Chip sealing on Petrified Forest Road between Santa Rosa and Calistoga is expected to cause “extended traffic delays” today through Friday, the Sonoma County roads department warns.

In fact, Jen, a Road Warrior reader, wrote us that “the traffic is very backed up and wait times can exceed 15 minutes.” The backups are affecting traffic on Calistoga and Porter Creek roads as well.

Also facing “extended traffic delays” are drivers who use River Road between Highway 116 and Mirabel Road, where crews are doing striping work for the rest of the week, the roads department said in an announcement.