LOS ANGELES, CA – A 55-year-old motorcyclist was killed Wednesday morning after being struck by a driver who was later arrested on suspicion of driving under the influence in Lake Forest, authorities said.
The collision was reported at approximately 5:42 a.m. on Aug. 19 near El Toro Road and Creekside, according to the Orange County Sheriff’s Department.
Deputies arriving at the scene found the motorcyclist, identified as David Matthew Atwood Sr., 55, of Lake Forest, unresponsive.
Atwood was transported by the Orange County Fire Authority to a local hospital, where he was pronounced dead.
The driver involved in the collision was identified as Matthew Christian Biedebach, 21, also of Lake Forest.
Authorities said Biedebach was arrested on suspicion of driving under the influence and booked into the Orange County Jail.
The Sheriff’s Department has not publicly released additional details about what led to the collision, including the direction each vehicle was traveling, the point of impact or whether speed played a role.
Authorities also have not disclosed what substance Biedebach is suspected of being under the influence of.
Under California law, DUI can involve alcohol, drugs or a combination of both. The California Department of Motor Vehicles states that it is illegal to operate a vehicle while impaired by alcohol or any drug that affects a driver’s ability to operate safely.
For drivers age 21 or older, California law sets a blood alcohol concentration limit of 0.08%, though a driver can still face DUI allegations at a lower level if other evidence shows impairment.
The Sheriff’s Department has not released Biedebach’s blood alcohol concentration or said whether investigators suspect alcohol, drugs or both.
His arrest represents an allegation, and he is presumed innocent unless and until proven guilty in court.
Roads around El Toro Road and Creekside were closed temporarily while deputies investigated the crash and crews worked to clear the scene.
Authorities have not said how long the closures remained in effect.
The fatal collision is being investigated by the Orange County Sheriff’s Department’s Major Accident Investigation Team, or MAIT.
The specialized unit handles serious and fatal traffic collisions in areas served by the Sheriff’s Department and works to determine factors including vehicle movements, roadway evidence and possible impairment.
The department confirmed MAIT is leading the investigation into Atwood’s death and is asking witnesses or anyone with additional information to contact investigators at 949-425-1860.
The collision occurred less than two weeks after another fatal suspected-DUI crash in Lake Forest.
On Aug. 6, deputies responded to a two-vehicle collision at El Toro Road and Via Ridgeline Road in which a man in his 70s was killed.
In that case, a 22-year-old Lake Forest driver was arrested on suspicion of DUI and booked on suspicion of gross vehicular manslaughter while intoxicated, according to an Orange County Sheriff’s Department release.
Authorities have not suggested the two crashes are connected.
The Aug. 19 collision also comes amid broader concerns about impaired driving and motorcycle fatalities in California.
The California Office of Traffic Safety reported that 583 motorcyclists were killed in crashes statewide in 2023.
The agency says motorcycle safety efforts focus both on rider behavior and on other motorists, including enforcement against speeding, unsafe turns, red-light violations and failure to yield.
Motorcyclists are especially vulnerable in collisions because they lack the protective structure of passenger vehicles.
That broader safety context does not establish fault in Wednesday’s crash, which remains under investigation.
Statewide, the Office of Traffic Safety also reported 1,355 fatalities in crashes involving a driver or motorcycle rider with a blood alcohol concentration of 0.08% or higher in 2023.
Those figures are statewide statistics and do not indicate the circumstances of the Lake Forest case.
Investigators have not announced whether additional charges could be considered against Biedebach.
A DUI arrest following a fatal crash does not automatically determine what criminal charges prosecutors may ultimately file.
Charging decisions can depend on toxicology results, collision reconstruction, witness statements and other evidence developed during the investigation.
The Sheriff’s Department has not released information about whether surveillance cameras or dashcam footage captured the collision.
Authorities have also not said whether additional witnesses were interviewed at the scene.
Atwood’s death remains under active investigation.
Anyone who witnessed the collision or has information that may assist investigators is asked to contact MAIT at 949-425-1860.
Anonymous tips can be submitted through Orange County Crime Stoppers at 1-855-TIP-OCCS (1-855-847-6227). The organization says tips can be submitted without providing identifying information.
No additional information about the crash was immediately released.
