This invention is a method and apparatus for making a pressure-containing threaded tubular connection, suitable for remotely operated connection and separation, utilizing electrical heating to reduce the amount of makeup torque required to produce reliable preloading of the connection. Therefore, even if there are lane marks of different colors on the road, the lane marks of the respective colors can be recognized appropriately from the color image of the road acquired via the imaging means such as a camera. The respective glass ceramic materials constituting the unfired ceramic layer and the unfired overcoat layer are adjusted so that the ratio of a crystalline phase with a smaller coefficient of thermal expansion than the coefficient of thermal expansion of the fired ceramic layer is higher in the overcoat layer than in the ceramic layer.