Agricultural Trucking Relief Act of 2018 This bill amends the Motor Carrier Safety Improvement Act of 1999 to revise the definition of "agricultural commodity" to include agricultural, aquacultural, horticultural, and floricultural commodities; fruits; vegetables; any non-human living animal and the products thereof; and other agriculture products that are sensitive to temperature or climate and at risk of perishing in transit. The transportation of agricultural commodities is exempt from requirements of such Act.