Population density
(i) Population density. The population potentially exposed to an NRHM release shall be estimated from the density of the residents, employees, motorists, and other persons in the area, using United States census tract maps or other reasonable means for determining the population within a potential impact zone along a designated highway route. The impact zone is the potential range of effects in the event of a release. Special populations such as schools, hospitals, prisons, and senior citizen homes shall, among other things, be considered when determining the potential risk to the populations along a highway routing. Consideration shall be given to the amount of time during which an area will experience a heavy population density. (ii) Type of highway. The characteristics of each alternative NRHM highway routing designation shall be compared. Vehicle weight and size limits, underpass and bridge clearances, roadway geometrics, number of lanes, degree of access control, and median and shoulder structures are examples of characteristics which a State or Indian tribe shall consider. (iii) Types and quantities of NRHM. An examination shall be made of the type and quantity of NRHM normally transported along highway routes which are included in a proposed NRHM routing designation, and consideration shall be given to the relative impact zone and risks of each type and quantity. (iv) Emergency response capabilities. In consultation with the proper fire, law enforcement, and highway safety agencies, consideration shall be given to the emergency response capabilities which may be needed as a result of an NRHM routing designation. The analysis of the emergency response capabilities shall be based upon the proximity of the emergency response facilities and their capabilities to contain and suppress NRHM releases within the impact zones. (v) Results of consultation with affected persons. Consideration shall be given to the comments and concerns of all affected persons and entities provided during public hearings and consultations conducted in accordance with this section. (vi) Exposure and other risk factors. States and Indian tribes shall define the exposure and risk factors associated with any NRHM routing designations. The distance to sensitive areas shall be considered. Sensitive areas include, but are not limited to, homes and commercial buildings; special populations in hospitals, schools, handicapped facilities, prisons and stadiums; water sources such as streams and lakes; and natural areas such as parks, wetlands, and wildlife reserves. (vii) Terrain considerations. Topography along and adjacent to the proposed NRHM routing designation that may affect the potential severity of an accident, the dispersion of the NRHM upon release and the control and clean up of NRHM if released shall be considered. (viii) Continuity of routes. Adjacent jurisdictions shall be consulted to ensure routing continuity for NRHM across common borders. Deviations from the most direct route shall be minimized. (ix) Alternative routes. Consideration shall be given to the alternative routes to, or resulting from, any NRHM route designation. Alternative routes shall be examined, reviewed, or evaluated to the extent necessary to demonstrate that the most probable alternative routing resulting from a routing designation is safer than the current routing. (x) Effects on commerce. Any NRHM routing designation made in accordance with this subpart shall not create an unreasonable burden upon interstate or intrastate commerce. (xi) Delays in transportation. No NRHM routing designations may create unnecessary delays in the transportation of NRHM. (xii) Climatic conditions. Weather conditions unique to a highway route such as snow, wind, ice, fog, or other climatic conditions that could affect the safety of a route, the dispersion of the NRHM upon release, or increase the difficulty of controlling it and cleaning it up shall be given appropriate consideration. (xiii) Congestion and accident history. Traffic conditions unique to a highway routing such as: traffic congestion; accident experience with motor vehicles, traffic considerations that could affect the potential for an accident, exposure of the public to any release, ability to perform emergency response operations, or the temporary closing of a highway for cleaning up any release shall be given appropriate consideration.