Nearly eight years to the day after a tragic accident claimed the lives of four Petaluma teenagers, the Sonoma County Board of Supervisors obtained the land necessary to reengineer the intersection to include a traffic light at Adobe Road and East Washington Street, just outside of the city's eastern boundary.

"The county has been working on this for a long time," said Tom O'Kane, deputy director of the county's Department of Transportation and Public Works. "As of the last (Board of Supervisor's) meeting, we've got everything we need to get going."

Construction should begin this summer and is expected to take about six months, after Pacific Gas and Electric moves two sets of power lines to create the space needed to expand the intersection. The plan calls for widening Adobe Road to add a right-hand turn lane, as well as new bike lanes. A four-way traffic signal will replace the flashing red light that currently warns drivers to stop.

Approximately $1 million has already been spent on design and permitting, and construction is expected to cost between $1.2 million and $1.5 million, O'Kane said. The process was slowed because the county relied on $900,000 in funds from the High Risk Rural Road program from the Federal Highway Administration.

"The problem you have is that there's a lot of additional permitting required when you have a federal grant," O'Kane said, explaining that the environmental reviews alone took three and a half years to complete.

The long-awaited stoplight was further delayed because additional land was needed to reengineer the intersection, land that initially was not for sale. The county considered utilizing eminent domain to procure the properties, but ultimately all four land owners agreed to give up small pieces of their land for the new intersection, ranging from 111.5 square feet from Buckeye Nursery, to 22,530 square feet from the nonprofit Science of the Soul Study Center.

"I don't even think we're taking an acre from anyone, it's just some little slivers near the roadway," O'Kane said.

Those slivers will make for a wider road and, ideally, one that's safer for motorists, bicyclists and pedestrians. While the intersection already has stop signs and a flashing red light to warn people to stop, county officials felt it wasn't enough.

"A stop sign is a great device, but it doesn't stop distractions," said Petaluma's representative, Supervisor David Rabbitt, who added that this stoplight has long been a goal for him to see finished. "This is to prevent future accidents, like the one that killed four Petaluma students several years ago."

On Dec. 13, 2005, Adrianna DeLaTorre, 18, was driving five of her friends in her Ford Taurus, when she pulled into the path of a delivery van while making a left turn onto Adobe Road. DeLaTorre and three of her passengers died, while the two others sustained serious injuries.

Shortly after the tragedy, county officials launched plans to bring a stoplight to the intersection in hopes of making it safer. At the time, there was only a stop sign on East Washington Street. The county was quick to install stop signs on Adobe Road along with flashing red lights to alert drivers, until the stoplight could be built. Since 2006, there have been 16 accidents at or near that intersection, resulting in seven injuries but no deaths, according to California Highway Patrol spokesman Jon Sloat.