Between 9 a.m. and 7 p.m., officers responded to nine car-related crashes, six of which were non-injury and one that seriously injured a pedestrian.
The first crash was reported at 2:05 p.m. in the 2100 block of Petaluma Boulevard North.
Arriving officers discovered Jorge Milan, 62, of Petaluma, had apparently driven his red Toyota 4Runner off the right-hand shoulder and crashed into and completely destroyed a business sign displayed on large posts inside a planter box, Petaluma police said.
He also appeared to have struck one parked car that then rammed through a wooden fence, which then damaged three more parked cars, according to police.
Officers believe Milan was under the influence of prescription medication and marijuana. He was arrested on suspicion of DUI, police said, and he did not have prior DUI offenses on his record.
Milan was not injured in the crash.
About an hour later, officers were dispatched to a solo-vehicle crash on North McDowell Boulevard, where Nicholas Llamas, 20, of Petaluma, appeared to have been driving north when he attempted to pass another car over the railroad grade crossing, police said.
It was then that he lost control of his car and struck a tree. The crash blocked both northbound lanes and caused an oil spill that needed to be cleaned before the roadway could be reopened, according to police. The road reopened at 5 p.m.
The driver sustained moderate injuries and was taken to a hospital, police said.
A third incident reported at 6:06 p.m. appeared to be an injury crash between a vehicle and a pedestrian on South McDowell Boulevard in front of a Safeway supermarket, police said.
Police said Todd Schwenn, 17, from Petaluma, was driving his blue Buick sedan north on South McDowell Boulevard in the left lane when Thomas Foakes, 30, of Petaluma, was walking west in the crosswalk at the intersection of McNeil Avenue and the Washington Square Shopping Center.
According to police, Schwenn's car struck the pedestrian, who then hit the hood and windshield before going over the top of the car and landing in the roadway about 75 feet north of the crosswalk.
Foakes sustained severe injuries and was taken to the hospital, police said.
Investigators are hoping to learn more about the incident and ask anyone with information to call Petaluma police Officer Walt Spiller at (707) 776-3720 and mention report No. 12-000302.
As of Friday night, Foakes was listed in serious but stable condition, police said.
Officers later learned that Schwenn had received his driver's license in the past two weeks. Alcohol does not appear to be a factor in the crash, according to police.
Northbound McDowell Boulevard between McNeil Avenue and East Washington Street remained closed until 8:30 p.m., police said.