MUKILTEO — Those who walk on the narrow sidewalk on the Highway 525 bridge near the waterfront know the drill.

When someone is coming in the opposite direction, start the body language to either step into the shoulder or wait for the other person to do it.

This should change when the sidewalk alongside northbound traffic is expanded by 4 feet — more than doubling the current width to 7½ feet wide.

Construction starts Sunday on the $2.2 million project awarded to contractor crews working for the state Department of Transportation. It will eliminate the shoulder and add compliant curb ramps and railing upgrades along the bridge, which was built over the railroad tracks in 1941 and rebuilt in 1967. Funding is through a Regional Mobility grant program.

“Projects like this are very important to communities,” said David Rasbach, a state Department of Transportation spokesperson. “It is going to create better access for people walking and using mobility devices to access the ferry terminal, the park and the waterfront businesses there.”

The work is scheduled to finish in December.

“With the weather, things could change,” Rasbach said.

The sidewalk is the main route to the waterfront for pedestrians to cross over the railroad tracks. The only other way is to use Mukilteo Lane and cross directly over the tracks to First Street.

During construction, the southbound sidewalk will remain open. Pedestrian traffic on the bridge should cross the highway using sidewalks at the First and Fifth street intersections.

Ferry terminal access will remain open during the work, but with some tweaks.

The terminal’s vehicle waiting line along northbound Highway 525 between First and Second streets will close from 10 p.m. and 8 a.m. Sunday through Tuesday morning and from 10 p.m. to 7 a.m. Wednesday through Friday morning.

A seven-day continuous closure of this stretch of the holding lane will begin at 8 a.m. Nov. 14. Police will direct traffic during peak ferry times.

“We are thrilled to see the much-anticipated sidewalk widening take place,” Mukilteo Mayor Joe Marine said. “Access to our waterfront is critical, and I am happy to see the state prioritize this project, which will enhance safety and walkability to and from the Mukilteo waterfront.”

Andrea Brown: 425-339-3443; abrown@heraldnet.com; Twitter: @reporterbrown.