ESCONDIDO (CBS 8/CNS) - A motorist who was allegedly under the influence of some type of drug when his SUV struck and killed a 21-year-old Caltrans subcontractor as he worked alongside a freeway on-ramp in Escondido was behind bars Tuesday.

Oceanside resident Reginald Grigsby, 31, apparently lost control of his Mitsubishi Montero as we was attempting to transition from southbound South Centre City Parkway onto southbound Interstate 15 shortly after 2 p.m. Monday, California Highway Patrol Officer Jim Bettencourt said.

The SUV veered off the roadway, rolled down an embankment and struck the victim as he was working on a sprinkler system in a median next to the freeway entrance. The worker, who was killed instantly, is identified as 21-year-old Leonardo Sandoval. Bettencourt said that Sandoval, from Murrieta, is an employee of Perris-based Pacific Restoration Group. According to Caltrans Director Laurie Berman, Sandoval leaves behind a small son and was engaged to be married next spring.

The SUV overturned before coming to rest on its roof next to a northbound offramp from I-15. Caltrans closed that connector to through traffic to allow for investigation and cleanup.

Grigsby suffered minor injuries in the crash and was taken to Palomar Medical Center, where he was placed under arrest, Bettencourt said. He was later booked into the Vista Detention Facility on suspicion of felony DUI and vehicular manslaughter, according to the CHP and jail records.

Statement from Caltrans

The Caltrans Family mourns the tragic loss of contractor’s employee Leonardo Sandoval. Mr. Sandoval worked for Pacific Restoration Group and was repairing sprinklers along a stretch of Interstate 15 in Escondido on Monday afternoon when he was struck and killed by a car driven by a man who was later arrested for being under the influence of drugs and felony vehicle manslaughter.

Words cannot express the emotions regarding this totally preventable loss of life. Mr. Sandoval, age 21, was described by his co-workers as an “awesome kid,” who had a small son and was engaged to be married next spring. Our thoughts are with his family, friends and co-workers during these unimaginable times. We will update you when funeral arrangements are announced and of any fundraisers.

We remain ever vigilante in our efforts to educate the motoring public on the life-altering consequences of driving under the influence and distracted driving. This is a stark reminder of the dangers of working along our highways.

-- Caltrans District 11 Director Laurie Berman