Construction on the initial part of a $7 billion project to overhaul I-45 from Beltway 8 in North Houston to Spur 527 at Hwy. 59 near downtown is expected to begin by 2020, according to the Texas Department of Transportation.

The North Houston Highway Improvement Project spans 24 miles and is needed to address inadequate highway capacity for existing and future traffic demands along the corridor, according to TxDOT. Between 2015 and 2040, average daily traffic volumes in the corridor are projected to increase by as much as 30 percent.

A large portion of the project involves rerouting the highway system in downtown Houston by replacing the existing elevated section of I-45 on the west and south sides of downtown—referred to by TxDOT as the Pierce Elevated—with connectors allowing access to and from various city streets. I-45 would be rerouted to run parallel to I-10 on the north side of the city and parallel to I-69 on the city’s east side, according to TxDOT.

Two express lanes in each direction would also be constructed on I-10 from west of I-45 to east of I-69, allowing through traffic on I-10 to bypass downtown Houston, according to TxDOT.

Additionally, drivers who commute from The Woodlands using I-45 will see the addition of two managed express lanes in both directions in the middle of the freeway. The lanes would include both high-occupancy vehicle and toll operations.

The project also involves rebuilding the Loop 610 and I-45 interchange in North Houston but does not involve changes to the Beltway 8 interchange.

“[The Loop 610 interchange] will be completely rebuilt where we get rid of the left-hand merges and entrances and go to a more conventional freeway-to-freeway interchange,” said Pat Henry, director of project development for TxDOT’s Houston District.

Funding for the initial phases of construction has been identified, which involves the section near downtown at Hwy. 59 from Spur 527 to Hwy. 288.

As part of a March update of the Unified Transportation Plan, TxDOT presented roughly $8 billion in projects to begin executing over the next four years, which includes funding for the I-45 overhaul.

TxDOT will finalize the environmental analysis from 2017-18 and receive a project decision by 2018. Right of way acquisition could begin between 2018-2020. Construction would be completed in phases as additional funding is identified, progressing from south to north.

TxDOT will gather public comments by mail or electronically via email for the project through June 27.