Gwen Vierra has a message for seniors about to graduate from high school: Bad things can happen to good kids.

Her son, Lanakila, a bright, popular student-athlete at Waialua High School who had been accepted to the University of Washington, was 12 days away from his 18th birthday in 2006 when he and a classmate died in a car crash on Kaukonahua Road.

"This is tough," she said. "Not a day goes by that we don't miss him."

Starting today, Honolulu police will set up roadblocks, kicking off a stepped-up enforcement campaign to encourage young people to drive safely this summer. The checkpoints and increased police presence on busier streets will last through Labor Day, police said at a press conference announcing the effort and featuring Vierra.

Memorial Day weekend marks the start of the "101 deadliest days on the roadways," when high school seniors are celebrating graduation, and both high school and college students are on summer vacation, said Maj. Frank Fujii, HPD spokesman.

O'ahu has seen 16 traffic deaths this year, compared with 34 at this time last year. Alcohol was a factor in at least four of this year's incidents.

Fujii attributed the lower number of fatalities to increased efforts to spread the word about the dangers of speeding and drunk driving.

"People are beginning to hear the message," he said.

HPD is also continuing the federal "52/12" sobriety checkpoint program. From Oct. 1, 2007, to Sept. 30, 2008, police have been conducting at least one sobriety checkpoint each week.

Vierra and other residents will be sign-waving near Hale'iwa Beach Park from 10 a.m. to 2 p.m. Saturday to remind motorists about driver safety.

Since her son's death, Vierra has encouraged students to take simple steps while driving, like using turn signals. She said she wants parents to remind their children that they can always call them for help if they feel they're in trouble.

Early on the morning of May 14, 2006, Lanakila Vierra, Shane Bachiller, 18, and three others were returning from celebrating Bachiller's birthday when their car crashed along a winding stretch of Kaukonahua Road. Bachiller was pronounced dead at the scene and Vierra died at The Queen's Medical Center later that day.

The driver in the crash will be arraigned June 5 on two counts of second-degree negligent homicide and one count of first-degree negligent injury.

Billy Joeson Lamug was indicted April 3 by an O'ahu grand jury. He is living in Phoenix and plans to return to Honolulu for his court appearance, authorities said.

It was a tragic year for the Waialua High School senior class. Five months after the accident, the boys' classmate, 18-year-old Bobby Gouveia of Waialua, was killed when his car veered across the center line of Farrington Highway and struck a utility pole and a fence.

Gwen Vierra moved from Waialua to Hale'iwa after her son's death. But she has not forgotten that terrible summer and the accident on Kaukonahua Road.

Her youngest son, Koa, 17, is about to graduate from Waialua High School. Vierra said her son "has learned a lot" about responsibility since his brother's death.

"Choices, choices, choices," she said. "You have the right to make that choice."

Staff writer Rod Ohira contributed to this report.