A 12-inch gas line is marked in yellow on a highway shoulder. How must the excavator work inside the tolerance zone?

1. Use a large excavator on the marks because the locator is presumed exact to the inch
2. Determine the precise location with noninvasive methods such as hand digging, potholing, or vacuum excavation before using mechanized equipment in the zone
3. Ignore the marks if the ticket is more than 20 days old and paint is still visible
4. Paint over the yellow marks with white so traffic will not see them