The average American is spending about 36 hours a year in traffic, up from 11 hours in 1982, according to a study released today by the Texas Transportation Institute at Texas A&M University. Based on 1999 data, the most recent year for which such figures were available, the report found that the average Los Angeles resident spent 56 hours a year in traffic; Seattle and Atlanta tied at 53 hours; Houston came in at 50 hours; Dallas and Washington, 46 hours; Denver and Austin, 45 hours; St. Louis, 44 hours; and Miami, 42 hours. Trips in the car during rush-hour traffic took fully twice as long in Los Angeles as those during non-rush-hour traffic. The study said that 6.8 billion gallons of gasoline were wasted in traffic in 1999.