Your commute on Ga. 400 is about to get worse. Then it’ll get better (maybe).

Work on the massive Ga. 400 express lanes project — one of the most expensive the state has ever pursued — officially kicked off Wednesday, ushering in years of construction with a promise that traffic will move faster — five years from now.

It’s a public-private partnership valued at $11 billion that will rebuild one of metro Atlanta’s most congested corridors over the next five years, adding 16 miles of express lanes and a dedicated busway. From the roof of a parking garage in Alpharetta overlooking the busy state route, state and national officials touted the work as a model for road projects everywhere.

“We are transforming the State Route 400 corridor not only for today, but for the next 50-plus years,” Russell McMurry, Georgia’s transportation commissioner, said at the event.

Completing the Ga. 400 express lanes, expected in early 2031, will get the Georgia Department of Transportation closer to its goal of an uninterrupted network of toll lanes throughout metro Atlanta. A similar public-private approach is how GDOT plans to build 40 miles of toll lanes on the top half of I-285, one of the next projects on its to-do list.

Unlike existing express lanes on I-85 and I-75, these toll lanes will be managed by a private company, SR 400 Peach Partners. In exchange for 50 years of toll revenue, the company, an international conglomerate of construction, engineering and financing partners, paid a $3.8 billion concession payment and will fund construction and maintenance along the route for the length of the contract.