Phase 1 of the Northeast Fourth Street extension project in downtown Bellevue is slated to start this month, and will expand Fourth from 116th Avenue Northeast to the Eastside Rail Corridor.

This is one of several projects by the city to address future growth in the downtown and Bel-Red areas in Bellevue, along with higher population draws once Sound Transit completes its East Link extension in 2023. KLB Construction will complete Phase 1 of the project under a $3.9 million contract bid award made using local, state and federal funding.

“We shouldn’t have any major traffic delays starting up this fall and in winter,” said Tresa Berg, city transportation department, adding more substantial lane detours and closures aren’t expected until summer.

Phase 1 construction will continue until the end of 2014, and occur 7 a.m. to 5 p.m. Monday-Friday and may include 9 a.m. to 6 p.m. on Saturdays.

The second phase of the Northeast Fourth extension project will connect to 120th Avenue Northeast, which also will be widened in several stages from Fourth to Northup Way. Phase 2 design is at 60 percent and construction is tentatively scheduled to begin in fall 2014.

“It’s a little bit of an ‘S’ curve that starts at 116th and heads to 120th,” said Berg.

The city is still working on right-of-way acquisitions with Best Buy and Home Depot as the extension will cut through their parking lots.