Caltrans says lanes will be closed at 10 a.m. for as long as 90 minutes every Tuesday and Thursday morning between Bailey and Nipton roads near Wheaton Springs, California. The closures are expected to go through the end of October.
Drivers looking to pass through either way are encouraged to wait in Baker, California, or Primm, Nevada, until the lanes are reopened.
The $91 million project is to widen about 12 miles of I-15 through Mountain Pass. The entire project should be completed in fall 2010.
The Associated Press contributed to this story.