Congress enacted the Omnibus Transportation Employee Testing Act of 1991 directing drug and alcohol testing for employees of transportation companies and agencies engaged in "safety sensitive functions." Some of the carriers are unionized and must comply with the requirements of either the National Labor Relations Act or the Railroad Labor Act. These laws prescribe bargaining requirements for employers. What happens when there is an intersection of the Omnibus Transportation Employee Testing Act of 1991, the National Labor Relations Act, or the Railroad Labor Act? This report examines the relationship between these laws, as well as the impact that intersections have had on existing collective bargaining agreements.