Virginia has the toughest written driving tests in the country, according to a study by the Whitley Law Firm, a personal injury firm, and Journo Research. States the press release:

Virginia is the state where it’s hardest to pass the written driving test, with an index score of 21.39 out of 100. To pass the 35-question exam, one must score at least 86%, meaning examinees must answer at least 30 questions correctly. In addition, there needs to be a 15-day gap between one test and the next if participants were unsuccessful the first time around. 

New York has the easiest written test, according to the study.