SAN DIEGO -- Family and friends of a teenage East County teen killed in an unsolved car-to-car freeway shooting 17 months ago will gathered Saturday for a vigil on what would have been his 18th birthday.

The late-morning memorial for Brandon Johnson of Lemon Grove, who was slain along with his best friend on state Route 54 in Bonita, will take place in front of the Chula Vista bowling alley the youths visited the night of their deaths.

Brandon, then 16, was riding in an Acura sedan with 15-year-old Donnell Davis Jr. of San Diego and several other companions when another eastbound vehicle pulled up alongside them and someone inside it opened fire shortly before midnight March 16, 2008, according to sheriff's homicide officials.

The Acura's driver suffered non-fatal gunshot wounds and lost control of the car, which crashed into a concrete divider wall and overturned. Brandon and Donnell died at the scene.

The driver of the other vehicle sped out of the area before emergency crews arrived.

Authorities have released no suspect information in the case and have disclosed no possible motive for the shooting.

San Diego County Crime Stoppers is offering a reward of up to $1,000 for information leading to an arrest in connection with the slayings. The nonprofit agency's tip number is 888-580-8477. Callers may remain anonymous.