Hawaii drivers are among the least knowledgeable about the rules of the road, according to a study by GMAC Insurance.

According to the results of the GMAC Insurance National Drivers Test, Hawaii ranked 50th in the nation with an average score of 73 percent correct.

Only drivers in Washington D.C. are less able to pass a drivers license test. Drivers in the nation’s capital scored an average of 71.8 percent on tests, the insurer said.

The national results show that almost one in five drivers, or 36.9 million U.S. motorists, “cannot meet the basic requirements” to get a license, according to the statement. The test of 20 questions from licensing exams was given to 5,130 drivers from all 50 states and the capital.

“Taking the test brings a little bit of attention to something that people don’t generally think about,” said Scott Eckman, GMAC Insurance’s chief marketing officer, in an interview. “If we can have people just think twice, it may make them think about rules and maybe pay attention.”

Eighty-five percent of drivers couldn’t identify the correct action to take when approaching a steady yellow traffic light. Correct answer: “Stop if it is safe to do so,” according to a version of the test on GMAC Insurance’s website.

Some of the test results may be explained by people learning to drive from family members, Jean Guenguem, co-owner of Dexterity Driving School in the capital, said in a phone interview. Drivers should brush up on the rules every two years, he said.

The national average rose from 76.2 percent in 2010. New York, Mississippi, Massachusetts, New Jersey, and Maryland motorists are also at the bottom of the list. Kansans ranked No. 1 with 82.9 percent. The test was given online by the insurer through a research company to licensed drivers, ages 16 to 65.

 The national average for the test was 77.9 percent, with below 70 considered failing.