Systematic Framework for Incorporating Safety in Network-Level Transportation Planning and Programming

Transportation agencies worldwide increasingly seek to abandon reactive approaches for safety enhancement in favor of approaches that incorporate safety in their transportation planning processes in a proactive, comprehensive, and systemwide context. To facilitate this task, this paper presents a framework which identifies candidate facilities in a transportation network for safety enhancement over a specified analysis period. Then for each candidate facility, the framework identifies safety enhancement projects on the basis of existing facility deficiencies and predominant accident patterns. Thus, a safety plan is developed to specify for each candidate facility, the year of the enhancement, the expected cost, and the resulting safety benefits. Also, where the safety budget is limited, the framework determines the subset of candidate facilities that should receive safety investment. At most transportation agencies, the typical transportation planning process is carried out only for engineering interventions. As such, the developed framework is engineering interventions only and thus excludes safety interventions related to road-user education, enforcement, and policy. With requisite data, the developed framework can be applied in safety planning and programming in the different modes of transportation-highway, airport, rail, and marine. Using an example in highway transportation, the paper applies the framework to develop a safety plan for a chosen network and thus demonstrates how safety could be included proactively in the network-level (systemwide) transportation planning process.