Transportation Equity Act the 21st Century (TE-21) of 1998 requires explicit consideration of safety in the transportation planning process. While this government mandate is well intention, little is known about how to accomplish it. Despite 60 years of modern road building there is no consensus among transportation professionals as to how to quantify the degree of safety or un-safety of an existing transportation facility. It is even more difficult to anticipate safety of highways not yet build. To address both of these questions this paper will introduce the concept of Level of Service of Safety (LOSS) in the framework of Safety Performance Function (SPF). Safety Performance Function reflects complex relationship between traffic exposure and safety. The Level of Service of Safety (LOSS) makes it possible to accomplish the following: Qualitatively describe the degree of safety or un-safety of a roadway segment Effectively communicate the magnitude of the safety problem to other professionals or elected officials Bring perception of roadway safety in line with reality of safety performance reflecting a specific facility Provide a frame of reference for decision making on non-safety motivated projects (resurfacing or reconstruction for instance) Provide a frame of reference from a safety perspective for planning major corridor improvements.
Abstract