EDMONDS — In the last five years, there were 8.61 accidents per million miles traveled along the 2½-mile Edmonds stretch of Highway 99, according to Washington State Department of Transportation data.

That’s more than 3½ times the statewide average.

One-quarter of those accidents occurred when drivers were leaving or entering the highway’s two-way left turn lane. A new plan from the city of Edmonds would separate both directions of traffic with a median, with the hope that it will cut down on collisions.

On Tuesday, the city council unanimously approved the project, spanning from 244th Street to 210th Street.

“I am so excited to see this,” council member Susan Paine said. “This will be a nice improvement for the residents up there.”

The new median is step one of seven in the the Highway 99 transportation plan passed by the city council in 2017. In total, the renovation is set to cost $129 million.

Phase one will cost about $6.5 million. The bill will be covered by dollars from Connecting Washington, a $16 billion transportation investment program fueled primarily by a gas tax increase.

In addition to the median, the city is looking to add a traffic signal between 228th and 238th streets.

After that, the city wants to widen sidewalks by adding green-space buffers. However, that would require more money from the state.

Highway 99’s upgrades come as the city looks to its transit corridor for density housing and economic growth — a theme echoed by nearly every political leader in Edmonds.

“It will be transformative,” Paine said. “I think there’s great connectivity from 99 over to the Mountlake Terrace transit center hub.”

The design process will start this year, said Phil Williams, director of Public Works in Edmonds. Construction could break ground in 2021.

Before that happens, the city needs to have “full-fledged discussions with business owners to let them know what’s going on,” Paine said.

“We have to do this right,” she said.

The project also comes on the heels of a similar renovation just south of the state route in Edmonds.

In 2017, the city of Shoreline completed its Aurora Avenue corridor project. Shoreline’s upgrades included a landscaped median and two HAWK signals, traffic devices that stop cars so pedestrians can use a crosswalk.

When the medians are installed, some drivers may be confused about where they can turn left on Highway 99. Paine is confident drivers will figure it out quickly, she said.

“If they can do it in Shoreline, I’m sure we can do it in Edmonds,” she said.

Joey Thompson: 425-339-3449; jthompson@heraldnet.com. Twitter: @byjoeythompson.