Drivers heading back to Southern California after spending Labor Day weekend in Las Vegas saw heavy traffic on southbound Interstate 15.

Traffic is barely moving as motorists travel to Southern California on the Interstate 15 from Las Vegas on Monday, Sept. 3, 2018. (Regional Transportation Commission)

Drivers heading back to Southern California after spending Labor Day weekend in Las Vegas should prepare for heavy traffic on southbound Interstate 15.

The Regional Transportation Commission reported at 6:15 p.m. that the backup stretched for 7 miles, down from 21 miles earlier in the day.

RTC traffic cameras show traffic is backed up to the Sloan exits. All three travel lanes are nearly bumper-to-bumper as you approach Primm.