(AP) — A 37-year-old Illinois truck driver has been given 20 years in prison for a crash in Nebraska last year that killed a Maryland family.

Josef Slezak was sentenced on Wednesday in Sidney. Slezak, of River Grove, Ill., had pleaded no contest to four counts of vehicular homicide and one count of vehicular homicide involving an unborn child. Prosecutors dropped four manslaughter counts in exchange.

Authorities say Slezak had been driving virtually nonstop from Milwaukee, Wis., and was in western Nebraska on Interstate 80 when he fell asleep at the wheel on Sept. 9, 2012. His semitrailer slammed into the back of a car, killing Christopher Schmidt, his wife, Diana Schmidt, and their children ages 2 and 3. Diana Schmidt was 30 weeks pregnant.

The Schmidts were from Gaithersburg, Md.