Washington ? High school senior Gabriela Sazon is a walking advertisement for teens wearing seat belts: She and her mother escaped injury two years ago when their car flipped on a rain-slick road. Both were buckled in.

But she also understands the difficulty in getting fellow Coolidge High teenagers to fasten their belts: “They don’t want to seem like a nerd around their friends.”

More than two-thirds of young drivers and passengers killed in nighttime car crashes weren’t wearing seat belts, the government reported Monday – deadly proof of what can happen when young people don’t heed parents’ pleas and authorities’ threats to “click it.”

Though seat belt use actually is rising slightly nationwide, the fatality figures offered a somber contrast as law enforcement launched its annual pre-Memorial Day drive to persuade Americans to buckle up.

Total belt use rose to 82 percent last year – from 81 percent in 2006 – the government said. But the news was hardly all encouraging.

Sixty-eight percent of drivers and passengers between the ages of 16 and 20 who were killed in car crashes at night in 2006 were unbuckled, said the National Highway Traffic Safety Administration. During daytime, 57 percent of the young motorists and passengers who were killed were not wearing seat belts.

That portion of the study focused on 2006 data and did not evaluate other years.

The problem isn’t just with teens. The percentage of unbuckled drivers and passengers who died at night is well up in the 60s through the age of 44. It declines to 52 percent for people 55-64 and 41 percent for those older than that.