EDMONDS — Highway 99 could become more shaded, slower and safer along a stretch through Edmonds after a major project starting this month.

The city is removing the center left turn lane, sometimes derided as a “suicide” lane, from 210th to 244th Street SW. Most of that space will be replaced with a tree-lined curb median about 20 inches tall and mid-block left-turn pockets by next year. It’s a $10.2 million project, with most coming from the Legislature’s 2015 Connecting Washington transportation package.

Edmonds’ stretch of Highway 99 includes a combination of high speeds and high traffic volume. Most of the highway allows 45 mph and sees around 39,000 vehicles per day, according to Washington State Department of Transportation data.

Some crashes happened while drivers turned left into and from the center lane, said Lisa Reid, a planning engineer with consulting firm SCJ Alliance. Generally, left turns are dangerous, according to data analysis by the National Highway Traffic Safety Administration in 2010.

The road is lined with businesses, residences and sidewalks. Current speeds, traffic volume and distance between traffic signals with crosswalks make it a dangerous route for drivers and pedestrians.

“It’s going to add a lot of safety improvements,” Reid said last week during an online open house about the project.

Swapping the center turn lane with a median is part of the second stage in the city’s overhaul of its Highway 99 corridor. Eventually, two future stages will add lighting and wider sidewalks, improve crosswalks, bury utilities in some locations and bolster stormwater management.

One feature of this stage is a high-intensity activated crosswalk, called a HAWK signal, near 234th Street SW. It’ll be about halfway between a nearly mile-long gap without a crosswalk signal on the highway and “improve safety significantly,” Reid said.

People trying to roll or stroll across it can push a button. It will trigger a signal over the roadway that notifies drivers to slow via a yellow light or stop when red.

A similar device is getting installed on Highway 104 in Edmonds. They don’t stop vehicles the entire duration a person is in the crosswalk. Once a HAWK signal user is on the side of oncoming traffic, the light should flash red to let drivers know they’re almost clear.

The median strip will get 130 trees, an important tool to fight climate change as they provide shade and capture carbon dioxide.

Most of the work is scheduled 7 a.m. to 5 p.m. weekdays. Some evening construction will happen between 240th and 244th Street SW, where two lanes in each direction will be reduced to one lane each.

Significant traffic disruptions are not anticipated once the work is complete, Edmonds transportation engineer Bertrand Hauss said.

Ben Watanabe: 425-339-3037; bwatanabe@heraldnet.com; Twitter: @benwatanabe.