The September crash that killed two Minnetonka High School seniors in rural Carver County may have been caused by the driver losing control because she was using an electronic device, the sole survivor has told authorities.

Mitchell Grengs, 17, who suffered serious injuries in the crash, was recently interviewed by a State Patrol investigator. Grengs was riding with his cousin, Kylie Grayden, the driver, and her friend Kelly Phillips, both 17, to a farm bonfire the night of Sept. 21. Grayden and Phillips died.

Grengs initially told the patrol that he thought his cousin was using her iPod or cell phone before going off the road. When pressed, Grengs said he thought it was the iPod, said Nathan Bowie, a patrol spokesman. He said the case is still under investigation. Grengs, whose Facepage shows him wearing a halo contraption to stabilize his neck injury, could not be reached for comment Wednesday.

"Teens being distracted is a significant issue, particularly because they are not experienced drivers," said Cheri Marti, director of the state Office of Traffic Safety. "Text-messaging, getting cell calls, listening to an iPod, talking with friends in the car -- it increases the risk of a crash."

A 2006 state law prohibits teenagers under 18 with a driving permit or provisional license in a moving vehicle from using a cell phone, even with a headset, except in emergencies.

Marti said parents should model safe driving and set clear rules for teens about wearing seat belts, not speeding or using cell phones and minimizing night driving.

Grengs and Grayden were wearing seat belts. Phillips, who wasn't, was ejected from the back seat. Patrick Grengs, Mitch's father, has said that a seat belt saved his son's life.

Marti noted that a study in the American Medical Association journal found that a 16-year-old driver increased the risk of a fatal crash by almost 40 percent with one friend in the car. With two teen friends, the risk jumps by 86 percent, and with three, by 282 percent.

Although using electronic devices while driving is distracting, Bowie said it is difficult to track how often using such devices causes crashes.

He noted that a trooper stopped a teenage driver going 106 miles an hour in July near Mankato. The driver, a 16-year-old Minnetonka girl, told the trooper she was lost and didn't know how fast she was going because she was text-messaging her boyfriend to get directions to his home in St. James.

Bowie said troopers handled at least four other cases this year in which the drivers admitted or were seen using cell phones shortly before they were stopped or crashed. Two of the drivers said they were text messaging and all four were arrested for drunken driving, Bowie said.

A Department of Public Safety study done in August of observed hand-held cell phone use in Minnesota found that about 4.5 percent of drivers are using a cell phone at any time during daylight hours. The report noted that three states -- New York, New Jersey, Connecticut -- and the District of Columbia have restricted cell-phone use by drivers. Colorado has banned cell-phone use by teens while driving.

Jim Adams • 612-673-7658

Jim Adams • jadams@startribune.com