More than three years after two people died in crashes on Highway 116 in Cotati, safety changes that Caltrans once said would be done in 2011 are planned to start April 23.

"That should be a huge safety improvement for the region," said Cotati Mayor Mark Landman. "It is a longtime problem that we've all wanted to resolve."

The $606,000 project is to include 350-foot-long left-turn pockets in each direction of Highway 116 at Madrone Avenue, and a 5-foot shoulder on the intersection's south side. It will widen each lane from 35 feet to 46 feet.

In October 2009, Maria Juana Flores, 36, of Santa Rosa was killed when her car was rear-ended and pushed into the path of a big rig as she waited to make a left turn from the highway onto Madrone Avenue to pick up her children from school.

A Sonoma County jury in February said Caltrans was 25 percent responsible for the crash and should pay $3.1 million to Flores's family. The jury found the driver of the car that struck Flores's car responsible for the remaining share of the accident.

In a similar crash a month after Flores was killed, a car was struck as it turned left from the highway onto Madrone Avenue and into the path of a truck. The passenger in that car, Casa Grande High School student Anais Barajas Centeno, 17, died a week later of her injuries.

The driver of the car Centeno was in was later sentenced to 90 days of home confinement and probation for vehicular manslaughter and driving without a license.

The two deaths recharged efforts to convince the state to make changes to the road, a two-lane highway without turn or passing lanes. Madrone Avenue leads to an elementary school and drivers turning there often stop to wait for eastbound traffic to pass, as Flores was doing.

Caltrans within a year of the crashes installed new signs to clarify the area's speed limits and in 2010 said changes, including a new left turn lane making use of donated land, would start in 2011.

But the work was pushed back, in part because of the economic downturn and because the accidents were too few to qualify the stretch of highway as a priority project, Landman said.

Former Cotati Councilwoman Pat Gilardi was a leader in the efforts to push Caltrans to make the changes, which she had begun lobbying for years before the two crashes.

Gilardi, now Sonoma County Supervisor Susan Gorin's district director, said Tuesday of the improvements that she was "delighted that they're actually taking place."

But she said that such work is needed on a longer stretch of Highway 116 than at the Madrone Avenue intersection alone.

"That condition that exists at Madrone where people are queued up behind someone who is waiting to turn exists all along the highway," she said. "But I am grateful those improvements are scheduled."

Landman said Gilardi deserved major credit.

"She was responsible to a large degree for making this happen," he said.

The project is expected to last until July 30, Caltrans officials said, and will be done behind concrete barriers so as not to require road closures.

You can reach Staff Writer Jeremy Hay at 521-5212 or jeremy.hay@pressdemocrat.com.