Document Type

Journal Article

Publication Date


Subject Area

place - north america, mode - rail


Transportation industry, Transportation, Transport, Tank wagons, Tank cars, Risk analysis, Repeatability, North American Nonaccident Release Reduction Program, Nonaccident releases, Nonaccident release severity, Nonaccident release risk index, Hazardous substances, Hazardous materials, Dangerous goods, Class I railroads


Nonaccident releases (NAR) are the unintentional releases of a hazardous material while in transportation not resulting from a train accident. NARs are of significant concern to the shipping community due to their frequency, preventability, and cost. The North American Nonaccident Release Reduction Program was initiated in 1996 to help address the underlying causes of NARs and seek a substantial reduction in their frequency. Although the NAR Reduction Program showed significant gains initially, lately, NAR frequency, as measured by incidents per 1,000 tank-car originations, has held nearly steady. A new tool was therefore required to help the industry analyze the frequency, severity, and individual causes of NARs. In response, a working group consisting of all Class I railroads and several other interested parties developed the Nonaccident Release Risk Index (NARRI). The NARRI sought to assign a numerical score to represent the severity of any given NAR based on its preventability, the potential risk involved considering the type and quantity of hazardous material involved, and the consequences of the NAR. Significant effort was devoted to the project to ensure that the measures employed were based on objective criteria to the maximum extent possible. Significant effort was also devoted to verify the consistency of the measure across different NARs and the repeatability of the measure for an individual NAR across various scoring individuals.