As the last two-lane part of the corridor between State Routes 99 and 18, South 277th Street in Auburn creates a choke point that causes congestion, slowing things down and creating safety issues.

To open it up and make it easier to get to the cities of Auburn, Kent, Federal Way and Covington, the City of Auburn is launching an 18-month-long construction project in July that adds 3,300 feet of intersection improvements and widens the roadway between Auburn Way North and L Street Northeast.

On Monday the Auburn City Council awarded the $5.5 million construction contract to Scarsella Bros. Inc. State and federal grants, private development and the City are paying for the work.

Of the four responsible bids submitted, Scarsell’s low bid came in about 9 percent below the City Engineer’s estimate.

The project was bid with a base bid and one additive bid, respectively, as follows:

• All work along South 277th Street from Auburn Way North to 750 feet east of L Street Northeast, including the addition of the two new eastbound through lanes; one new westbound through lane; street lighting improvements; storm drainage improvements; waterline improvements; streetscape improvements; Intelligent Transportation System (ITS) improvements; a variable message board sign; intersection capacity and safety improvements; and auxiliary turn lanes at Auburn Way North, D Street Northeast and the future I Street Northeast.

Finally, the project completes a separated, non-motorized trail connection between the Interurban and Green River Trail systems that connects to Kent’s trail across the Green River.

Based on the current engineer’s estimate of probable construction costs, City staff say, funding from secured grants and City funds will be enough to complete the base-bid work.

• Additive bid: All work on 83rd Avenue South from South 277th Street to 550 feet north, including the street lighting improvements, storm drainage improvements, sidewalks, a retaining wall, an auxiliary turn lane at 83rd Avenue South, and a grind and overlay of the pavement surface.

Motorists should expect lane closures, but the City intends to maintain at least one travel lane in each direction throughout the construction period. Generally, construction will occur between 7 a.m. and 6 p.m. Night work is not planned at this time but may be needed at some point.

When the work is done, the City expects to change the speed limit on the roadway from Auburn Way North to L Street Northeast to 35 miles per hour in both directions.