Caltrans this week started a three-week project to dig out and replace stretches of pavement on Highway 29 in Calistoga and up over Mount St. Helena, and you can expect traffic delays.

The work will be 8 a.m. to 5 p.m. weekdays, except for Memorial Day, and will go from the intersection with Silverado Trail north to the Lake County line. The $5 million project is expected to finish on June 10.

One-way traffic controls will be in effect, so motorists can expect and should prepare for delays, especially on Mount St. Helena, where the roads twists and turns can make traffic backups dangerous.

The contractor is MCK Services Inc.