ORANGE COUNTY, Calif. — The brain of a teenager is a work in progress.

“The social centers develop faster than the executive center,” said Dr. Almaas Shaikh, trauma director of Mission Hospital in Mission Viejo. She tells me that the pre-frontal cortex, the part of the brain responsible for weighing outcomes and controlling impulses, may not be fully formed until the mid-20s. It’s this brain that is taking the drivers exam at the DMV, saying yes or no when a friend offers a beer, and possibly getting behind the wheel after having a drink.

“It’s so easy to be intoxicated and get into a tricky situation because you’re not really there,” said Kayla Machingo. A recent high school graduate, Machingo is a volunteer with the Safe Rides program, providing free, confidential rides to teens on Friday nights October through June. She tells me about Instagram accounts that promote weekend party locations and the very real teenage need to feel cool and included.

“I just want to raise awareness,” she said. She rattles off facts with ease, telling me that teens are 17 times more likely to die in a crash when they’ve been drinking.

“I have friends with DUIs,” she said. “It has affected their friends, their family. Drinking and driving is not just about one person.”

According to statistics gathered on the Mothers Against Drunk Driving website, more than 40 percent of all 10th-graders drink alcohol, and kids who start drinking young are seven times more likely to be in an alcohol-related crash. One in seven teens binge drink, yet only one in 100 parents believe their kids binge drink. Understanding that teens are wired for pleasure, not reason, might prompt the other 99 parents to start a conversation.

“It is never too early to begin talking about drinking,” Shaikh said. She tells me that many parents don’t broach the subject for fear that they will provoke an interest in alcohol. “But it’s our job to guide our kids toward safe and healthy choices.”

There are many ways to begin the conversation. Shaikh suggested taking a look at the media, where alcohol has a starring role in advertising, movies, television shows and music. “Begin to parse these messages.”

Machingo’s mom, Kris Machingo, is a nurse at Mission Hospital. She said she’s always been honest with her daughter about the dangers of drinking and urged Kayla to volunteer at the hospital. The experience has been an education and a self-esteem builder. “Building up a kid’s self-confidence encourages them to trust their gut,” Kris Machingo says. At a time when peer pressure is at its peak, parents should try to “make the kids think for a second.”

According to the Centers for Disease Control and Prevention, most teens drink to get drunk. The organization’s website suggests that parents talk to their kids about zero-tolerance laws, which make it illegal for those under 21 to drive after drinking any alcohol. Parents can create a “parent-teen” driving agreement using the template at cdc.gov/parentsarethekey. Use this tool to set limits on driving time, number of passengers, cellphone use and, of course, drinking.

Shaikh suggests that parents get to know their teen’s friends and the parents of those friends. She also stresses the need for parents to model responsible behavior such as planning for a designated driver. Prompt kids to call for a ride no matter what.

Kris Machingo agreed. “I want my daughter to know that safety comes before anything else. She knows I trust her to make the right decision, but she also knows that if there’s a problem, she can call me.”

Shaikh believes that a hospital trauma bay is a mirror of what’s going on in the community. “In the O.C.,” she said, “we’ve got elderly falls and teens driving under the influence.” Trauma is preventable.

“Bottom line,” she said, “it’s about helping kids know they can make the right choice.”