Haulers of Agriculture and Livestock Safety Act of 2020 or the HAULS Act of 2020 This bill modifies exemptions with respect to commercial motor vehicle safety regulations involving the transportation of agricultural commodities and farm supplies. The bill allows the federal hours-of-service rules exemption regarding maximum driving and on-duty time for drivers transporting agricultural commodities and farm supplies to apply year-round. Current law provides an exception from the federal hours-of-service rules for the transportation of agricultural commodities within a 150 air-mile radius of the normal work reporting location only during planting and harvest periods which are determined by each state. Additionally, the Department of Transportation must revise the definition of agricultural commodity to include specific commodities that are covered by the federal hours-of-service rules exception.