Of those surveyed, 1.8 percent said they were involved in at least one instance of driving under the influence, for a total of about 112 million incidents alcohol-impaired driving in 2010, down from 161 million episodes in 2006.

“Reasons for the decline in alcohol-impaired driving are not well understood, but possible factors include less discretionary driving as a result of the current economic downturn … and possible changes in drinking location to places where driving is not required such as at home,” the center said in the conclusion of its survey, citing two sources of outside research.