A Twin Cities man now with 18 convictions for driving under the influence dating to 1979 has been sentenced to prison for being high on illicit drugs when he triggered a four-vehicle crash in southern Dakota County that seriously injured a Rochester couple.

Marshall A. Knoll, 60, of Rosemount, was sentenced in District Court last week by Judge Cynthia McCollum to a three-year term in connection with the wreck on Oct. 20, 2017, at Hwy. 52 and E. 210th Street in Vermillion Township.

With credit for time in jail since his arrest, Knoll will serve 20 months in prison and another five years under court supervision.

Knoll pleaded guilty earlier to first-degree driving while impaired. In exchange, two more serious counts of criminal vehicular operation and one count of driving after his license was canceled were dismissed.

"We are pleased to have brought Marshall Knoll to justice for causing this crash while driving impaired once again," County Attorney James Backstrom said after sentencing. "We wish the victims well in their continuing recovery."

The analysis by the state Bureau of Criminal Apprehension revealed the presence of amphetamine and methamphetamine in Knoll's blood.

At the time of the crash, the state had canceled his driving privileges.

A woman in the car that Knoll struck, Karpagam Maran, 58, suffered a broken sternum and fractured ribs, a broken arm and bleeding on the brain. The driver, Avudaiappan Maran, 60, required surgery to his spine.

According to the prosecution, witnesses saw a truck pulling a trailer on northbound Hwy. 52 that was traveling erratically and speeding. Traffic stopped, but Knoll's truck did not, and his vehicle rear-ended the other vehicle at 50 miles per hour.

Officers at the scene noticed that Knoll had bloodshot and watery eyes, slurred speech and lethargic movements and was unsteady on his feet. A blood sample revealed the drugs in his system.