PASO ROBLES, Calif. -- Two California Highway Patrol officers were struck and killed on roadsides Sunday, bringing to five the number of CHP officers killed in the line of duty in less than two months.

Officer Brett Oswald, 47, of Paso Robles was killed while waiting for a tow truck to remove an abandoned car from a road near Paso Robles in San Luis Obispo County.

A woman lost control of her Toyota Corolla and rear-ended his patrol car, CHP and county sheriff's officials said.

Oswald, a 21-year CHP veteran, was hurled into the air and landed on the woman's car, authorities said.

There was no immediate citation or arrest.

Hours earlier and about 200 miles away, CHP officer Justin McGrory, 28, was killed after being hit by a car during a traffic stop on the northbound 15 Freeway in Barstow.

McGrory had pulled a vehicle over for speeding at 3:38 a.m. Sunday and was conducting a field sobriety test when he was hit by a red 2009 Pontiac G6 that veered onto the right shoulder.

He was airlifted to Saint Mary's Hospital, where he died of his injuries.

The driver, identified as 18-year-old Rafael Garcia, of Las Vegas, stopped a short distance away from the crash.

He was arrested for vehicular manslaughter.

McGrory, from Victorville, had been a CHP officer since 2007. He leaves behind a wife and three young children, ages 7, 4 and 1.

Gov. Arnold Schwarzenegger issued separate statements upon learning of each officer's death.

"Officer Oswald was a real hero; one of California's bravest.

He risked his life day in and day out to protect the safety of Californians," Gov. Schwarzenegger said in a statement Monday.

On Sunday, Schwarzenegger addressed McGrory's death, saying, "Maria and I were deeply saddened to learn of the tragic death of CHP Officer Justin McGrory.

He was selfless and dedicated, and committed his life to protecting the safety of all Californians.

We extend our thoughts and prayers to Justin's family, loved ones, and the entire Victorville community as they mourn the loss of a father, son and outstanding officer."

McGrory and Oswald are among four CHP officers killed in the line of duty this month, and five in the past two months.

CHP motorcycle officer Tom Coleman was killed June 11 in a pursuit-related crash in Redlands.

Fellow CHP motor officer, Philip Ortiz, died two weeks after being struck by a sport utility vehicle during a June 9th traffic stop on the 405 Freeway.

CHP Officer Daniel Benavides was killed in a plane crash in Imperial County on May 7.