EL PASO COUNTY, Colo. -

A southern Colorado woman who dedicates her life to promoting responsible driving says she's saddened and disappointed to hear about a deadly crash involving teenagers in Monument.

Early Monday morning, a 17-year-old Monument teenager was driving with three of his friends when he ran a stop sign, lost control and crashed. 17-year-old Beau Begier and 18-year-old Ryan Pappas were killed and a third passenger remains in the hospital in serious condition.  The driver was under the influence of alcohol, according to investigators, and faces charges of vehicular homicide and vehicular assault.

"It's a very sad feeling I have for them," said Sheyna Marshall. "I look at the teenagers that lost their lives and I know exactly the feelings the families are going through right now."

Marshall knows the pain because she's been there.

On Memorial Day in 2006, Marshall, her husband and three kids were on their way home from their favorite restaurant in Waldorf, Maryland.  They were stopped at a red light when two teenagers who were drag racing collided into each other then into the Marshall family's vehicle.  The teens were traveling at speeds up to 90 MPH.  Marshall's 6-year-old son, Christian Marshall, was killed instantly.  Her younger son, Justin Marshall, suffered a severe traumatic brain injury and her 2-year-old daughter suffered broken bones.

"In a heartbeat, in a second, everything can change," Marshall said. "I didn't believe it really could truly happen to me, but it did. And that's my point, it can. I had my family there one instant and the next instant it was decimated. My family was wiped out."

Over time, Marshall found ways to heal. She became a police officer and is now a detective with the Fountain Police Department.  She also volunteers her time speaking at area schools about safe driving and the importance of making responsible decisions.

"I have made it my life's mission: Bring something good out of the bad," Marshall said. "I tell my story. I show them what reality is. I show them my son's hand hanging out of the window as they're cutting him out of the vehicle moments after he passed away from being so severely injured."

Marshall said another point she stresses to teens is that you don't have to be a victim.  If you are a passenger in a vehicle with an unfit driver, you have the power to say something -- whether it's telling them you don't approve of their driving, refusing to accept a ride or telling a parent or police officer. 

"If you don't like the way somebody's driving, say something," Marshall said. "I'd rather have them get in trouble with the cops and go home at the end of the night, than somebody knocking on a parent's door saying, 'Hey, guess what. I'm sorry I have to inform you of this.'"

Marshall also said that 90 percent of all crashes involve human error and are, therefore, preventable. She hopes her family's story inspires all drivers to choose to not speed, drive drunk or distracted.

Through Drive Smart Colorado, Marshall presents her story and "Christian's Challenge" to schools around southern Colorado. If you're interested in contacting Marshall to speak at your child's school, you can find more information here.