Until now, the eastbound lanes have carried traffic in both directions.
It will take a few days to get all the traffic barriers moved and all the ramps opened in that area, said Alan Hufstutler, and engineer on the project.
The US 83 South ramp is also scheduled to open sometime Monday evening.
Work on the $22.6 million project began in October 2006. Ramps on I-20 were relocated and frontage roads were switched to one-way from Spinks Road to FM 2404 and from US 84 to Ambler Ave.