and thousands are injured by red light runners every year, notes Rader -- who adds that motorists also know that cell phones are a distraction, yet they continue to yak into their phones while driving. “Our highways are a lot like Lake Wobegon (the fictitious town created by NPR's Garrison Keillor) -- most drivers think they’re ‘above average’; it’s all the other ‘idiots’ out there that need to hit the books.

“Research shows that law enforcement (in the form of traffic tickets) may be the best driver education program yet invented.” On the GMAC National Driver’s Test, there was also a “gender gap” of sorts -- men had a higher average score than women -- 78.1 percent, compared to 74.4 percent. The gap was wider when it came to the failure rate -- 24 percent for women, versus 18.1 percent for men.

And, overall, among survey respondents, a significantly higher percentage of women, compared to men, engaged in various "distracted driving" behaviors, like talking on cell phones, adjusting the radio, eating, fiddling with their iPods or applying make-up -- the latter of which is obviously a more gender-specific activity. (Generally speaking, anyway.)

Overall, fully 25 percent of those surveyed said they engaged in these kinds of distracted driving behavior. This was the first year the survey included distracted-driving questions, so there’s no way of knowing whether there was an increase or decrease in this kind of behavior in 2010, compared to previous years.

“But 25 percent is way too high,” admonishes Bontrager.

One consolation is that only five percent said they texted while driving, which suggests that state laws against this wildly dangerous practice -- as well as TV-public-service announcements warning about its hazards -- are having some impact.

So, do you think you’re smarter than the average driver when it comes to knowing the rules of the road? You can find out by going to www.gmacinsurance.com, where you can take the test, see the full state-by-state rankings, play a driving game, and challenge friends to top your score.

Also, Facebook users can go to National Drivers Test Facebook quiz and challenge their FB friends, while Twitter users can follow the Drivers Test Twitter page for updates on state rankings and get some tips on safe driving habits.

Top Safety Picks 2010 from the Insurance Institute for Highway Safety
LARGE CARS
Buick LaCrosse
Ford Taurus
Hyundai Genesis (built after 1/2010)
Lincoln MKS
Mercedes E class (built after 1/2010)
Volvo S80

SMALL CARS
Honda Civic (4-door (except Si) with optional ESC)
Kia Forte (built after 10/2009)
Kia Soul
Nissan Cube
Scion xB
Subaru Impreza (except WRX)
Toyota Corolla
VW Golf (4-door)

MIDSIZE CARS
Audi A3
Chevrolet Malibu (built after 11/2009)
Chrysler Sebring (4-door w/optional ESC)
Dodge Avenger (with optional ESC)
Hyundai Sonata (2011 models)
Mercedes C class
Subaru Legacy
Subaru Outback
Volkswagen Jetta (sedan)
Volkswagen Passat (sedan)
Volvo C30 (2010-11 models)
MIDSIZE SUVs
Dodge Journey
Subaru Tribeca
Volvo XC60
Volvo XC90

SMALL SUVs
Honda Element
Jeep Patriot (w/optional side torso airbags)
Subaru Forester
Volkswagen Tiguan