A government report says the number of drivers under the influence of alcohol has declined since 2007. According to the National Highway Traffic Safety Administration, the share of drivers who test positive for alcohol has declined by more than three-quarters since the agency first began conducting roadside surveys in 1973. But, AP reports, the latest survey found that nearly 1 in 4 drivers tested positive for at least one drug that could affect safety. The data is gathered in dozens of locations across the country.