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26 Guidebook for Conducting Local Hazardous Materials Commodity Flow Studies Classifying Transportation Modes and Routes Roadways include, but are not limited to, Interstate highways, U.S. highways, state highways, urban arterials, and secondary roads such as county roads, farm roads, and forest roads. Railways include Class I railroads that operate over large portions of North America, regional Class II railroads, shortline Class III railroads, and port, termi- nal, and industrial railroads. Pipelines include petroleum crude pipelines, petroleum product pipelines, nat- ural gas transmission lines, natural gas collection and distribution lines, carbon dioxide lines, and other hazardous liquids lines. Navigable waterways are those that can accommodate either shallow draft vessels such as barges and tow/push-boats, or deep draft vessels. Shallow draft channels, generally 15 feet deep or less, serve smaller ports as well as industrial facilities. Deep draft waterways serve larger ports as well as industrial facilities. Airline terminals include intercontinental, international, national, and regional airports. Many airports have designated cargo facilities served by airlines that focus on cargo transportation. However, passenger airlines also offer cargo services. hazmat transport, high-risk locations such as hairpin turns, steep curves, or blind intersections and entrances can increase the likelihood of incident occurrence. Including this experiential knowledge does not require a formal assessment and documentation--that may be covered as part of the new data collection (discussed in Section 4.2.3). However, discussing this informa- tion with local emergency managers and responders as part of the baseline knowledge assess- ment can help identify whether and where additional information is needed. 3.2 Review and Evaluate Baseline Information The project team reviews and evaluates the baseline information to identify a preliminary in- ventory of what is immediately and currently known about hazmat flow into, out of, within, and through the study area. The review will help the project team scope the HMCFS existing data collection, new data collection, and analysis. Things to Look for in the Baseline Information Review The preliminary inventory of hazmat flows allows planners to focus on routes as follows where: There is reason to believe risks are high (e.g., high frequency or volume, high traffic counts, or recent accidents, especially those involving hazmat); Knowledge is limited or undocumented (i.e., there is little or no empirical evidence); Potential exposures are extreme (i.e., large populations, special needs popula- tions, or large congregations of people are frequently or routinely present); or Some combination of these is present.

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Collect and Review Baseline Information and Scope Project 27 Ideally, previous documentation (such as a prior HMCFS) would be recent and specifically focused on hazmat transport over the corridors of concern. However, even an HMCFS that was not conducted recently can be useful for developing a baseline of existing knowledge. Routes or route segments can be classified by mode of transport, frequency and volume of hazardous materials, and extent of knowledge currently available. Hazmat transport is possible along any route, but the amount and frequency varies with mode and class. Characteristics of Hazmat Transport by Types of Roadways Large quantities of hazardous materials are frequently transported on the nation's highways. The primary function of many highways is transporting through traffic. This often makes Interstates, freeways, highways, and other limited-access roadways the highest priority for study. Routes may be identi- fied as permitting or restricting hazmat transport. Because primary or arterial roadways provide through movement with some access to adjacent land, they also typically receive high priority for study. To the extent that flows on limited access roadways are already understood, they may receive lower consideration. Secondary or collector roadways provide access to the adjacent land and links to primary roadway and highway networks. Understanding these connections may be relevant to locations serving major industrial or transportation hubs in the area. Local or tertiary streets are primarily for land access and likely represent the fixed facilities they directly serve. Railways transport very high quantities of commodities per unit, and although in many areas the transport of hazardous materials by railway may be less frequent than by roadways, it still may be significant. Hazardous materials are frequently transported throughout the Class I rail system. Regional railroads (Class II), because of the exchange of traffic with the Class I system, are considered very likely to handle hazardous materials with considerable volume and fre- quency. Many shortline railroads carry only a limited variety of commodities. For some short- lines, this will generally exclude hazardous materials, but hazardous material may make up almost all of the carload shipments for others. This generally holds for switching and terminal or port railroads as well, which are the smallest of the rail system types. Railways designated only for passenger railroads can be eliminated from consideration, except where they may intersect other hazmat corridors (e.g., a highwayrail grade crossing in an industrial area). Generally, pipelines are constructed to carry liquid commodities with consistently high vol- ume and frequency. Petroleum crude pipelines, petroleum product pipelines, natural gas trans- mission lines, and pipelines that carry other hazardous liquids (e.g., ammonia) often are of high interest for an HMCFS, given the nature of their hazards and the volume of hazardous material each carries. Waterways are especially well suited to transporting large quantities of commodi- ties. Airport terminals may be used for transport of hazmat cargo, although the volume of haz- mat air cargo transport is much lower than that of other modes, and airports are accessed by connecting roadways. Airport terminals may also receive aviation fuels by different modes. Major shipping routes into or out of fixed facilities that produce, store or use hazardous ma- terials within the study area are highly likely to exhibit significant volumes or frequency of haz- mat transport. Routes and facility locations may be classified in terms of the potential exposure