In shorts and a T-shirt on a sweltering afternoon, a man walked in a white-painted crosswalk bridging four lanes of Yulupa Avenue traffic at Princeton Drive.
A tan van flew through the intersection, just missing the man, who threw up his arms, aghast.
"Most people who don't stop don't even see him," said Sgt. Mike Numainville, perched on a motorcycle in the shade several yards away.
A nearby officer in a marked patrol car started his sirens and pulled the van over.
The team of officers was part of a two-week effort to focus on motorists' dangerous behavior toward pedestrians, as well as on people on foot who shirk traffic laws.
The walking man was Officer Jeff Adams, dressed for his role as a regular citizen, who spent the day stepping through some of the city's trickiest crossings.
"Collisions with pedestrians — it's an issue we felt needed extra focus," Numainville said.
Nineteen pedestrians have been killed by motorists since 2011 in Sonoma County, including 11 in Santa Rosa, according to Press Democrat records.
Seven of Santa Rosa's 11 fatal collisions were the fault of the pedestrians, according to the police investigations.
"Drivers aren't watching out for pedestrians, and pedestrians aren't watching out for drivers," Numainville said.