To solve the problem in a joint part of a paved road, particularly, a joint part of an expressway, in which when a vehicle passes through the joint part, a difference in frictional coefficient between a joint made of steel and the paved road may induce idling of a tire, resulting in a rear-end accident due to slippage, and in a joint at a curved part of the expressway, the vehicle may be laid in a state where a sufficient grounding force cannot be ensured due to extreme reduction in frictional coefficient at the time of passing through the joint and fall into a spinning state from slippage, causing a serious accident.

To solve the problem, a mixture of an adhesive and particles for ensuring the frictional coefficient is sprayed to a conventional iron-made joint.