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.

During the operation, which ran through the end of June, Santa Rosa police cited 57 drivers for violating the right-of-way of pedestrians.

Officers also gave 17 pedestrians citations for a range of violations, including jaywalking and crossing against red lights and don't-walk lights.

They also handed out more than 100 pamphlets about pedestrian safety.

<NO1>Traffic officers spent the two week<NO><NO1>s on patrol focusing on these violations. <NO>For three days during the two-week period, an undercover officer walked through crosswalks as uniformed officers watched how motorists reacted.

<NO1><NO>The Petaluma Police Department, Rohnert Park Public Safety Department, CHP and Santa Rosa Junior College Police provided officers for the three days.

On June 28, groups of officers spent time at the Yulupa Avenue crossing and five others across the city:

--Summerfield Road and Wyoming Drive;

--Hoen Avenue and Sierra Creek Lane;

--West Third Street and Brockhurst Drive;

--McMinn Avenue and Sebastopol Road;

--Mendocino Avenue and Benton Street.

Behind the wheel of the tan van that zoomed past Adams, an 18-year-old driver told an officer she was practicing speaking Spanish with her mother and didn't see the man in the crosswalk, police said.

After a day in the <NO1>sweltering <NO>sun watching some motorists stop for him and others zoom by obliviously, Adams stepped into the shade.

"A lot of people yield, and a lot of people don't," he said. "You've just got to watch the cars."

You can reach Staff Writer Julie Johnson at 521-5220 or julie.johnson@pressdemocrat.com. On Twitter @jjpressdem.