The massive $11 million Dunlop Street construction project is underway in downtown Barrie.
Crews began work on Dunlop, east of Mulcaster, on Monday for water main and surface repairs.
The second phase of construction will see traffic disrupted on the busy section between Mulcaster and Owen Streets for two months starting in September.
The city will widen sidewalks by two-and-a-half-feet on either side, make the curbs wheelchair accessible, improve street lighting and create more winter parking.
Businesses along the construction route will remain open.
The final phase of the Dunlop Street corridor project, from Bayfield to Toronto Streets, will begin next year.
The entire project is expected to be completed in 2020.
